Infectious Diseases

Samples from patients in the United States and Kenya show an increasing emergence of previously undetected vancomycin-resistant strains of Clostridioides difficile, sparking concern as recurrences in the treatment of C. difficile infection (CDI) continue to rise.

“Our results may help explain a decreasing effectiveness of antibiotic-based therapy in C. difficile infection, since a significant proportion of patients harboring strains with reduced susceptibility to vancomycin may not respond to treatment,” reported the authors in research published recently in Clinical Infectious Diseases.

The spread of the resistant strains “has serious public health implications, underscoring an urgent need for a comprehensive analysis of the circulating strains to help inform clinical decisions,” they added.

Commenting on the findings, Cornelius J. Clancy, MD, professor of medicine at the University of Pittsburgh, and chief of infectious diseases at the Veterans Affairs Pittsburgh Healthcare System, echoed the concern.

“The casual belief has been that [C. difficile] strains at most centers can be assumed to be vancomycin susceptible,” he told this news organization. “This study shows that this assumption can no longer be taken as a given.”

Dr. Clancy, who was not involved with this research, noted that “based on this study, there might be need for the Infectious Diseases Society of America and other organizations to offer guidance on generating good, quality surveillance data for C. difficile resistance.”

With C. difficile showing the ability to resist multiple antibiotics, drugs in the armamentarium to treat the infection have declined in recent years, and recurrences with the infection are reported in up to 25% of cases.

Oral vancomycin is recommended as the antibiotic of choice by the IDSA and the Society for Healthcare Epidemiology of America for severe as well as nonsevere cases of CDI, and although there are reports of nine vancomycin-resistant gene clusters, most involve Enterococcus.

To take a closer look at the prevalence of vancomycin-resistant C. difficile strains, first author Charles Darkoh, PhD, with the Center for Infectious Diseases at the University of Texas Health Science Center, Houston, and colleagues analyzed stool samples from patients with CDI, including 438 patients in Houston, taken between 2012 and 2017, and 98 in Nairobi, Kenya, taken in 2017.

They found that, among samples from patients in Houston, over the time period, 26% showed vancomycin nonsusceptible C. difficile isolates and 29% had isolates that were metronidazole resistant.

And among samples from the Nairobi patients, 67% harbored vancomycin-resistant isolates and 85% had isolates resistant to metronidazole.

Of note, the proportion of samples containing vancomycin-resistant C. difficile in the Houston patients showed a marked increase over time, from «complete absence» in 2012 to approximately 35% in 2017, the authors reported.

“These nonsusceptibility rates significantly exceeded prior reports from other studies conducted in the United States and Europe from 2011 to 2014, suggesting a lower percentage of resistance to both metronidazole and vancomycin,” the authors wrote.

Further experiments on mouse models infected with one of the vancomycin-resistant isolates showed that treatment with vancomycin failed to eradicate the infection, and 5-day survival was significantly lower after vancomycin treatment in those mice (25%) versus those infected with strains known to be vancomycin sensitive (50%).
 

Unrecognized genetic strains

Whole-genome sequencing of 10 of the resistant isolates showed no matches with gene clusters that have been previously recognized as being vancomycin resistant, suggesting the emergence of new clusters.

“Together, these results suggest unknown genetic elements associated with vancomycin nonsusceptibility in isolates circulating in the patient population,” the authors wrote.

Dr. Darkoh told this news organization that the research team is currently working to further investigate the patterns and mechanisms.

“We are currently working on a follow-up study for the next 5 years to find out how widespread this is,” he said. “We want to make sure it’s not necessarily just occurring in the settings we studied, and we also need to establish the mechanism of resistance.”

Further commenting on the results, Dr. Clancy noted that “the extent of resistance caught many in the field a bit off guard, as they are higher than previously reported.”

“The data are also concerning because most centers do not routinely test C. difficile for drug susceptibility.”

Dr. Clancy noted that “another immediately pressing need is to understand mechanisms of resistance. It was quite striking that vancomycin-resistant strains in this study did not carry vanA genes, pointing to previously unrecognized mechanisms of resistance.”

“As is often the case, antibiotic overuse was likely a factor in the resistances, with overtesting often leading to overtreatment of C. difficile,” Dr. Clancy said. “The situation may have been compounded by failure to appreciate how entrenched C. difficile resistance may be at certain hospitals, since widespread susceptibility testing is generally not routinely performed.”

As alternative treatments, Dr. Clancy pointed to the recent IDSA update, which included a stronger endorsement of fidaxomicin.

“Of course, there is also the need to assure that data on resistance to agents like fidaxomicin are generated going forward,” he noted.

The study was supported by was supported by National Institutes of Health, the National Institute of Allergy and Infectious Diseases, the Texas Medical Center Digestive Diseases Center, and the University of Texas Health Science Center. Dr. Darkoh has disclosed no relevant financial relationships. One coauthor received grant support from Merck, Entasis Pharmaceuticals, and MeMed Diagnostics. Dr. Clancy disclosed advisory board, consulting and/or research relationships with Merck, Qpex Biopharma, Shionogi, Astellas, Cidara, Scynexis, and Needham & Associates.

Help your patients understand their C. difficile diagnosis by sharing patient education from the AGA GI Patient Center: www.gastro.org/Cdiff. 

A version of this article first appeared on Medscape.com.

Samples from patients in the United States and Kenya show an increasing emergence of previously undetected vancomycin-resistant strains of Clostridioides difficile, sparking concern as recurrences in the treatment of C. difficile infection (CDI) continue to rise.

“Our results may help explain a decreasing effectiveness of antibiotic-based therapy in C. difficile infection, since a significant proportion of patients harboring strains with reduced susceptibility to vancomycin may not respond to treatment,” reported the authors in research published recently in Clinical Infectious Diseases.

The spread of the resistant strains “has serious public health implications, underscoring an urgent need for a comprehensive analysis of the circulating strains to help inform clinical decisions,” they added.

Commenting on the findings, Cornelius J. Clancy, MD, professor of medicine at the University of Pittsburgh, and chief of infectious diseases at the Veterans Affairs Pittsburgh Healthcare System, echoed the concern.

“The casual belief has been that [C. difficile] strains at most centers can be assumed to be vancomycin susceptible,” he told this news organization. “This study shows that this assumption can no longer be taken as a given.”

Dr. Clancy, who was not involved with this research, noted that “based on this study, there might be need for the Infectious Diseases Society of America and other organizations to offer guidance on generating good, quality surveillance data for C. difficile resistance.”

With C. difficile showing the ability to resist multiple antibiotics, drugs in the armamentarium to treat the infection have declined in recent years, and recurrences with the infection are reported in up to 25% of cases.

Oral vancomycin is recommended as the antibiotic of choice by the IDSA and the Society for Healthcare Epidemiology of America for severe as well as nonsevere cases of CDI, and although there are reports of nine vancomycin-resistant gene clusters, most involve Enterococcus.

To take a closer look at the prevalence of vancomycin-resistant C. difficile strains, first author Charles Darkoh, PhD, with the Center for Infectious Diseases at the University of Texas Health Science Center, Houston, and colleagues analyzed stool samples from patients with CDI, including 438 patients in Houston, taken between 2012 and 2017, and 98 in Nairobi, Kenya, taken in 2017.

They found that, among samples from patients in Houston, over the time period, 26% showed vancomycin nonsusceptible C. difficile isolates and 29% had isolates that were metronidazole resistant.

And among samples from the Nairobi patients, 67% harbored vancomycin-resistant isolates and 85% had isolates resistant to metronidazole.

Of note, the proportion of samples containing vancomycin-resistant C. difficile in the Houston patients showed a marked increase over time, from «complete absence» in 2012 to approximately 35% in 2017, the authors reported.

“These nonsusceptibility rates significantly exceeded prior reports from other studies conducted in the United States and Europe from 2011 to 2014, suggesting a lower percentage of resistance to both metronidazole and vancomycin,” the authors wrote.

Further experiments on mouse models infected with one of the vancomycin-resistant isolates showed that treatment with vancomycin failed to eradicate the infection, and 5-day survival was significantly lower after vancomycin treatment in those mice (25%) versus those infected with strains known to be vancomycin sensitive (50%).
 

Unrecognized genetic strains

Whole-genome sequencing of 10 of the resistant isolates showed no matches with gene clusters that have been previously recognized as being vancomycin resistant, suggesting the emergence of new clusters.

“Together, these results suggest unknown genetic elements associated with vancomycin nonsusceptibility in isolates circulating in the patient population,” the authors wrote.

Dr. Darkoh told this news organization that the research team is currently working to further investigate the patterns and mechanisms.

“We are currently working on a follow-up study for the next 5 years to find out how widespread this is,” he said. “We want to make sure it’s not necessarily just occurring in the settings we studied, and we also need to establish the mechanism of resistance.”

Further commenting on the results, Dr. Clancy noted that “the extent of resistance caught many in the field a bit off guard, as they are higher than previously reported.”

“The data are also concerning because most centers do not routinely test C. difficile for drug susceptibility.”

Dr. Clancy noted that “another immediately pressing need is to understand mechanisms of resistance. It was quite striking that vancomycin-resistant strains in this study did not carry vanA genes, pointing to previously unrecognized mechanisms of resistance.”

“As is often the case, antibiotic overuse was likely a factor in the resistances, with overtesting often leading to overtreatment of C. difficile,” Dr. Clancy said. “The situation may have been compounded by failure to appreciate how entrenched C. difficile resistance may be at certain hospitals, since widespread susceptibility testing is generally not routinely performed.”

As alternative treatments, Dr. Clancy pointed to the recent IDSA update, which included a stronger endorsement of fidaxomicin.

“Of course, there is also the need to assure that data on resistance to agents like fidaxomicin are generated going forward,” he noted.

The study was supported by was supported by National Institutes of Health, the National Institute of Allergy and Infectious Diseases, the Texas Medical Center Digestive Diseases Center, and the University of Texas Health Science Center. Dr. Darkoh has disclosed no relevant financial relationships. One coauthor received grant support from Merck, Entasis Pharmaceuticals, and MeMed Diagnostics. Dr. Clancy disclosed advisory board, consulting and/or research relationships with Merck, Qpex Biopharma, Shionogi, Astellas, Cidara, Scynexis, and Needham & Associates.

Help your patients understand their C. difficile diagnosis by sharing patient education from the AGA GI Patient Center: www.gastro.org/Cdiff. 

A version of this article first appeared on Medscape.com.

Samples from patients in the United States and Kenya show an increasing emergence of previously undetected vancomycin-resistant strains of Clostridioides difficile, sparking concern as recurrences in the treatment of C. difficile infection (CDI) continue to rise.

“Our results may help explain a decreasing effectiveness of antibiotic-based therapy in C. difficile infection, since a significant proportion of patients harboring strains with reduced susceptibility to vancomycin may not respond to treatment,” reported the authors in research published recently in Clinical Infectious Diseases.

The spread of the resistant strains “has serious public health implications, underscoring an urgent need for a comprehensive analysis of the circulating strains to help inform clinical decisions,” they added.

Commenting on the findings, Cornelius J. Clancy, MD, professor of medicine at the University of Pittsburgh, and chief of infectious diseases at the Veterans Affairs Pittsburgh Healthcare System, echoed the concern.

“The casual belief has been that [C. difficile] strains at most centers can be assumed to be vancomycin susceptible,” he told this news organization. “This study shows that this assumption can no longer be taken as a given.”

Dr. Clancy, who was not involved with this research, noted that “based on this study, there might be need for the Infectious Diseases Society of America and other organizations to offer guidance on generating good, quality surveillance data for C. difficile resistance.”

With C. difficile showing the ability to resist multiple antibiotics, drugs in the armamentarium to treat the infection have declined in recent years, and recurrences with the infection are reported in up to 25% of cases.

Oral vancomycin is recommended as the antibiotic of choice by the IDSA and the Society for Healthcare Epidemiology of America for severe as well as nonsevere cases of CDI, and although there are reports of nine vancomycin-resistant gene clusters, most involve Enterococcus.

To take a closer look at the prevalence of vancomycin-resistant C. difficile strains, first author Charles Darkoh, PhD, with the Center for Infectious Diseases at the University of Texas Health Science Center, Houston, and colleagues analyzed stool samples from patients with CDI, including 438 patients in Houston, taken between 2012 and 2017, and 98 in Nairobi, Kenya, taken in 2017.

They found that, among samples from patients in Houston, over the time period, 26% showed vancomycin nonsusceptible C. difficile isolates and 29% had isolates that were metronidazole resistant.

And among samples from the Nairobi patients, 67% harbored vancomycin-resistant isolates and 85% had isolates resistant to metronidazole.

Of note, the proportion of samples containing vancomycin-resistant C. difficile in the Houston patients showed a marked increase over time, from «complete absence» in 2012 to approximately 35% in 2017, the authors reported.

“These nonsusceptibility rates significantly exceeded prior reports from other studies conducted in the United States and Europe from 2011 to 2014, suggesting a lower percentage of resistance to both metronidazole and vancomycin,” the authors wrote.

Further experiments on mouse models infected with one of the vancomycin-resistant isolates showed that treatment with vancomycin failed to eradicate the infection, and 5-day survival was significantly lower after vancomycin treatment in those mice (25%) versus those infected with strains known to be vancomycin sensitive (50%).
 

Unrecognized genetic strains

Whole-genome sequencing of 10 of the resistant isolates showed no matches with gene clusters that have been previously recognized as being vancomycin resistant, suggesting the emergence of new clusters.

“Together, these results suggest unknown genetic elements associated with vancomycin nonsusceptibility in isolates circulating in the patient population,” the authors wrote.

Dr. Darkoh told this news organization that the research team is currently working to further investigate the patterns and mechanisms.

“We are currently working on a follow-up study for the next 5 years to find out how widespread this is,” he said. “We want to make sure it’s not necessarily just occurring in the settings we studied, and we also need to establish the mechanism of resistance.”

Further commenting on the results, Dr. Clancy noted that “the extent of resistance caught many in the field a bit off guard, as they are higher than previously reported.”

“The data are also concerning because most centers do not routinely test C. difficile for drug susceptibility.”

Dr. Clancy noted that “another immediately pressing need is to understand mechanisms of resistance. It was quite striking that vancomycin-resistant strains in this study did not carry vanA genes, pointing to previously unrecognized mechanisms of resistance.”

“As is often the case, antibiotic overuse was likely a factor in the resistances, with overtesting often leading to overtreatment of C. difficile,” Dr. Clancy said. “The situation may have been compounded by failure to appreciate how entrenched C. difficile resistance may be at certain hospitals, since widespread susceptibility testing is generally not routinely performed.”

As alternative treatments, Dr. Clancy pointed to the recent IDSA update, which included a stronger endorsement of fidaxomicin.

“Of course, there is also the need to assure that data on resistance to agents like fidaxomicin are generated going forward,” he noted.

The study was supported by was supported by National Institutes of Health, the National Institute of Allergy and Infectious Diseases, the Texas Medical Center Digestive Diseases Center, and the University of Texas Health Science Center. Dr. Darkoh has disclosed no relevant financial relationships. One coauthor received grant support from Merck, Entasis Pharmaceuticals, and MeMed Diagnostics. Dr. Clancy disclosed advisory board, consulting and/or research relationships with Merck, Qpex Biopharma, Shionogi, Astellas, Cidara, Scynexis, and Needham & Associates.

Help your patients understand their C. difficile diagnosis by sharing patient education from the AGA GI Patient Center: www.gastro.org/Cdiff. 

A version of this article first appeared on Medscape.com.

The indication of an Omicron decline has become a trend: New cases of COVID-19 in children were down for a second consecutive week in the United States, according to the American Academy of Pediatrics and the Children’s Hospital Association.

The total for the week of Jan. 28 to Feb. 3 was still “extremely high, over double the peak level of the Delta surge in 2021,” the AAP noted, but the nearly 632,000 cases reported were down by 22% from the previous week and by 45% from what appears to be the peak of the Omicron surge during the week of Jan. 14-20, the AAP/CHA data show.

To put the effect of the Delta and Omicron variants into some sort of perspective, the total number of COVID-19 cases among children passed 5 million at the beginning of September 2021, about a year and a half into the pandemic. In the last 5 months, the cumulative count has more than doubled and now stands at 12 million, the AAP and CHA said in their weekly COVID report.

Hospital admissions and emergency department visits followed the same downward trend over the last week. The rate of new hospitalizations fell to 0.81 per 100,000 children aged 0-17 years as of Feb. 2 (down from a peak of 1.25 per 100,000 on Jan. 15), and ED visits with diagnosed COVID-19 dropped to 1.8% (peak was 14.1%), 1.9% (peak was 14.3%), and 3.4% (peak was 14%) of all visits for children aged 16-17, 12-15, and 0-11 years, respectively, the Centers for Disease Control and Prevention reported.

The vaccination response

The surge of infections brought about by the Omicron variant, however, did not translate into increased vaccination, at least for the youngest eligible children. Vaccine initiation rose slightly among children aged 5-11 in early and mid-January but, by early February, new vaccinations had declined to their lowest point since approval in early November of 2021, the AAP said in its weekly COVID vaccination report.

As a result, the 5- to 11-year-olds are well behind the pace set by those aged 12-15 for the first 3 months of their vaccination experience. Through the first 13 weeks after the COVID vaccine was approved for children aged 12-15 in early May, 44.5% had received at least one dose and 32.3% were fully vaccinated. Among children aged 5-11, the corresponding figures through 13 weeks were 31% and 22.5%, according to CDC data.

The vaccination reaction to Omicron was somewhat more robust for children aged 12-17, compared with the younger group, but initiations dropped at the same time that new cases began to decline. In terms of total volume, the response among 12- to 17-year-olds was much smaller than that seen in July and August of 2021 as the Delta surge was hitting the United States, the AAP vaccination report shows.

All those vaccinations add up to this: Over 16.8 million children aged 12-17 and almost 9 million aged 5-11 had received at least one dose of vaccine as of Feb. 7, which works out to 66.6% of the older group and 31.2% of the younger cohort. Almost 14.3 million (56.4%) of those aged 12-17 are fully vaccinated, as are 6.6 million (22.9%) of the 5- to 11-year-olds, the CDC said on its COVID Data Tracker.

The indication of an Omicron decline has become a trend: New cases of COVID-19 in children were down for a second consecutive week in the United States, according to the American Academy of Pediatrics and the Children’s Hospital Association.

The total for the week of Jan. 28 to Feb. 3 was still “extremely high, over double the peak level of the Delta surge in 2021,” the AAP noted, but the nearly 632,000 cases reported were down by 22% from the previous week and by 45% from what appears to be the peak of the Omicron surge during the week of Jan. 14-20, the AAP/CHA data show.

To put the effect of the Delta and Omicron variants into some sort of perspective, the total number of COVID-19 cases among children passed 5 million at the beginning of September 2021, about a year and a half into the pandemic. In the last 5 months, the cumulative count has more than doubled and now stands at 12 million, the AAP and CHA said in their weekly COVID report.

Hospital admissions and emergency department visits followed the same downward trend over the last week. The rate of new hospitalizations fell to 0.81 per 100,000 children aged 0-17 years as of Feb. 2 (down from a peak of 1.25 per 100,000 on Jan. 15), and ED visits with diagnosed COVID-19 dropped to 1.8% (peak was 14.1%), 1.9% (peak was 14.3%), and 3.4% (peak was 14%) of all visits for children aged 16-17, 12-15, and 0-11 years, respectively, the Centers for Disease Control and Prevention reported.

The vaccination response

The surge of infections brought about by the Omicron variant, however, did not translate into increased vaccination, at least for the youngest eligible children. Vaccine initiation rose slightly among children aged 5-11 in early and mid-January but, by early February, new vaccinations had declined to their lowest point since approval in early November of 2021, the AAP said in its weekly COVID vaccination report.

As a result, the 5- to 11-year-olds are well behind the pace set by those aged 12-15 for the first 3 months of their vaccination experience. Through the first 13 weeks after the COVID vaccine was approved for children aged 12-15 in early May, 44.5% had received at least one dose and 32.3% were fully vaccinated. Among children aged 5-11, the corresponding figures through 13 weeks were 31% and 22.5%, according to CDC data.

The vaccination reaction to Omicron was somewhat more robust for children aged 12-17, compared with the younger group, but initiations dropped at the same time that new cases began to decline. In terms of total volume, the response among 12- to 17-year-olds was much smaller than that seen in July and August of 2021 as the Delta surge was hitting the United States, the AAP vaccination report shows.

All those vaccinations add up to this: Over 16.8 million children aged 12-17 and almost 9 million aged 5-11 had received at least one dose of vaccine as of Feb. 7, which works out to 66.6% of the older group and 31.2% of the younger cohort. Almost 14.3 million (56.4%) of those aged 12-17 are fully vaccinated, as are 6.6 million (22.9%) of the 5- to 11-year-olds, the CDC said on its COVID Data Tracker.

The indication of an Omicron decline has become a trend: New cases of COVID-19 in children were down for a second consecutive week in the United States, according to the American Academy of Pediatrics and the Children’s Hospital Association.

The total for the week of Jan. 28 to Feb. 3 was still “extremely high, over double the peak level of the Delta surge in 2021,” the AAP noted, but the nearly 632,000 cases reported were down by 22% from the previous week and by 45% from what appears to be the peak of the Omicron surge during the week of Jan. 14-20, the AAP/CHA data show.

To put the effect of the Delta and Omicron variants into some sort of perspective, the total number of COVID-19 cases among children passed 5 million at the beginning of September 2021, about a year and a half into the pandemic. In the last 5 months, the cumulative count has more than doubled and now stands at 12 million, the AAP and CHA said in their weekly COVID report.

Hospital admissions and emergency department visits followed the same downward trend over the last week. The rate of new hospitalizations fell to 0.81 per 100,000 children aged 0-17 years as of Feb. 2 (down from a peak of 1.25 per 100,000 on Jan. 15), and ED visits with diagnosed COVID-19 dropped to 1.8% (peak was 14.1%), 1.9% (peak was 14.3%), and 3.4% (peak was 14%) of all visits for children aged 16-17, 12-15, and 0-11 years, respectively, the Centers for Disease Control and Prevention reported.

The vaccination response

The surge of infections brought about by the Omicron variant, however, did not translate into increased vaccination, at least for the youngest eligible children. Vaccine initiation rose slightly among children aged 5-11 in early and mid-January but, by early February, new vaccinations had declined to their lowest point since approval in early November of 2021, the AAP said in its weekly COVID vaccination report.

As a result, the 5- to 11-year-olds are well behind the pace set by those aged 12-15 for the first 3 months of their vaccination experience. Through the first 13 weeks after the COVID vaccine was approved for children aged 12-15 in early May, 44.5% had received at least one dose and 32.3% were fully vaccinated. Among children aged 5-11, the corresponding figures through 13 weeks were 31% and 22.5%, according to CDC data.

The vaccination reaction to Omicron was somewhat more robust for children aged 12-17, compared with the younger group, but initiations dropped at the same time that new cases began to decline. In terms of total volume, the response among 12- to 17-year-olds was much smaller than that seen in July and August of 2021 as the Delta surge was hitting the United States, the AAP vaccination report shows.

All those vaccinations add up to this: Over 16.8 million children aged 12-17 and almost 9 million aged 5-11 had received at least one dose of vaccine as of Feb. 7, which works out to 66.6% of the older group and 31.2% of the younger cohort. Almost 14.3 million (56.4%) of those aged 12-17 are fully vaccinated, as are 6.6 million (22.9%) of the 5- to 11-year-olds, the CDC said on its COVID Data Tracker.

Samples from patients in the United States and Kenya show an increasing emergence of previously undetected vancomycin-resistant strains of Clostridioides difficile, sparking concern as recurrences in the treatment of C. difficile infection (CDI) continue to rise.

“Our results may help explain a decreasing effectiveness of antibiotic-based therapy in C. difficile infection, since a significant proportion of patients harboring strains with reduced susceptibility to vancomycin may not respond to treatment,” reported the authors in research published recently in Clinical Infectious Diseases.

The spread of the resistant strains “has serious public health implications, underscoring an urgent need for a comprehensive analysis of the circulating strains to help inform clinical decisions,” they added.

Commenting on the findings, Cornelius J. Clancy, MD, professor of medicine at the University of Pittsburgh, and chief of infectious diseases at the Veterans Affairs Pittsburgh Healthcare System, echoed the concern.

“The casual belief has been that [C. difficile] strains at most centers can be assumed to be vancomycin susceptible,” he told this news organization. “This study shows that this assumption can no longer be taken as a given.”

Dr. Clancy, who was not involved with this research, noted that “based on this study, there might be need for the Infectious Diseases Society of America and other organizations to offer guidance on generating good, quality surveillance data for C. difficile resistance.”

With C. difficile showing the ability to resist multiple antibiotics, drugs in the armamentarium to treat the infection have declined in recent years, and recurrences with the infection are reported in up to 25% of cases.

Oral vancomycin is recommended as the antibiotic of choice by the IDSA and the Society for Healthcare Epidemiology of America for severe as well as nonsevere cases of CDI, and although there are reports of nine vancomycin-resistant gene clusters, most involve Enterococcus.

To take a closer look at the prevalence of vancomycin-resistant C. difficile strains, first author Charles Darkoh, PhD, with the Center for Infectious Diseases at the University of Texas Health Science Center, Houston, and colleagues analyzed stool samples from patients with CDI, including 438 patients in Houston, taken between 2012 and 2017, and 98 in Nairobi, Kenya, taken in 2017.

They found that, among samples from patients in Houston, over the time period, 26% showed vancomycin nonsusceptible C. difficile isolates and 29% had isolates that were metronidazole resistant.

And among samples from the Nairobi patients, 67% harbored vancomycin-resistant isolates and 85% had isolates resistant to metronidazole.

Of note, the proportion of samples containing vancomycin-resistant C. difficile in the Houston patients showed a marked increase over time, from «complete absence» in 2012 to approximately 35% in 2017, the authors reported.

“These nonsusceptibility rates significantly exceeded prior reports from other studies conducted in the United States and Europe from 2011 to 2014, suggesting a lower percentage of resistance to both metronidazole and vancomycin,” the authors wrote.

Further experiments on mouse models infected with one of the vancomycin-resistant isolates showed that treatment with vancomycin failed to eradicate the infection, and 5-day survival was significantly lower after vancomycin treatment in those mice (25%) versus those infected with strains known to be vancomycin sensitive (50%).
 

Unrecognized genetic strains

Whole-genome sequencing of 10 of the resistant isolates showed no matches with gene clusters that have been previously recognized as being vancomycin resistant, suggesting the emergence of new clusters.

“Together, these results suggest unknown genetic elements associated with vancomycin nonsusceptibility in isolates circulating in the patient population,” the authors wrote.

Dr. Darkoh told this news organization that the research team is currently working to further investigate the patterns and mechanisms.

“We are currently working on a follow-up study for the next 5 years to find out how widespread this is,” he said. “We want to make sure it’s not necessarily just occurring in the settings we studied, and we also need to establish the mechanism of resistance.”

Further commenting on the results, Dr. Clancy noted that “the extent of resistance caught many in the field a bit off guard, as they are higher than previously reported.”

“The data are also concerning because most centers do not routinely test C. difficile for drug susceptibility.”

Dr. Clancy noted that “another immediately pressing need is to understand mechanisms of resistance. It was quite striking that vancomycin-resistant strains in this study did not carry vanA genes, pointing to previously unrecognized mechanisms of resistance.”

“As is often the case, antibiotic overuse was likely a factor in the resistances, with overtesting often leading to overtreatment of C. difficile,” Dr. Clancy said. “The situation may have been compounded by failure to appreciate how entrenched C. difficile resistance may be at certain hospitals, since widespread susceptibility testing is generally not routinely performed.”

As alternative treatments, Dr. Clancy pointed to the recent IDSA update, which included a stronger endorsement of fidaxomicin.

“Of course, there is also the need to assure that data on resistance to agents like fidaxomicin are generated going forward,” he noted.

The study was supported by was supported by National Institutes of Health, the National Institute of Allergy and Infectious Diseases, the Texas Medical Center Digestive Diseases Center, and the University of Texas Health Science Center. Dr. Darkoh has disclosed no relevant financial relationships. One coauthor received grant support from Merck, Entasis Pharmaceuticals, and MeMed Diagnostics. Dr. Clancy disclosed advisory board, consulting and/or research relationships with Merck, Qpex Biopharma, Shionogi, Astellas, Cidara, Scynexis, and Needham & Associates.

A version of this article first appeared on Medscape.com.

Samples from patients in the United States and Kenya show an increasing emergence of previously undetected vancomycin-resistant strains of Clostridioides difficile, sparking concern as recurrences in the treatment of C. difficile infection (CDI) continue to rise.

“Our results may help explain a decreasing effectiveness of antibiotic-based therapy in C. difficile infection, since a significant proportion of patients harboring strains with reduced susceptibility to vancomycin may not respond to treatment,” reported the authors in research published recently in Clinical Infectious Diseases.

The spread of the resistant strains “has serious public health implications, underscoring an urgent need for a comprehensive analysis of the circulating strains to help inform clinical decisions,” they added.

Commenting on the findings, Cornelius J. Clancy, MD, professor of medicine at the University of Pittsburgh, and chief of infectious diseases at the Veterans Affairs Pittsburgh Healthcare System, echoed the concern.

“The casual belief has been that [C. difficile] strains at most centers can be assumed to be vancomycin susceptible,” he told this news organization. “This study shows that this assumption can no longer be taken as a given.”

Dr. Clancy, who was not involved with this research, noted that “based on this study, there might be need for the Infectious Diseases Society of America and other organizations to offer guidance on generating good, quality surveillance data for C. difficile resistance.”

With C. difficile showing the ability to resist multiple antibiotics, drugs in the armamentarium to treat the infection have declined in recent years, and recurrences with the infection are reported in up to 25% of cases.

Oral vancomycin is recommended as the antibiotic of choice by the IDSA and the Society for Healthcare Epidemiology of America for severe as well as nonsevere cases of CDI, and although there are reports of nine vancomycin-resistant gene clusters, most involve Enterococcus.

To take a closer look at the prevalence of vancomycin-resistant C. difficile strains, first author Charles Darkoh, PhD, with the Center for Infectious Diseases at the University of Texas Health Science Center, Houston, and colleagues analyzed stool samples from patients with CDI, including 438 patients in Houston, taken between 2012 and 2017, and 98 in Nairobi, Kenya, taken in 2017.

They found that, among samples from patients in Houston, over the time period, 26% showed vancomycin nonsusceptible C. difficile isolates and 29% had isolates that were metronidazole resistant.

And among samples from the Nairobi patients, 67% harbored vancomycin-resistant isolates and 85% had isolates resistant to metronidazole.

Of note, the proportion of samples containing vancomycin-resistant C. difficile in the Houston patients showed a marked increase over time, from «complete absence» in 2012 to approximately 35% in 2017, the authors reported.

“These nonsusceptibility rates significantly exceeded prior reports from other studies conducted in the United States and Europe from 2011 to 2014, suggesting a lower percentage of resistance to both metronidazole and vancomycin,” the authors wrote.

Further experiments on mouse models infected with one of the vancomycin-resistant isolates showed that treatment with vancomycin failed to eradicate the infection, and 5-day survival was significantly lower after vancomycin treatment in those mice (25%) versus those infected with strains known to be vancomycin sensitive (50%).
 

Unrecognized genetic strains

Whole-genome sequencing of 10 of the resistant isolates showed no matches with gene clusters that have been previously recognized as being vancomycin resistant, suggesting the emergence of new clusters.

“Together, these results suggest unknown genetic elements associated with vancomycin nonsusceptibility in isolates circulating in the patient population,” the authors wrote.

Dr. Darkoh told this news organization that the research team is currently working to further investigate the patterns and mechanisms.

“We are currently working on a follow-up study for the next 5 years to find out how widespread this is,” he said. “We want to make sure it’s not necessarily just occurring in the settings we studied, and we also need to establish the mechanism of resistance.”

Further commenting on the results, Dr. Clancy noted that “the extent of resistance caught many in the field a bit off guard, as they are higher than previously reported.”

“The data are also concerning because most centers do not routinely test C. difficile for drug susceptibility.”

Dr. Clancy noted that “another immediately pressing need is to understand mechanisms of resistance. It was quite striking that vancomycin-resistant strains in this study did not carry vanA genes, pointing to previously unrecognized mechanisms of resistance.”

“As is often the case, antibiotic overuse was likely a factor in the resistances, with overtesting often leading to overtreatment of C. difficile,” Dr. Clancy said. “The situation may have been compounded by failure to appreciate how entrenched C. difficile resistance may be at certain hospitals, since widespread susceptibility testing is generally not routinely performed.”

As alternative treatments, Dr. Clancy pointed to the recent IDSA update, which included a stronger endorsement of fidaxomicin.

“Of course, there is also the need to assure that data on resistance to agents like fidaxomicin are generated going forward,” he noted.

The study was supported by was supported by National Institutes of Health, the National Institute of Allergy and Infectious Diseases, the Texas Medical Center Digestive Diseases Center, and the University of Texas Health Science Center. Dr. Darkoh has disclosed no relevant financial relationships. One coauthor received grant support from Merck, Entasis Pharmaceuticals, and MeMed Diagnostics. Dr. Clancy disclosed advisory board, consulting and/or research relationships with Merck, Qpex Biopharma, Shionogi, Astellas, Cidara, Scynexis, and Needham & Associates.

A version of this article first appeared on Medscape.com.

Samples from patients in the United States and Kenya show an increasing emergence of previously undetected vancomycin-resistant strains of Clostridioides difficile, sparking concern as recurrences in the treatment of C. difficile infection (CDI) continue to rise.

“Our results may help explain a decreasing effectiveness of antibiotic-based therapy in C. difficile infection, since a significant proportion of patients harboring strains with reduced susceptibility to vancomycin may not respond to treatment,” reported the authors in research published recently in Clinical Infectious Diseases.

The spread of the resistant strains “has serious public health implications, underscoring an urgent need for a comprehensive analysis of the circulating strains to help inform clinical decisions,” they added.

Commenting on the findings, Cornelius J. Clancy, MD, professor of medicine at the University of Pittsburgh, and chief of infectious diseases at the Veterans Affairs Pittsburgh Healthcare System, echoed the concern.

“The casual belief has been that [C. difficile] strains at most centers can be assumed to be vancomycin susceptible,” he told this news organization. “This study shows that this assumption can no longer be taken as a given.”

Dr. Clancy, who was not involved with this research, noted that “based on this study, there might be need for the Infectious Diseases Society of America and other organizations to offer guidance on generating good, quality surveillance data for C. difficile resistance.”

With C. difficile showing the ability to resist multiple antibiotics, drugs in the armamentarium to treat the infection have declined in recent years, and recurrences with the infection are reported in up to 25% of cases.

Oral vancomycin is recommended as the antibiotic of choice by the IDSA and the Society for Healthcare Epidemiology of America for severe as well as nonsevere cases of CDI, and although there are reports of nine vancomycin-resistant gene clusters, most involve Enterococcus.

To take a closer look at the prevalence of vancomycin-resistant C. difficile strains, first author Charles Darkoh, PhD, with the Center for Infectious Diseases at the University of Texas Health Science Center, Houston, and colleagues analyzed stool samples from patients with CDI, including 438 patients in Houston, taken between 2012 and 2017, and 98 in Nairobi, Kenya, taken in 2017.

They found that, among samples from patients in Houston, over the time period, 26% showed vancomycin nonsusceptible C. difficile isolates and 29% had isolates that were metronidazole resistant.

And among samples from the Nairobi patients, 67% harbored vancomycin-resistant isolates and 85% had isolates resistant to metronidazole.

Of note, the proportion of samples containing vancomycin-resistant C. difficile in the Houston patients showed a marked increase over time, from «complete absence» in 2012 to approximately 35% in 2017, the authors reported.

“These nonsusceptibility rates significantly exceeded prior reports from other studies conducted in the United States and Europe from 2011 to 2014, suggesting a lower percentage of resistance to both metronidazole and vancomycin,” the authors wrote.

Further experiments on mouse models infected with one of the vancomycin-resistant isolates showed that treatment with vancomycin failed to eradicate the infection, and 5-day survival was significantly lower after vancomycin treatment in those mice (25%) versus those infected with strains known to be vancomycin sensitive (50%).
 

Unrecognized genetic strains

Whole-genome sequencing of 10 of the resistant isolates showed no matches with gene clusters that have been previously recognized as being vancomycin resistant, suggesting the emergence of new clusters.

“Together, these results suggest unknown genetic elements associated with vancomycin nonsusceptibility in isolates circulating in the patient population,” the authors wrote.

Dr. Darkoh told this news organization that the research team is currently working to further investigate the patterns and mechanisms.

“We are currently working on a follow-up study for the next 5 years to find out how widespread this is,” he said. “We want to make sure it’s not necessarily just occurring in the settings we studied, and we also need to establish the mechanism of resistance.”

Further commenting on the results, Dr. Clancy noted that “the extent of resistance caught many in the field a bit off guard, as they are higher than previously reported.”

“The data are also concerning because most centers do not routinely test C. difficile for drug susceptibility.”

Dr. Clancy noted that “another immediately pressing need is to understand mechanisms of resistance. It was quite striking that vancomycin-resistant strains in this study did not carry vanA genes, pointing to previously unrecognized mechanisms of resistance.”

“As is often the case, antibiotic overuse was likely a factor in the resistances, with overtesting often leading to overtreatment of C. difficile,” Dr. Clancy said. “The situation may have been compounded by failure to appreciate how entrenched C. difficile resistance may be at certain hospitals, since widespread susceptibility testing is generally not routinely performed.”

As alternative treatments, Dr. Clancy pointed to the recent IDSA update, which included a stronger endorsement of fidaxomicin.

“Of course, there is also the need to assure that data on resistance to agents like fidaxomicin are generated going forward,” he noted.

The study was supported by was supported by National Institutes of Health, the National Institute of Allergy and Infectious Diseases, the Texas Medical Center Digestive Diseases Center, and the University of Texas Health Science Center. Dr. Darkoh has disclosed no relevant financial relationships. One coauthor received grant support from Merck, Entasis Pharmaceuticals, and MeMed Diagnostics. Dr. Clancy disclosed advisory board, consulting and/or research relationships with Merck, Qpex Biopharma, Shionogi, Astellas, Cidara, Scynexis, and Needham & Associates.

A version of this article first appeared on Medscape.com.

Bronchiolitis is the leading cause of infant hospitalizations in the United States and Europe, and almost one-third of these patients go on to develop asthma later in childhood.

But a multinational team of researchers has presented evidence that could avoid that outcome. They identified four different subtypes of bronchiolitis along with a decision tree that can determine which infants are most likely to develop asthma as they get older.

Reporting in the journal eClinical Medicine, Michimasa Fujiogi, MD, of Massachusetts General Hospital and Harvard University, Boston, and colleagues analyzed three multicenter prospective cohort studies that included a combined 3,081 infants hospitalized with severe bronchiolitis.

“This study added a base for the early identification of high-risk patients during early infancy,” Dr. Fujiogi said in an interview. “Using the prediction rule of this study, it is possible to identify groups at high risk of asthma during a critical period of airway development – early infancy.”

The researchers identified four clinically distinct and reproducible profiles of infants hospitalized for bronchiolitis:

• A: characterized by a history of breathing problems and eczema, rhinovirus infection, and low prevalence of respiratory syncytial virus (RSV) infection.
• B: characterized by the classic symptoms of wheezing and cough at presentation, a low prevalence of previous breathing problems and rhinovirus infection, and a high likelihood of RSV infection.
• C: the most severe group, characterized by inadequate oral intake, severe retraction at presentation, and longer hospital stays.
• D: the least ill group, with little history of breathing problems but inadequate oral intake with no or mild retraction.

Infants with profile A had the highest risk for developing asthma – more than 250% greater than with typical bronchiolitis. They were also older and were more likely to have parents who had asthma – and none had solo-RSV infection. In the overall analysis, the risk for developing asthma by age 6 or 7 was 23%.

The researchers stated that the decision tree accurately predicts the high-risk profile with high degrees of sensitivity and specificity. The decision tree used four predictors that together defined infants with profile A: RSV infection status, previous breathing problems, eczema, and parental asthma.

“Our data would facilitate the development of profile-specific prevention strategies for asthma – for example, modification of host response, prophylaxis for severe viral infection – by identifying asthma risk groups early in infancy,” Dr. Fujiogi said.

The study received funding from the National Institutes of Health. Dr. Fujiogi and coauthors have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Bronchiolitis is the leading cause of infant hospitalizations in the United States and Europe, and almost one-third of these patients go on to develop asthma later in childhood.

But a multinational team of researchers has presented evidence that could avoid that outcome. They identified four different subtypes of bronchiolitis along with a decision tree that can determine which infants are most likely to develop asthma as they get older.

Reporting in the journal eClinical Medicine, Michimasa Fujiogi, MD, of Massachusetts General Hospital and Harvard University, Boston, and colleagues analyzed three multicenter prospective cohort studies that included a combined 3,081 infants hospitalized with severe bronchiolitis.

“This study added a base for the early identification of high-risk patients during early infancy,” Dr. Fujiogi said in an interview. “Using the prediction rule of this study, it is possible to identify groups at high risk of asthma during a critical period of airway development – early infancy.”

The researchers identified four clinically distinct and reproducible profiles of infants hospitalized for bronchiolitis:

• A: characterized by a history of breathing problems and eczema, rhinovirus infection, and low prevalence of respiratory syncytial virus (RSV) infection.
• B: characterized by the classic symptoms of wheezing and cough at presentation, a low prevalence of previous breathing problems and rhinovirus infection, and a high likelihood of RSV infection.
• C: the most severe group, characterized by inadequate oral intake, severe retraction at presentation, and longer hospital stays.
• D: the least ill group, with little history of breathing problems but inadequate oral intake with no or mild retraction.

Infants with profile A had the highest risk for developing asthma – more than 250% greater than with typical bronchiolitis. They were also older and were more likely to have parents who had asthma – and none had solo-RSV infection. In the overall analysis, the risk for developing asthma by age 6 or 7 was 23%.

The researchers stated that the decision tree accurately predicts the high-risk profile with high degrees of sensitivity and specificity. The decision tree used four predictors that together defined infants with profile A: RSV infection status, previous breathing problems, eczema, and parental asthma.

“Our data would facilitate the development of profile-specific prevention strategies for asthma – for example, modification of host response, prophylaxis for severe viral infection – by identifying asthma risk groups early in infancy,” Dr. Fujiogi said.

The study received funding from the National Institutes of Health. Dr. Fujiogi and coauthors have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Bronchiolitis is the leading cause of infant hospitalizations in the United States and Europe, and almost one-third of these patients go on to develop asthma later in childhood.

But a multinational team of researchers has presented evidence that could avoid that outcome. They identified four different subtypes of bronchiolitis along with a decision tree that can determine which infants are most likely to develop asthma as they get older.

Reporting in the journal eClinical Medicine, Michimasa Fujiogi, MD, of Massachusetts General Hospital and Harvard University, Boston, and colleagues analyzed three multicenter prospective cohort studies that included a combined 3,081 infants hospitalized with severe bronchiolitis.

“This study added a base for the early identification of high-risk patients during early infancy,” Dr. Fujiogi said in an interview. “Using the prediction rule of this study, it is possible to identify groups at high risk of asthma during a critical period of airway development – early infancy.”

The researchers identified four clinically distinct and reproducible profiles of infants hospitalized for bronchiolitis:

• A: characterized by a history of breathing problems and eczema, rhinovirus infection, and low prevalence of respiratory syncytial virus (RSV) infection.
• B: characterized by the classic symptoms of wheezing and cough at presentation, a low prevalence of previous breathing problems and rhinovirus infection, and a high likelihood of RSV infection.
• C: the most severe group, characterized by inadequate oral intake, severe retraction at presentation, and longer hospital stays.
• D: the least ill group, with little history of breathing problems but inadequate oral intake with no or mild retraction.

Infants with profile A had the highest risk for developing asthma – more than 250% greater than with typical bronchiolitis. They were also older and were more likely to have parents who had asthma – and none had solo-RSV infection. In the overall analysis, the risk for developing asthma by age 6 or 7 was 23%.

The researchers stated that the decision tree accurately predicts the high-risk profile with high degrees of sensitivity and specificity. The decision tree used four predictors that together defined infants with profile A: RSV infection status, previous breathing problems, eczema, and parental asthma.

“Our data would facilitate the development of profile-specific prevention strategies for asthma – for example, modification of host response, prophylaxis for severe viral infection – by identifying asthma risk groups early in infancy,” Dr. Fujiogi said.

The study received funding from the National Institutes of Health. Dr. Fujiogi and coauthors have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Vaginal cleansing showed no reduction in morbidity when performed before unscheduled cesarean deliveries, researchers reported at the 2022 Pregnancy Meeting of the Society for Maternal-Fetal Medicine.

Several studies have evaluated vaginal cleansing prior to cesarean delivery, with mixed results. The American College of Obstetricians and Gynecologists recommends clinicians consider cleansing prior to unscheduled cesareans, but that advice appears not to be widely heeded.

The new findings, from what the researchers called the single largest study of vaginal cleansing prior to cesarean delivery in the United States, showed no difference in post-cesarean infections when the vagina was cleansed with povidone-iodine prior to unscheduled cesarean delivery.

“These findings do not support routine vaginal cleansing prior to unscheduled cesarean deliveries,” lead author Lorene Atkins Temming, MD, medical director of labor and delivery at Atrium Health Wake Forest School of Medicine, Charlotte, North Carolina, told this news organization. The research was conducted at and sponsored by Washington University School of Medicine, St. Louis, where Dr. Temming did her fellowship.

Dr. Temming’s group compared vaginal cleansing with povidone-iodine in addition to routine abdominal cleansing to abdominal cleansing alone. Among the primary outcomes of the study was the effect of cleansing on post-cesarean infectious morbidity.

“There is a higher risk of infectious complications after cesarean delivery than other gynecologic surgeries,” Dr. Temming told this news organization. “While the reason for this isn’t entirely clear, it is thought to be because cesareans are often performed after a patient’s cervix is dilated. This dilation can allow normal bacteria that live in the vagina to ascend into the uterus and can increase the risk of infections.”

Patients undergoing cesarean delivery after labor were randomly assigned to undergo preoperative abdominal cleansing only (n = 304) or preoperative abdominal cleansing plus vaginal cleansing with povidone-iodine (n = 304). Women were included in the analysis if they underwent cesareans after regular contractions and any cervical dilation, if their membranes ruptured, or if they had the procedure performed when they were more than 4 cm dilated.

The primary outcome was composite infectious morbidity, a catchall that included surgical-site infection, maternal fever, endometritis, and wound complications within 30 days after cesarean delivery. The secondary outcomes were hospital readmission, visits to the emergency department, and treatment for neonatal sepsis.

The researchers observed no significant difference in the primary composite outcome between the two groups (11.7% vs. 11.7%, P = .98; 95% confidence interval, 0.6-1.5). “Vaginal cleansing appears to be unnecessary when preoperative antibiotics and skin antisepsis are performed,” Dr. Temming said.

Jennifer L. Lew, MD, an ob/gyn at Northwestern Medicine Kishwaukee Hospital in Dekalb, Illinois, said current practice regarding preparation for unscheduled cesarean surgery includes chlorhexidine on the abdomen and povidone-iodine for introducing a Foley catheter into the urethra.

“Many patients may already have a catheter in place due to labor and epidural, so they would not need” vaginal prep, Dr. Lew said. “Currently, the standard does not require doing a vaginal prep for any cesarean sections, those in labor or not.”

The researchers have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Vaginal cleansing showed no reduction in morbidity when performed before unscheduled cesarean deliveries, researchers reported at the 2022 Pregnancy Meeting of the Society for Maternal-Fetal Medicine.

Several studies have evaluated vaginal cleansing prior to cesarean delivery, with mixed results. The American College of Obstetricians and Gynecologists recommends clinicians consider cleansing prior to unscheduled cesareans, but that advice appears not to be widely heeded.

The new findings, from what the researchers called the single largest study of vaginal cleansing prior to cesarean delivery in the United States, showed no difference in post-cesarean infections when the vagina was cleansed with povidone-iodine prior to unscheduled cesarean delivery.

“These findings do not support routine vaginal cleansing prior to unscheduled cesarean deliveries,” lead author Lorene Atkins Temming, MD, medical director of labor and delivery at Atrium Health Wake Forest School of Medicine, Charlotte, North Carolina, told this news organization. The research was conducted at and sponsored by Washington University School of Medicine, St. Louis, where Dr. Temming did her fellowship.

Dr. Temming’s group compared vaginal cleansing with povidone-iodine in addition to routine abdominal cleansing to abdominal cleansing alone. Among the primary outcomes of the study was the effect of cleansing on post-cesarean infectious morbidity.

“There is a higher risk of infectious complications after cesarean delivery than other gynecologic surgeries,” Dr. Temming told this news organization. “While the reason for this isn’t entirely clear, it is thought to be because cesareans are often performed after a patient’s cervix is dilated. This dilation can allow normal bacteria that live in the vagina to ascend into the uterus and can increase the risk of infections.”

Patients undergoing cesarean delivery after labor were randomly assigned to undergo preoperative abdominal cleansing only (n = 304) or preoperative abdominal cleansing plus vaginal cleansing with povidone-iodine (n = 304). Women were included in the analysis if they underwent cesareans after regular contractions and any cervical dilation, if their membranes ruptured, or if they had the procedure performed when they were more than 4 cm dilated.

The primary outcome was composite infectious morbidity, a catchall that included surgical-site infection, maternal fever, endometritis, and wound complications within 30 days after cesarean delivery. The secondary outcomes were hospital readmission, visits to the emergency department, and treatment for neonatal sepsis.

The researchers observed no significant difference in the primary composite outcome between the two groups (11.7% vs. 11.7%, P = .98; 95% confidence interval, 0.6-1.5). “Vaginal cleansing appears to be unnecessary when preoperative antibiotics and skin antisepsis are performed,” Dr. Temming said.

Jennifer L. Lew, MD, an ob/gyn at Northwestern Medicine Kishwaukee Hospital in Dekalb, Illinois, said current practice regarding preparation for unscheduled cesarean surgery includes chlorhexidine on the abdomen and povidone-iodine for introducing a Foley catheter into the urethra.

“Many patients may already have a catheter in place due to labor and epidural, so they would not need” vaginal prep, Dr. Lew said. “Currently, the standard does not require doing a vaginal prep for any cesarean sections, those in labor or not.”

The researchers have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Vaginal cleansing showed no reduction in morbidity when performed before unscheduled cesarean deliveries, researchers reported at the 2022 Pregnancy Meeting of the Society for Maternal-Fetal Medicine.

Several studies have evaluated vaginal cleansing prior to cesarean delivery, with mixed results. The American College of Obstetricians and Gynecologists recommends clinicians consider cleansing prior to unscheduled cesareans, but that advice appears not to be widely heeded.

The new findings, from what the researchers called the single largest study of vaginal cleansing prior to cesarean delivery in the United States, showed no difference in post-cesarean infections when the vagina was cleansed with povidone-iodine prior to unscheduled cesarean delivery.

“These findings do not support routine vaginal cleansing prior to unscheduled cesarean deliveries,” lead author Lorene Atkins Temming, MD, medical director of labor and delivery at Atrium Health Wake Forest School of Medicine, Charlotte, North Carolina, told this news organization. The research was conducted at and sponsored by Washington University School of Medicine, St. Louis, where Dr. Temming did her fellowship.

Dr. Temming’s group compared vaginal cleansing with povidone-iodine in addition to routine abdominal cleansing to abdominal cleansing alone. Among the primary outcomes of the study was the effect of cleansing on post-cesarean infectious morbidity.

“There is a higher risk of infectious complications after cesarean delivery than other gynecologic surgeries,” Dr. Temming told this news organization. “While the reason for this isn’t entirely clear, it is thought to be because cesareans are often performed after a patient’s cervix is dilated. This dilation can allow normal bacteria that live in the vagina to ascend into the uterus and can increase the risk of infections.”

Patients undergoing cesarean delivery after labor were randomly assigned to undergo preoperative abdominal cleansing only (n = 304) or preoperative abdominal cleansing plus vaginal cleansing with povidone-iodine (n = 304). Women were included in the analysis if they underwent cesareans after regular contractions and any cervical dilation, if their membranes ruptured, or if they had the procedure performed when they were more than 4 cm dilated.

The primary outcome was composite infectious morbidity, a catchall that included surgical-site infection, maternal fever, endometritis, and wound complications within 30 days after cesarean delivery. The secondary outcomes were hospital readmission, visits to the emergency department, and treatment for neonatal sepsis.

The researchers observed no significant difference in the primary composite outcome between the two groups (11.7% vs. 11.7%, P = .98; 95% confidence interval, 0.6-1.5). “Vaginal cleansing appears to be unnecessary when preoperative antibiotics and skin antisepsis are performed,” Dr. Temming said.

Jennifer L. Lew, MD, an ob/gyn at Northwestern Medicine Kishwaukee Hospital in Dekalb, Illinois, said current practice regarding preparation for unscheduled cesarean surgery includes chlorhexidine on the abdomen and povidone-iodine for introducing a Foley catheter into the urethra.

“Many patients may already have a catheter in place due to labor and epidural, so they would not need” vaginal prep, Dr. Lew said. “Currently, the standard does not require doing a vaginal prep for any cesarean sections, those in labor or not.”

The researchers have disclosed no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The Diagnosis: Kaposi Sarcoma

A punch biopsy of a lesion on the right side of the back revealed a diffuse, poorly circumscribed, spindle cell neoplasm of the papillary and reticular dermis with associated vascular and pseudovascular spaces distended by erythrocytes (Figure 1). Immunostaining was positive for human herpesvirus 8 (HHV-8)(Figure 2), ETS-related gene, CD31, and CD34 and negative for pan cytokeratin, confirming the diagnosis of Kaposi sarcoma (KS). Bacterial, fungal, and mycobacterial tissue cultures were negative. The patient was tested for HIV and referred to infectious disease and oncology. He subsequently was found to have HIV with a viral load greater than 1 million copies. He was started on antiretroviral therapy and Pneumocystis jirovecii pneumonia prophylaxis. Computed tomography of the chest, abdomen, and pelvis showed bilateral, multifocal, perihilar, flame-shaped consolidations suggestive of KS. The patient later disclosed having an intermittent dry cough of more than a year’s duration with occasional bright red blood per rectum after bowel movements. After workup, the patient was found to have cytomegalovirus esophagitis/gastritis and candidal esophagitis that were treated with valganciclovir and fluconazole, respectively.

Kaposi sarcoma is an angioproliferative, AIDSdefining disease associated with HHV-8. There are 4 types of KS as defined by the populations they affect. AIDS-associated KS occurs in individuals with HIV, as seen in our patient. It often is accompanied by extensive mucocutaneous and visceral lesions, as well as systemic symptoms such as fever, weight loss, and diarrhea.¹ Classic KS is a variant that presents in older men of Mediterranean, Eastern European, and South American descent. Cutaneous lesions typically are distributed on the lower extremities.^2,3 Endemic (African) KS is seen in HIV-negative children and young adults in equatorial Africa. It most commonly affects the lower extremities or lymph nodes and usually follows a more aggressive course.² Lastly, iatrogenic KS is associated with immunosuppressive medications or conditions, such as organ transplantation, chemotherapy, and rheumatologic disorders.^3,4

Kaposi sarcoma commonly presents as violaceous or dark red macules, patches, papules, plaques, and nodules on various parts of the body (Figure 3). Lesions typically begin as macules and progress into plaques or nodules. Our patient presented as a deceptively healthy young man with lesions at various stages of development. In addition to the skin and oral mucosa, the lungs, lymph nodes, and gastrointestinal tract commonly are involved in AIDS-associated KS.⁵ Patients may experience symptoms of internal involvement, including bleeding, hematochezia, odynophagia, or dyspnea.

The differential diagnosis includes conditions that can mimic KS, including bacillary angiomatosis, angioinvasive fungal disease, sarcoid, and other malignancies. A skin biopsy is the gold standard for definitive diagnosis of KS. Histopathology shows a vascular proliferation in the dermis and spindle cell proliferation.⁶ Kaposi sarcoma stains positively for factor VIII–related antigen, CD31, and CD34.² Additionally, staining for HHV-8 gene products, such as latency-associated nuclear antigen 1, is helpful in differentiating KS from other conditions.⁷

In HIV-associated KS, the mainstay of treatment is initiation of highly active antiretroviral therapy. Typically, as the CD4 count rises with treatment, the tumor burden classic KS, effective treatment options include recurrent cryotherapy or intralesional chemotherapeutics, such as vincristine, for localized lesions; for widespread disease, pegylated liposomal doxorubicin or radiation have been found to be effective options. Lastly, for patients with iatrogenic KS, reducing immunosuppressive medications is a reasonable first step in management. If this does not yield adequate improvement, transitioning from calcineurin inhibitors (eg, cyclosporine) to proliferation signal inhibitors (eg, sirolimus) may lead to resolution.⁷

The Diagnosis: Kaposi Sarcoma

A punch biopsy of a lesion on the right side of the back revealed a diffuse, poorly circumscribed, spindle cell neoplasm of the papillary and reticular dermis with associated vascular and pseudovascular spaces distended by erythrocytes (Figure 1). Immunostaining was positive for human herpesvirus 8 (HHV-8)(Figure 2), ETS-related gene, CD31, and CD34 and negative for pan cytokeratin, confirming the diagnosis of Kaposi sarcoma (KS). Bacterial, fungal, and mycobacterial tissue cultures were negative. The patient was tested for HIV and referred to infectious disease and oncology. He subsequently was found to have HIV with a viral load greater than 1 million copies. He was started on antiretroviral therapy and Pneumocystis jirovecii pneumonia prophylaxis. Computed tomography of the chest, abdomen, and pelvis showed bilateral, multifocal, perihilar, flame-shaped consolidations suggestive of KS. The patient later disclosed having an intermittent dry cough of more than a year’s duration with occasional bright red blood per rectum after bowel movements. After workup, the patient was found to have cytomegalovirus esophagitis/gastritis and candidal esophagitis that were treated with valganciclovir and fluconazole, respectively.

Kaposi sarcoma is an angioproliferative, AIDSdefining disease associated with HHV-8. There are 4 types of KS as defined by the populations they affect. AIDS-associated KS occurs in individuals with HIV, as seen in our patient. It often is accompanied by extensive mucocutaneous and visceral lesions, as well as systemic symptoms such as fever, weight loss, and diarrhea.¹ Classic KS is a variant that presents in older men of Mediterranean, Eastern European, and South American descent. Cutaneous lesions typically are distributed on the lower extremities.^2,3 Endemic (African) KS is seen in HIV-negative children and young adults in equatorial Africa. It most commonly affects the lower extremities or lymph nodes and usually follows a more aggressive course.² Lastly, iatrogenic KS is associated with immunosuppressive medications or conditions, such as organ transplantation, chemotherapy, and rheumatologic disorders.^3,4

Kaposi sarcoma commonly presents as violaceous or dark red macules, patches, papules, plaques, and nodules on various parts of the body (Figure 3). Lesions typically begin as macules and progress into plaques or nodules. Our patient presented as a deceptively healthy young man with lesions at various stages of development. In addition to the skin and oral mucosa, the lungs, lymph nodes, and gastrointestinal tract commonly are involved in AIDS-associated KS.⁵ Patients may experience symptoms of internal involvement, including bleeding, hematochezia, odynophagia, or dyspnea.

The differential diagnosis includes conditions that can mimic KS, including bacillary angiomatosis, angioinvasive fungal disease, sarcoid, and other malignancies. A skin biopsy is the gold standard for definitive diagnosis of KS. Histopathology shows a vascular proliferation in the dermis and spindle cell proliferation.⁶ Kaposi sarcoma stains positively for factor VIII–related antigen, CD31, and CD34.² Additionally, staining for HHV-8 gene products, such as latency-associated nuclear antigen 1, is helpful in differentiating KS from other conditions.⁷

In HIV-associated KS, the mainstay of treatment is initiation of highly active antiretroviral therapy. Typically, as the CD4 count rises with treatment, the tumor burden classic KS, effective treatment options include recurrent cryotherapy or intralesional chemotherapeutics, such as vincristine, for localized lesions; for widespread disease, pegylated liposomal doxorubicin or radiation have been found to be effective options. Lastly, for patients with iatrogenic KS, reducing immunosuppressive medications is a reasonable first step in management. If this does not yield adequate improvement, transitioning from calcineurin inhibitors (eg, cyclosporine) to proliferation signal inhibitors (eg, sirolimus) may lead to resolution.⁷

The Diagnosis: Kaposi Sarcoma

A punch biopsy of a lesion on the right side of the back revealed a diffuse, poorly circumscribed, spindle cell neoplasm of the papillary and reticular dermis with associated vascular and pseudovascular spaces distended by erythrocytes (Figure 1). Immunostaining was positive for human herpesvirus 8 (HHV-8)(Figure 2), ETS-related gene, CD31, and CD34 and negative for pan cytokeratin, confirming the diagnosis of Kaposi sarcoma (KS). Bacterial, fungal, and mycobacterial tissue cultures were negative. The patient was tested for HIV and referred to infectious disease and oncology. He subsequently was found to have HIV with a viral load greater than 1 million copies. He was started on antiretroviral therapy and Pneumocystis jirovecii pneumonia prophylaxis. Computed tomography of the chest, abdomen, and pelvis showed bilateral, multifocal, perihilar, flame-shaped consolidations suggestive of KS. The patient later disclosed having an intermittent dry cough of more than a year’s duration with occasional bright red blood per rectum after bowel movements. After workup, the patient was found to have cytomegalovirus esophagitis/gastritis and candidal esophagitis that were treated with valganciclovir and fluconazole, respectively.

Kaposi sarcoma is an angioproliferative, AIDSdefining disease associated with HHV-8. There are 4 types of KS as defined by the populations they affect. AIDS-associated KS occurs in individuals with HIV, as seen in our patient. It often is accompanied by extensive mucocutaneous and visceral lesions, as well as systemic symptoms such as fever, weight loss, and diarrhea.¹ Classic KS is a variant that presents in older men of Mediterranean, Eastern European, and South American descent. Cutaneous lesions typically are distributed on the lower extremities.^2,3 Endemic (African) KS is seen in HIV-negative children and young adults in equatorial Africa. It most commonly affects the lower extremities or lymph nodes and usually follows a more aggressive course.² Lastly, iatrogenic KS is associated with immunosuppressive medications or conditions, such as organ transplantation, chemotherapy, and rheumatologic disorders.^3,4

Kaposi sarcoma commonly presents as violaceous or dark red macules, patches, papules, plaques, and nodules on various parts of the body (Figure 3). Lesions typically begin as macules and progress into plaques or nodules. Our patient presented as a deceptively healthy young man with lesions at various stages of development. In addition to the skin and oral mucosa, the lungs, lymph nodes, and gastrointestinal tract commonly are involved in AIDS-associated KS.⁵ Patients may experience symptoms of internal involvement, including bleeding, hematochezia, odynophagia, or dyspnea.

The differential diagnosis includes conditions that can mimic KS, including bacillary angiomatosis, angioinvasive fungal disease, sarcoid, and other malignancies. A skin biopsy is the gold standard for definitive diagnosis of KS. Histopathology shows a vascular proliferation in the dermis and spindle cell proliferation.⁶ Kaposi sarcoma stains positively for factor VIII–related antigen, CD31, and CD34.² Additionally, staining for HHV-8 gene products, such as latency-associated nuclear antigen 1, is helpful in differentiating KS from other conditions.⁷

In HIV-associated KS, the mainstay of treatment is initiation of highly active antiretroviral therapy. Typically, as the CD4 count rises with treatment, the tumor burden classic KS, effective treatment options include recurrent cryotherapy or intralesional chemotherapeutics, such as vincristine, for localized lesions; for widespread disease, pegylated liposomal doxorubicin or radiation have been found to be effective options. Lastly, for patients with iatrogenic KS, reducing immunosuppressive medications is a reasonable first step in management. If this does not yield adequate improvement, transitioning from calcineurin inhibitors (eg, cyclosporine) to proliferation signal inhibitors (eg, sirolimus) may lead to resolution.⁷

It seems obvious that increased use of mosquito bed nets in sub-Saharan Africa would decrease the incidence of malaria, but a lingering question remained: Would controlling malaria in children under 5 years of age shift deaths to older children by delaying functional immunity?  A new report in the New England Journal of Medicine seems to have laid that concern to rest.

Malaria from Plasmodium falciparum infection exacts a significant toll in sub-Saharan Africa. According to the World Health Organization, there were about 228 million cases and 602,000 deaths from malaria in 2020 alone. About 80% of those deaths were in children less than 5 years old. In some areas, as many as 5% of children die from malaria by age 5.

Efforts to reduce the burden of malaria have been ongoing for decades. In the 1990s, insecticide-treated nets were shown to reduce illness and deaths from malaria in children.

As a result, the use of bed nets has grown significantly. In 2000, only 5% of households in sub-Saharan Africa had a net in the house. By 2020, that number had risen to 65%. From 2004 to 2019 about 1.9 billion nets were distributed in this region. The nets are estimated to have prevented more than 663 million malaria cases between 2000 and 2015.

As described in the NEJM report, public health researchers conducted a 22-year prospective longitudinal cohort study in rural southern Tanzania following 6,706 children born between 1998 and 2000. Initially, home visits were made every 4 months from May 1998 to April 2003. Remarkably, in 2019, they were able to verify the status of fully 89% of those people by reaching out to families and community/village leaders.

Günther Fink, PhD, associate professor of epidemiology and household economics, University of Basel (Switzerland), explained the approach and primary findings to this news organization. The analysis looked at three main groups – children whose parents said they always slept under treated nets, those who slept protected most of the time, and those who spent less than half the time under bed nets. The hazard ratio for death was 0.57 (95% confidence interval, 0.45-0.72) for the first two groups, compared with the least protected. The corresponding hazard ratio between age 5 and adulthood was 0.93 (95% CI, 0.58-1.49).

The findings confirmed what they had suspected. Dr. Fink summarized simply, “If you always slept under a net, you did much better than if you never slept under the net. If you slept [under a net] more than half of the time, it was much better than if you slept [under a net] less than half the time.” So the more time children slept under bed nets, the less likely they were to acquire malaria. Dr. Fink stressed that the findings showing protective efficacy persisted into adulthood. “It seems just having a healthier early life actually makes you more resilient against other future infections.”

One of the theoretical concerns was that using nets would delay developing functional immunity and that there might be an increase in mortality seen later. This study showed that did not happen.

An accompanying commentary noted that there was some potential that families receiving nets were better off than those that didn’t but concluded that such confounding had been accounted for in other analyses.

Mark Wilson, ScD, professor emeritus of epidemiology, University of Michigan, Ann Arbor, concurred. He told this news organization that the study was “very well designed,” and the researchers “did a fantastic job” in tracking patients 20 years later.

“This is astounding!” he added. “It’s very rare to find this amount of follow-up.”

Dr. Fink’s conclusion? “Bed nets protect you in the short run, and being protected in the short run is also beneficial in the long run. There is no evidence that protecting kids in early childhood is weakening them in any way. So we should keep doing this.”

Dr. Fink and Dr. Wilson report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

It seems obvious that increased use of mosquito bed nets in sub-Saharan Africa would decrease the incidence of malaria, but a lingering question remained: Would controlling malaria in children under 5 years of age shift deaths to older children by delaying functional immunity?  A new report in the New England Journal of Medicine seems to have laid that concern to rest.

Malaria from Plasmodium falciparum infection exacts a significant toll in sub-Saharan Africa. According to the World Health Organization, there were about 228 million cases and 602,000 deaths from malaria in 2020 alone. About 80% of those deaths were in children less than 5 years old. In some areas, as many as 5% of children die from malaria by age 5.

Efforts to reduce the burden of malaria have been ongoing for decades. In the 1990s, insecticide-treated nets were shown to reduce illness and deaths from malaria in children.

As a result, the use of bed nets has grown significantly. In 2000, only 5% of households in sub-Saharan Africa had a net in the house. By 2020, that number had risen to 65%. From 2004 to 2019 about 1.9 billion nets were distributed in this region. The nets are estimated to have prevented more than 663 million malaria cases between 2000 and 2015.

As described in the NEJM report, public health researchers conducted a 22-year prospective longitudinal cohort study in rural southern Tanzania following 6,706 children born between 1998 and 2000. Initially, home visits were made every 4 months from May 1998 to April 2003. Remarkably, in 2019, they were able to verify the status of fully 89% of those people by reaching out to families and community/village leaders.

Günther Fink, PhD, associate professor of epidemiology and household economics, University of Basel (Switzerland), explained the approach and primary findings to this news organization. The analysis looked at three main groups – children whose parents said they always slept under treated nets, those who slept protected most of the time, and those who spent less than half the time under bed nets. The hazard ratio for death was 0.57 (95% confidence interval, 0.45-0.72) for the first two groups, compared with the least protected. The corresponding hazard ratio between age 5 and adulthood was 0.93 (95% CI, 0.58-1.49).

The findings confirmed what they had suspected. Dr. Fink summarized simply, “If you always slept under a net, you did much better than if you never slept under the net. If you slept [under a net] more than half of the time, it was much better than if you slept [under a net] less than half the time.” So the more time children slept under bed nets, the less likely they were to acquire malaria. Dr. Fink stressed that the findings showing protective efficacy persisted into adulthood. “It seems just having a healthier early life actually makes you more resilient against other future infections.”

One of the theoretical concerns was that using nets would delay developing functional immunity and that there might be an increase in mortality seen later. This study showed that did not happen.

An accompanying commentary noted that there was some potential that families receiving nets were better off than those that didn’t but concluded that such confounding had been accounted for in other analyses.

Mark Wilson, ScD, professor emeritus of epidemiology, University of Michigan, Ann Arbor, concurred. He told this news organization that the study was “very well designed,” and the researchers “did a fantastic job” in tracking patients 20 years later.

“This is astounding!” he added. “It’s very rare to find this amount of follow-up.”

Dr. Fink’s conclusion? “Bed nets protect you in the short run, and being protected in the short run is also beneficial in the long run. There is no evidence that protecting kids in early childhood is weakening them in any way. So we should keep doing this.”

Dr. Fink and Dr. Wilson report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

It seems obvious that increased use of mosquito bed nets in sub-Saharan Africa would decrease the incidence of malaria, but a lingering question remained: Would controlling malaria in children under 5 years of age shift deaths to older children by delaying functional immunity?  A new report in the New England Journal of Medicine seems to have laid that concern to rest.

Malaria from Plasmodium falciparum infection exacts a significant toll in sub-Saharan Africa. According to the World Health Organization, there were about 228 million cases and 602,000 deaths from malaria in 2020 alone. About 80% of those deaths were in children less than 5 years old. In some areas, as many as 5% of children die from malaria by age 5.

Efforts to reduce the burden of malaria have been ongoing for decades. In the 1990s, insecticide-treated nets were shown to reduce illness and deaths from malaria in children.

As a result, the use of bed nets has grown significantly. In 2000, only 5% of households in sub-Saharan Africa had a net in the house. By 2020, that number had risen to 65%. From 2004 to 2019 about 1.9 billion nets were distributed in this region. The nets are estimated to have prevented more than 663 million malaria cases between 2000 and 2015.

As described in the NEJM report, public health researchers conducted a 22-year prospective longitudinal cohort study in rural southern Tanzania following 6,706 children born between 1998 and 2000. Initially, home visits were made every 4 months from May 1998 to April 2003. Remarkably, in 2019, they were able to verify the status of fully 89% of those people by reaching out to families and community/village leaders.

Günther Fink, PhD, associate professor of epidemiology and household economics, University of Basel (Switzerland), explained the approach and primary findings to this news organization. The analysis looked at three main groups – children whose parents said they always slept under treated nets, those who slept protected most of the time, and those who spent less than half the time under bed nets. The hazard ratio for death was 0.57 (95% confidence interval, 0.45-0.72) for the first two groups, compared with the least protected. The corresponding hazard ratio between age 5 and adulthood was 0.93 (95% CI, 0.58-1.49).

The findings confirmed what they had suspected. Dr. Fink summarized simply, “If you always slept under a net, you did much better than if you never slept under the net. If you slept [under a net] more than half of the time, it was much better than if you slept [under a net] less than half the time.” So the more time children slept under bed nets, the less likely they were to acquire malaria. Dr. Fink stressed that the findings showing protective efficacy persisted into adulthood. “It seems just having a healthier early life actually makes you more resilient against other future infections.”

One of the theoretical concerns was that using nets would delay developing functional immunity and that there might be an increase in mortality seen later. This study showed that did not happen.

An accompanying commentary noted that there was some potential that families receiving nets were better off than those that didn’t but concluded that such confounding had been accounted for in other analyses.

Mark Wilson, ScD, professor emeritus of epidemiology, University of Michigan, Ann Arbor, concurred. He told this news organization that the study was “very well designed,” and the researchers “did a fantastic job” in tracking patients 20 years later.

“This is astounding!” he added. “It’s very rare to find this amount of follow-up.”

Dr. Fink’s conclusion? “Bed nets protect you in the short run, and being protected in the short run is also beneficial in the long run. There is no evidence that protecting kids in early childhood is weakening them in any way. So we should keep doing this.”

Dr. Fink and Dr. Wilson report no relevant financial relationships.

A version of this article first appeared on Medscape.com.

The U.S. Food and Drug Administration has approved rilpivirine and cabotegravir (Cabenuva) to 2-month dosing for adults living with HIV-1 infection.

Cabenuva was first approved by the FDA in January 2021 to be administered once monthly to treat HIV-1 infection in virologically suppressed adults. The medication was the first injectable complete antiretroviral regimen approved by the FDA.

Cabenuva can replace a current treatment in virologically suppressed adults on a stable antiretroviral regimen with no history of treatment failure and no known or suspected resistance to rilpivirine and cabotegravir, the Janssen Pharmaceutical Companies of Johnson & Johnson said in a press release. Janssen and ViiV Healthcare codeveloped the injectable antiretroviral medication Cabenuva.

The expanded label approval “marks an important step forward in advancing the treatment landscape for people living with HIV,” said Candice Long, the president of infectious diseases and vaccines at Janssen Therapeutics, in a Feb. 1 press release. “With this milestone, adults living with HIV have a treatment option that further reduces the frequency of medication.”

This expanded approval was based on global clinical trial of 1,045 adults with HIV-1, which found Cabenuva administered every 8 weeks (3 mL dose of both cabotegravir and rilpivirine) to be noninferior to the 4-week regimen (2 mL dose of both medicines). At week 48 of the trial, the proportion of participants with viral loads above 50 copies per milliliter was 1.7% in the 2-month arm and 1.0% in the 1-month arm. The study found that rates of virological suppression were similar for both the 1-month and 2-month regimens (93.5% and 94.3%, respectively).

The most common side effects were injection site reactions, pyrexia, fatigue, headache, musculoskeletal pain, nausea, sleep disorders, dizziness, and rash. Adverse reactions reported in individuals receiving the regimen every 2 months or once monthly were similar. Cabenuva is contraindicated for patients with a hypersensitivity reaction to cabotegravir or rilpivirine or for those receiving carbamazepine, oxcarbazepine, phenobarbital, phenytoin, rifabutin, rifampin, rifapentine, St. John’s wort, and more than one dose of systemic dexamethasone.

A version of this article first appeared on Medscape.com.

The U.S. Food and Drug Administration has approved rilpivirine and cabotegravir (Cabenuva) to 2-month dosing for adults living with HIV-1 infection.

Cabenuva was first approved by the FDA in January 2021 to be administered once monthly to treat HIV-1 infection in virologically suppressed adults. The medication was the first injectable complete antiretroviral regimen approved by the FDA.

Cabenuva can replace a current treatment in virologically suppressed adults on a stable antiretroviral regimen with no history of treatment failure and no known or suspected resistance to rilpivirine and cabotegravir, the Janssen Pharmaceutical Companies of Johnson & Johnson said in a press release. Janssen and ViiV Healthcare codeveloped the injectable antiretroviral medication Cabenuva.

The expanded label approval “marks an important step forward in advancing the treatment landscape for people living with HIV,” said Candice Long, the president of infectious diseases and vaccines at Janssen Therapeutics, in a Feb. 1 press release. “With this milestone, adults living with HIV have a treatment option that further reduces the frequency of medication.”

This expanded approval was based on global clinical trial of 1,045 adults with HIV-1, which found Cabenuva administered every 8 weeks (3 mL dose of both cabotegravir and rilpivirine) to be noninferior to the 4-week regimen (2 mL dose of both medicines). At week 48 of the trial, the proportion of participants with viral loads above 50 copies per milliliter was 1.7% in the 2-month arm and 1.0% in the 1-month arm. The study found that rates of virological suppression were similar for both the 1-month and 2-month regimens (93.5% and 94.3%, respectively).

The most common side effects were injection site reactions, pyrexia, fatigue, headache, musculoskeletal pain, nausea, sleep disorders, dizziness, and rash. Adverse reactions reported in individuals receiving the regimen every 2 months or once monthly were similar. Cabenuva is contraindicated for patients with a hypersensitivity reaction to cabotegravir or rilpivirine or for those receiving carbamazepine, oxcarbazepine, phenobarbital, phenytoin, rifabutin, rifampin, rifapentine, St. John’s wort, and more than one dose of systemic dexamethasone.

A version of this article first appeared on Medscape.com.

The U.S. Food and Drug Administration has approved rilpivirine and cabotegravir (Cabenuva) to 2-month dosing for adults living with HIV-1 infection.

Cabenuva was first approved by the FDA in January 2021 to be administered once monthly to treat HIV-1 infection in virologically suppressed adults. The medication was the first injectable complete antiretroviral regimen approved by the FDA.

Cabenuva can replace a current treatment in virologically suppressed adults on a stable antiretroviral regimen with no history of treatment failure and no known or suspected resistance to rilpivirine and cabotegravir, the Janssen Pharmaceutical Companies of Johnson & Johnson said in a press release. Janssen and ViiV Healthcare codeveloped the injectable antiretroviral medication Cabenuva.

The expanded label approval “marks an important step forward in advancing the treatment landscape for people living with HIV,” said Candice Long, the president of infectious diseases and vaccines at Janssen Therapeutics, in a Feb. 1 press release. “With this milestone, adults living with HIV have a treatment option that further reduces the frequency of medication.”

This expanded approval was based on global clinical trial of 1,045 adults with HIV-1, which found Cabenuva administered every 8 weeks (3 mL dose of both cabotegravir and rilpivirine) to be noninferior to the 4-week regimen (2 mL dose of both medicines). At week 48 of the trial, the proportion of participants with viral loads above 50 copies per milliliter was 1.7% in the 2-month arm and 1.0% in the 1-month arm. The study found that rates of virological suppression were similar for both the 1-month and 2-month regimens (93.5% and 94.3%, respectively).

The most common side effects were injection site reactions, pyrexia, fatigue, headache, musculoskeletal pain, nausea, sleep disorders, dizziness, and rash. Adverse reactions reported in individuals receiving the regimen every 2 months or once monthly were similar. Cabenuva is contraindicated for patients with a hypersensitivity reaction to cabotegravir or rilpivirine or for those receiving carbamazepine, oxcarbazepine, phenobarbital, phenytoin, rifabutin, rifampin, rifapentine, St. John’s wort, and more than one dose of systemic dexamethasone.

A version of this article first appeared on Medscape.com.

It is a great mystery of infectious disease: Why are some people seemingly unaffected by illness that harms others? During the COVID-19 pandemic, we’ve seen this play out time and time again when whole families get sick except for one or two fortunate family members. And at so-called superspreader events that infect many, a lucky few typically walk away with their health intact. Did the virus never enter their bodies? Or do some people have natural resistance to pathogens they’ve never been exposed to before encoded in their genes?

Resistance to infectious disease is much more than a scientific curiosity and studying how it works can be a path to curb future outbreaks.

“In the event that we could identify what makes some people resistant, that immediately opens avenues for therapeutics that we could apply in all those other people who do suffer from the disease,” says András Spaan, MD, a microbiologist at Rockefeller University in New York.

Dr. Spaan is part of an international effort to identify genetic variations that spare people from becoming infected with SARS-CoV-2, the virus that causes COVID-19.

There’s far more research on what drives the tendency to get infectious diseases than on resistance to them. But a few researchers are investigating resistance to some of the world’s most common and deadly infectious diseases, and in a few cases, they’ve already translated these insights into treatments.

Perhaps the strongest example of how odd genes of just a few people can inspire treatments to help many comes from research on the human immunodeficiency virus (HIV), the virus that causes acquired immune deficiency syndrome (AIDS).
 

A genetic quirk

In the mid-1990s, several groups of researchers independently identified a mutation in a gene called CCR5 linked to resistance to HIV infection.

The gene encodes a protein on the surface of some white blood cells that helps set up the movement of other immune cells to fight infections. HIV, meanwhile, uses the CCR5 protein to help it enter the white blood cells that it infects.

The mutation, known as delta 32, results in a shorter than usual protein that doesn’t reach the surface of the cell. People who carry two copies of the delta 32 form of CCR5 do not have any CCR5 protein on the outside of their white blood cells.

Researchers, led by molecular immunologist Philip Murphy, MD, at the National Institute of Allergy and Infectious Diseases in Bethesda, Md, showed in 1997 that people with two copies of the mutation were unusually common among a group of men who were at especially high risk of HIV exposure, but had never contracted the virus. And out of more than 700 HIV-positive people, none carried two copies of CCR5 delta 32.

Pharmaceutical companies used these insights to develop drugs to block CCR5 and delay the development of AIDS. For instance, the drug maraviroc, marketed by Pfizer, was approved for use in HIV-positive people in 2007.

Only a few examples of this kind of inborn, genetically determined complete resistance to infection have ever been heard of. All of them involve cell-surface molecules that are believed to help a virus or other pathogen gain entry to the cell.
 

Locking out illness

“The first step for any intracellular pathogen is getting inside the cell. And if you’re missing the doorway, then the virus can’t accomplish the first step in its life cycle,” Dr. Murphy says. “Getting inside is fundamental.”

Changes in cell-surface molecules can also make someone more likely to have an infection or severe disease. One such group of cell-surface molecules that have been linked to both increasing and decreasing the risk of various infections are histo-blood group antigens. The most familiar members of this group are the molecules that define blood types A, B, and O.

Scientists have also identified one example of total resistance to infection involving these molecules. In 2003, researchers showed that people who lack a functional copy of a gene known as FUT2 cannot be infected with Norwalk virus, one of more than 30 viruses in the norovirus family that cause illness in the digestive tract.

The gene FUT2 encodes an enzyme that determines whether or not blood group antigens are found in a person’s saliva and other body fluids as well as on their red blood cells.

“It didn’t matter how many virus particles we challenged an individual with, if they did not have that first enzyme, they did not get infected,” says researcher Lisa Lindesmith, a virologist at the University of North Carolina in Chapel Hill.
 

No norovirus

Norwalk is a relatively rare type of norovirus. But FUT2 deficiency also provides some protection against the most common strains of norovirus, known as GII.4, which have periodically swept across the world over the past quarter-century. These illnesses take an especially heavy toll on children in the developing world, causing malnutrition and contributing to infant and child deaths.

But progress in translating these insights about genetic resistance into drugs or other things that could reduce the burden of noroviruses has been slow.

“The biggest barrier here is lack of ability to study the virus outside of humans,” Lindesmith says.

Noroviruses are very difficult to grow in the lab, “and there’s no small animal model of gastrointestinal illness caused by the viruses.”

We are clearly making giant strides in improving those skills,” says Lindesmith. “But we are just not quite there yet.”

In the years before COVID-19 emerged, tuberculosis was responsible for the largest number of annual worldwide deaths from an infectious disease. It’s a lung disease caused by the bacterium Mycobacterium tuberculosis, and it has been a pandemic for thousands of years.

Some 85%-95% of people with intact immune systems who are infected with TB control the infection and never get active lung disease. And some people who have intense, continuing exposure to the bacterium, which is spread through droplets and aerosols from people with active lung disease, apparently never become infected at all.
 

Thwarting uberculosis

Understanding the ways of these different forms of resistance could help in the search for vaccines, treatments, and other ways to fight tuberculosis, says Elouise Kroon, MD, a graduate student at Stellenbosch University in Cape Town, South Africa.

“What makes it particularly hard to study is the fact that there is no gold standard to measure infection,” she says. “So, what we do is infer infection from two different types of tests” -- a skin test and a blood test that measure different kinds of immune response to molecules from the bacterium.

Dr. Kroon and other researchers have studied resistance to infection by following people living in the same household as those with active lung disease or people who live and work in crowded conditions in high-risk communities. But not all such studies have used the same definition of so-called resisters, documented exposure in the same way, or followed up to ensure that people continue to test negative over the long term.

The best clue that has emerged from studies so far links resistance to infection to certain variations in immune molecules known as HLA class II antigens, says Marlo Möller, PhD, a professor in the TB Host Genetics Research Group at Stellenbosch University.

“That always seems to pop up everywhere. But the rest is not so obvious,” she says. “A lot of the studies don’t find the same thing. It’s different in different populations,” which may be a result of the long evolutionary history between tuberculosis and humans, as well as the fact that different strains of the bacterium are prevalent in different parts of the world.

COVID-19 is a much newer infectious disease, but teasing out how it contributes to both severe illness and resistance to infection is still a major task.
 

Overcoming COVID

Early in the pandemic, research by the COVID Human Genetic Effort, the international consortium that Dr. Spaan is part of, linked severe COVID-19 pneumonia to the lack of immune molecules known as type I interferons and to antibodies produced by the body that destroy these molecules. Together, these mechanisms explain about one-fifth of severe COVID-19 cases, the researchers reported in 2021.

A few studies by other groups have explored resistance to COVID-19 infection, suggesting that reduced risk of contracting the virus is tied to certain blood group factors. People with Type O blood appear to be at slightly reduced risk of infection, for example.

But the studies done so far are designed to find common genetic variations, which generally have a small effect on resistance. Now, genetic researchers are launching an effort to identify genetic resistance factors with a big effect, even if they are vanishingly rare.

The group is recruiting people who did not become infected with COVID-19 despite heavy exposure, such as those living in households where all the other members got sick or people who were exposed to a superspreader event but did not become ill. As with tuberculosis, being certain that someone has not been infected with the virus can be tricky, but the team is using several blood tests to home in on the people most likely to have escaped infection.

They plan to sequence the genomes of these people to identify things that strongly affect infection risk, then do more laboratory studies to try to tease out the means of resistance.

Their work is inspired by earlier efforts to uncover inborn resistance to infections, Dr. Spaan says. Despite the lack of known examples of such resistance, he is optimistic about the possibilities. Those earlier efforts took place in “a different epoch,” before there were rapid sequencing technologies, Dr. Spaan says.

“Now we have modern technologies to do this more systematically.”

The emergence of viral variants such as the Delta and Omicron COVID strains raises the stakes of the work, he continues.

“The need to unravel these inborn mechanisms of resistance to COVID has become even more important because of these new variants and the anticipation that we will have COVID with us for years.”

A version of this article first appeared on WebMD.com.

It is a great mystery of infectious disease: Why are some people seemingly unaffected by illness that harms others? During the COVID-19 pandemic, we’ve seen this play out time and time again when whole families get sick except for one or two fortunate family members. And at so-called superspreader events that infect many, a lucky few typically walk away with their health intact. Did the virus never enter their bodies? Or do some people have natural resistance to pathogens they’ve never been exposed to before encoded in their genes?

Resistance to infectious disease is much more than a scientific curiosity and studying how it works can be a path to curb future outbreaks.

“In the event that we could identify what makes some people resistant, that immediately opens avenues for therapeutics that we could apply in all those other people who do suffer from the disease,” says András Spaan, MD, a microbiologist at Rockefeller University in New York.

Dr. Spaan is part of an international effort to identify genetic variations that spare people from becoming infected with SARS-CoV-2, the virus that causes COVID-19.

There’s far more research on what drives the tendency to get infectious diseases than on resistance to them. But a few researchers are investigating resistance to some of the world’s most common and deadly infectious diseases, and in a few cases, they’ve already translated these insights into treatments.

Perhaps the strongest example of how odd genes of just a few people can inspire treatments to help many comes from research on the human immunodeficiency virus (HIV), the virus that causes acquired immune deficiency syndrome (AIDS).
 

A genetic quirk

In the mid-1990s, several groups of researchers independently identified a mutation in a gene called CCR5 linked to resistance to HIV infection.

The gene encodes a protein on the surface of some white blood cells that helps set up the movement of other immune cells to fight infections. HIV, meanwhile, uses the CCR5 protein to help it enter the white blood cells that it infects.

The mutation, known as delta 32, results in a shorter than usual protein that doesn’t reach the surface of the cell. People who carry two copies of the delta 32 form of CCR5 do not have any CCR5 protein on the outside of their white blood cells.

Researchers, led by molecular immunologist Philip Murphy, MD, at the National Institute of Allergy and Infectious Diseases in Bethesda, Md, showed in 1997 that people with two copies of the mutation were unusually common among a group of men who were at especially high risk of HIV exposure, but had never contracted the virus. And out of more than 700 HIV-positive people, none carried two copies of CCR5 delta 32.

Pharmaceutical companies used these insights to develop drugs to block CCR5 and delay the development of AIDS. For instance, the drug maraviroc, marketed by Pfizer, was approved for use in HIV-positive people in 2007.

Only a few examples of this kind of inborn, genetically determined complete resistance to infection have ever been heard of. All of them involve cell-surface molecules that are believed to help a virus or other pathogen gain entry to the cell.
 

Locking out illness

“The first step for any intracellular pathogen is getting inside the cell. And if you’re missing the doorway, then the virus can’t accomplish the first step in its life cycle,” Dr. Murphy says. “Getting inside is fundamental.”

Changes in cell-surface molecules can also make someone more likely to have an infection or severe disease. One such group of cell-surface molecules that have been linked to both increasing and decreasing the risk of various infections are histo-blood group antigens. The most familiar members of this group are the molecules that define blood types A, B, and O.

Scientists have also identified one example of total resistance to infection involving these molecules. In 2003, researchers showed that people who lack a functional copy of a gene known as FUT2 cannot be infected with Norwalk virus, one of more than 30 viruses in the norovirus family that cause illness in the digestive tract.

The gene FUT2 encodes an enzyme that determines whether or not blood group antigens are found in a person’s saliva and other body fluids as well as on their red blood cells.

“It didn’t matter how many virus particles we challenged an individual with, if they did not have that first enzyme, they did not get infected,” says researcher Lisa Lindesmith, a virologist at the University of North Carolina in Chapel Hill.
 

No norovirus

Norwalk is a relatively rare type of norovirus. But FUT2 deficiency also provides some protection against the most common strains of norovirus, known as GII.4, which have periodically swept across the world over the past quarter-century. These illnesses take an especially heavy toll on children in the developing world, causing malnutrition and contributing to infant and child deaths.

But progress in translating these insights about genetic resistance into drugs or other things that could reduce the burden of noroviruses has been slow.

“The biggest barrier here is lack of ability to study the virus outside of humans,” Lindesmith says.

Noroviruses are very difficult to grow in the lab, “and there’s no small animal model of gastrointestinal illness caused by the viruses.”

We are clearly making giant strides in improving those skills,” says Lindesmith. “But we are just not quite there yet.”

In the years before COVID-19 emerged, tuberculosis was responsible for the largest number of annual worldwide deaths from an infectious disease. It’s a lung disease caused by the bacterium Mycobacterium tuberculosis, and it has been a pandemic for thousands of years.

Some 85%-95% of people with intact immune systems who are infected with TB control the infection and never get active lung disease. And some people who have intense, continuing exposure to the bacterium, which is spread through droplets and aerosols from people with active lung disease, apparently never become infected at all.
 

Thwarting uberculosis

Understanding the ways of these different forms of resistance could help in the search for vaccines, treatments, and other ways to fight tuberculosis, says Elouise Kroon, MD, a graduate student at Stellenbosch University in Cape Town, South Africa.

“What makes it particularly hard to study is the fact that there is no gold standard to measure infection,” she says. “So, what we do is infer infection from two different types of tests” -- a skin test and a blood test that measure different kinds of immune response to molecules from the bacterium.

Dr. Kroon and other researchers have studied resistance to infection by following people living in the same household as those with active lung disease or people who live and work in crowded conditions in high-risk communities. But not all such studies have used the same definition of so-called resisters, documented exposure in the same way, or followed up to ensure that people continue to test negative over the long term.

The best clue that has emerged from studies so far links resistance to infection to certain variations in immune molecules known as HLA class II antigens, says Marlo Möller, PhD, a professor in the TB Host Genetics Research Group at Stellenbosch University.

“That always seems to pop up everywhere. But the rest is not so obvious,” she says. “A lot of the studies don’t find the same thing. It’s different in different populations,” which may be a result of the long evolutionary history between tuberculosis and humans, as well as the fact that different strains of the bacterium are prevalent in different parts of the world.

COVID-19 is a much newer infectious disease, but teasing out how it contributes to both severe illness and resistance to infection is still a major task.
 

Overcoming COVID

Early in the pandemic, research by the COVID Human Genetic Effort, the international consortium that Dr. Spaan is part of, linked severe COVID-19 pneumonia to the lack of immune molecules known as type I interferons and to antibodies produced by the body that destroy these molecules. Together, these mechanisms explain about one-fifth of severe COVID-19 cases, the researchers reported in 2021.

A few studies by other groups have explored resistance to COVID-19 infection, suggesting that reduced risk of contracting the virus is tied to certain blood group factors. People with Type O blood appear to be at slightly reduced risk of infection, for example.

But the studies done so far are designed to find common genetic variations, which generally have a small effect on resistance. Now, genetic researchers are launching an effort to identify genetic resistance factors with a big effect, even if they are vanishingly rare.

The group is recruiting people who did not become infected with COVID-19 despite heavy exposure, such as those living in households where all the other members got sick or people who were exposed to a superspreader event but did not become ill. As with tuberculosis, being certain that someone has not been infected with the virus can be tricky, but the team is using several blood tests to home in on the people most likely to have escaped infection.

They plan to sequence the genomes of these people to identify things that strongly affect infection risk, then do more laboratory studies to try to tease out the means of resistance.

Their work is inspired by earlier efforts to uncover inborn resistance to infections, Dr. Spaan says. Despite the lack of known examples of such resistance, he is optimistic about the possibilities. Those earlier efforts took place in “a different epoch,” before there were rapid sequencing technologies, Dr. Spaan says.

“Now we have modern technologies to do this more systematically.”

The emergence of viral variants such as the Delta and Omicron COVID strains raises the stakes of the work, he continues.

“The need to unravel these inborn mechanisms of resistance to COVID has become even more important because of these new variants and the anticipation that we will have COVID with us for years.”

A version of this article first appeared on WebMD.com.

It is a great mystery of infectious disease: Why are some people seemingly unaffected by illness that harms others? During the COVID-19 pandemic, we’ve seen this play out time and time again when whole families get sick except for one or two fortunate family members. And at so-called superspreader events that infect many, a lucky few typically walk away with their health intact. Did the virus never enter their bodies? Or do some people have natural resistance to pathogens they’ve never been exposed to before encoded in their genes?

Resistance to infectious disease is much more than a scientific curiosity and studying how it works can be a path to curb future outbreaks.

“In the event that we could identify what makes some people resistant, that immediately opens avenues for therapeutics that we could apply in all those other people who do suffer from the disease,” says András Spaan, MD, a microbiologist at Rockefeller University in New York.

Dr. Spaan is part of an international effort to identify genetic variations that spare people from becoming infected with SARS-CoV-2, the virus that causes COVID-19.

There’s far more research on what drives the tendency to get infectious diseases than on resistance to them. But a few researchers are investigating resistance to some of the world’s most common and deadly infectious diseases, and in a few cases, they’ve already translated these insights into treatments.

Perhaps the strongest example of how odd genes of just a few people can inspire treatments to help many comes from research on the human immunodeficiency virus (HIV), the virus that causes acquired immune deficiency syndrome (AIDS).
 

A genetic quirk

In the mid-1990s, several groups of researchers independently identified a mutation in a gene called CCR5 linked to resistance to HIV infection.

The gene encodes a protein on the surface of some white blood cells that helps set up the movement of other immune cells to fight infections. HIV, meanwhile, uses the CCR5 protein to help it enter the white blood cells that it infects.

The mutation, known as delta 32, results in a shorter than usual protein that doesn’t reach the surface of the cell. People who carry two copies of the delta 32 form of CCR5 do not have any CCR5 protein on the outside of their white blood cells.

Researchers, led by molecular immunologist Philip Murphy, MD, at the National Institute of Allergy and Infectious Diseases in Bethesda, Md, showed in 1997 that people with two copies of the mutation were unusually common among a group of men who were at especially high risk of HIV exposure, but had never contracted the virus. And out of more than 700 HIV-positive people, none carried two copies of CCR5 delta 32.

Pharmaceutical companies used these insights to develop drugs to block CCR5 and delay the development of AIDS. For instance, the drug maraviroc, marketed by Pfizer, was approved for use in HIV-positive people in 2007.

Only a few examples of this kind of inborn, genetically determined complete resistance to infection have ever been heard of. All of them involve cell-surface molecules that are believed to help a virus or other pathogen gain entry to the cell.
 

Locking out illness

“The first step for any intracellular pathogen is getting inside the cell. And if you’re missing the doorway, then the virus can’t accomplish the first step in its life cycle,” Dr. Murphy says. “Getting inside is fundamental.”

Changes in cell-surface molecules can also make someone more likely to have an infection or severe disease. One such group of cell-surface molecules that have been linked to both increasing and decreasing the risk of various infections are histo-blood group antigens. The most familiar members of this group are the molecules that define blood types A, B, and O.

Scientists have also identified one example of total resistance to infection involving these molecules. In 2003, researchers showed that people who lack a functional copy of a gene known as FUT2 cannot be infected with Norwalk virus, one of more than 30 viruses in the norovirus family that cause illness in the digestive tract.

The gene FUT2 encodes an enzyme that determines whether or not blood group antigens are found in a person’s saliva and other body fluids as well as on their red blood cells.

“It didn’t matter how many virus particles we challenged an individual with, if they did not have that first enzyme, they did not get infected,” says researcher Lisa Lindesmith, a virologist at the University of North Carolina in Chapel Hill.
 

No norovirus

Norwalk is a relatively rare type of norovirus. But FUT2 deficiency also provides some protection against the most common strains of norovirus, known as GII.4, which have periodically swept across the world over the past quarter-century. These illnesses take an especially heavy toll on children in the developing world, causing malnutrition and contributing to infant and child deaths.

But progress in translating these insights about genetic resistance into drugs or other things that could reduce the burden of noroviruses has been slow.

“The biggest barrier here is lack of ability to study the virus outside of humans,” Lindesmith says.

Noroviruses are very difficult to grow in the lab, “and there’s no small animal model of gastrointestinal illness caused by the viruses.”

We are clearly making giant strides in improving those skills,” says Lindesmith. “But we are just not quite there yet.”

In the years before COVID-19 emerged, tuberculosis was responsible for the largest number of annual worldwide deaths from an infectious disease. It’s a lung disease caused by the bacterium Mycobacterium tuberculosis, and it has been a pandemic for thousands of years.

Some 85%-95% of people with intact immune systems who are infected with TB control the infection and never get active lung disease. And some people who have intense, continuing exposure to the bacterium, which is spread through droplets and aerosols from people with active lung disease, apparently never become infected at all.
 

Thwarting uberculosis

Understanding the ways of these different forms of resistance could help in the search for vaccines, treatments, and other ways to fight tuberculosis, says Elouise Kroon, MD, a graduate student at Stellenbosch University in Cape Town, South Africa.

“What makes it particularly hard to study is the fact that there is no gold standard to measure infection,” she says. “So, what we do is infer infection from two different types of tests” -- a skin test and a blood test that measure different kinds of immune response to molecules from the bacterium.

Dr. Kroon and other researchers have studied resistance to infection by following people living in the same household as those with active lung disease or people who live and work in crowded conditions in high-risk communities. But not all such studies have used the same definition of so-called resisters, documented exposure in the same way, or followed up to ensure that people continue to test negative over the long term.

The best clue that has emerged from studies so far links resistance to infection to certain variations in immune molecules known as HLA class II antigens, says Marlo Möller, PhD, a professor in the TB Host Genetics Research Group at Stellenbosch University.

“That always seems to pop up everywhere. But the rest is not so obvious,” she says. “A lot of the studies don’t find the same thing. It’s different in different populations,” which may be a result of the long evolutionary history between tuberculosis and humans, as well as the fact that different strains of the bacterium are prevalent in different parts of the world.

COVID-19 is a much newer infectious disease, but teasing out how it contributes to both severe illness and resistance to infection is still a major task.
 

Overcoming COVID

Early in the pandemic, research by the COVID Human Genetic Effort, the international consortium that Dr. Spaan is part of, linked severe COVID-19 pneumonia to the lack of immune molecules known as type I interferons and to antibodies produced by the body that destroy these molecules. Together, these mechanisms explain about one-fifth of severe COVID-19 cases, the researchers reported in 2021.

A few studies by other groups have explored resistance to COVID-19 infection, suggesting that reduced risk of contracting the virus is tied to certain blood group factors. People with Type O blood appear to be at slightly reduced risk of infection, for example.

But the studies done so far are designed to find common genetic variations, which generally have a small effect on resistance. Now, genetic researchers are launching an effort to identify genetic resistance factors with a big effect, even if they are vanishingly rare.

The group is recruiting people who did not become infected with COVID-19 despite heavy exposure, such as those living in households where all the other members got sick or people who were exposed to a superspreader event but did not become ill. As with tuberculosis, being certain that someone has not been infected with the virus can be tricky, but the team is using several blood tests to home in on the people most likely to have escaped infection.

They plan to sequence the genomes of these people to identify things that strongly affect infection risk, then do more laboratory studies to try to tease out the means of resistance.

Their work is inspired by earlier efforts to uncover inborn resistance to infections, Dr. Spaan says. Despite the lack of known examples of such resistance, he is optimistic about the possibilities. Those earlier efforts took place in “a different epoch,” before there were rapid sequencing technologies, Dr. Spaan says.

“Now we have modern technologies to do this more systematically.”

The emergence of viral variants such as the Delta and Omicron COVID strains raises the stakes of the work, he continues.

“The need to unravel these inborn mechanisms of resistance to COVID has become even more important because of these new variants and the anticipation that we will have COVID with us for years.”

A version of this article first appeared on WebMD.com.

A subcutaneous antibody combination of casirivimab and imdevimab given to asymptomatic people who tested positive for SARS-CoV-2 significantly lowered the incidence of symptomatic COVID-19 over 28 days, new research shows.

Results of the study by Meagan P. O’Brien, MD, from Regeneron Pharmaceuticals and one of the study’s funders, and coauthors were published online Jan. 14, 2022, in an original investigation in JAMA.

The results suggest new potential for monoclonal antibodies currently used for postexposure prophylaxis and treatment of symptomatic SARS-CoV-2. It has not been clear whether monoclonal antibodies can benefit people with asymptomatic SARS-CoV-2 infection.

The trial included 314 participants (mean age, 41 years; 51.6% women). Of the participants, 310 (99.7%) completed the efficacy assessment period, and 204 were asymptomatic and tested negative at baseline and were included in the primary efficacy analysis.

The subcutaneous combination of casirivimab and imdevimab, 1,200 mg (600 mg each), significantly prevented progression to symptomatic disease (29/100 [29.0%] vs. 44/104 [42.3%] with placebo; odds ratio, 0.54 [95% confidence interval, 0.30-0.97]; P = .04; absolute risk difference, −13.3% [95% CI, −26.3% to −0.3%]).

These results were part of a randomized, double-blind, placebo-controlled, phase 3 trial of close household contacts of a SARS-CoV-2–infected person at 112 sites in the United States, Romania, and Moldova. They were enrolled between July 13, 2020, and Jan. 28, 2021; follow-up ended March 11, 2021.

Asymptomatic people at least 12 years old were eligible if identified within 96 hours of index case positive test collection and were randomly assigned 1:1 to receive one dose of subcutaneous casirivimab and imdevimab (n = 158), or placebo (n = 156).

COVID-19 vaccination was prohibited before enrollment but was allowed after completing the 28-day efficacy assessment period.
 

Caution warranted

In an accompanying editorial, however, Jonathan Z. Li, MD, Brigham and Women’s Hospital and Harvard Medical School, both in Boston, and Rajesh T. Gandhi, MD, Massachusetts General Hospital, Boston, and Harvard Medical School, urged caution in interpreting the results.

They wrote that, although monoclonal antibodies are generally used in individuals at high risk for severe COVID-19, this study population was less vulnerable, with an average age of 41, and 30% had no risk for the disease.

“Of the remainder, the most common risk factor was being overweight (which confers less risk than other factors),” the editorialists wrote.

They pointed out, as did the study authors, that enrollment came before the emergence of the Delta and Omicron variants, and that both casirivimab and imdevimab maintain their activity against Delta but not against Omicron.

“While prevention of symptomatic infection has benefits,” they wrote, “the primary goal of monoclonal antibody therapy is to prevent progression to severe disease; however, this trial was unable to assess this outcome because there were only three hospitalizations (all in the placebo group). Also, this study was conducted prior to widespread COVID-19 vaccination; whether monoclonal antibodies have the same benefit in people who have breakthrough infection after vaccination is not known.”

The editorialists highlighted the subcutaneous delivery in this study.

They wrote that Dr. O’Brien and coauthors provide evidence that subcutaneous administration is effective in infected individuals. “However, high serum monoclonal antibody levels are achieved more quickly after intravenous administration than following subcutaneous injection; it is unknown whether intravenous administration might have led to even greater efficacy for individuals with asymptomatic SARS-CoV-2 infection.”

The authors of the study also add that, despite efforts to recruit non-White participants, relatively few non-White people were enrolled. Additionally, few adolescents were enrolled.

The sample size was also relatively small, they acknowledge, because of a study design in which the infection status of asymptomatic participants was not confirmed at inclusion.

Several of the authors are employees/stockholders of Regeneron, and have a patent pending, which has been licensed and is receiving royalties. The study was supported by Regeneron and F. Hoffmann–La Roche. This trial was conducted jointly with the National Institute of Allergy and Infectious Diseases and the National Institutes of Health. The CoVPN (COVID-19 Prevention Network) is supported by cooperative agreement awards from the NIAID and NIH.

A version of this article first appeared on Medscape.com.

A subcutaneous antibody combination of casirivimab and imdevimab given to asymptomatic people who tested positive for SARS-CoV-2 significantly lowered the incidence of symptomatic COVID-19 over 28 days, new research shows.

Results of the study by Meagan P. O’Brien, MD, from Regeneron Pharmaceuticals and one of the study’s funders, and coauthors were published online Jan. 14, 2022, in an original investigation in JAMA.

The results suggest new potential for monoclonal antibodies currently used for postexposure prophylaxis and treatment of symptomatic SARS-CoV-2. It has not been clear whether monoclonal antibodies can benefit people with asymptomatic SARS-CoV-2 infection.

The trial included 314 participants (mean age, 41 years; 51.6% women). Of the participants, 310 (99.7%) completed the efficacy assessment period, and 204 were asymptomatic and tested negative at baseline and were included in the primary efficacy analysis.

The subcutaneous combination of casirivimab and imdevimab, 1,200 mg (600 mg each), significantly prevented progression to symptomatic disease (29/100 [29.0%] vs. 44/104 [42.3%] with placebo; odds ratio, 0.54 [95% confidence interval, 0.30-0.97]; P = .04; absolute risk difference, −13.3% [95% CI, −26.3% to −0.3%]).

These results were part of a randomized, double-blind, placebo-controlled, phase 3 trial of close household contacts of a SARS-CoV-2–infected person at 112 sites in the United States, Romania, and Moldova. They were enrolled between July 13, 2020, and Jan. 28, 2021; follow-up ended March 11, 2021.

Asymptomatic people at least 12 years old were eligible if identified within 96 hours of index case positive test collection and were randomly assigned 1:1 to receive one dose of subcutaneous casirivimab and imdevimab (n = 158), or placebo (n = 156).

COVID-19 vaccination was prohibited before enrollment but was allowed after completing the 28-day efficacy assessment period.
 

Caution warranted

In an accompanying editorial, however, Jonathan Z. Li, MD, Brigham and Women’s Hospital and Harvard Medical School, both in Boston, and Rajesh T. Gandhi, MD, Massachusetts General Hospital, Boston, and Harvard Medical School, urged caution in interpreting the results.

They wrote that, although monoclonal antibodies are generally used in individuals at high risk for severe COVID-19, this study population was less vulnerable, with an average age of 41, and 30% had no risk for the disease.

“Of the remainder, the most common risk factor was being overweight (which confers less risk than other factors),” the editorialists wrote.

They pointed out, as did the study authors, that enrollment came before the emergence of the Delta and Omicron variants, and that both casirivimab and imdevimab maintain their activity against Delta but not against Omicron.

“While prevention of symptomatic infection has benefits,” they wrote, “the primary goal of monoclonal antibody therapy is to prevent progression to severe disease; however, this trial was unable to assess this outcome because there were only three hospitalizations (all in the placebo group). Also, this study was conducted prior to widespread COVID-19 vaccination; whether monoclonal antibodies have the same benefit in people who have breakthrough infection after vaccination is not known.”

The editorialists highlighted the subcutaneous delivery in this study.

They wrote that Dr. O’Brien and coauthors provide evidence that subcutaneous administration is effective in infected individuals. “However, high serum monoclonal antibody levels are achieved more quickly after intravenous administration than following subcutaneous injection; it is unknown whether intravenous administration might have led to even greater efficacy for individuals with asymptomatic SARS-CoV-2 infection.”

The authors of the study also add that, despite efforts to recruit non-White participants, relatively few non-White people were enrolled. Additionally, few adolescents were enrolled.

The sample size was also relatively small, they acknowledge, because of a study design in which the infection status of asymptomatic participants was not confirmed at inclusion.

Several of the authors are employees/stockholders of Regeneron, and have a patent pending, which has been licensed and is receiving royalties. The study was supported by Regeneron and F. Hoffmann–La Roche. This trial was conducted jointly with the National Institute of Allergy and Infectious Diseases and the National Institutes of Health. The CoVPN (COVID-19 Prevention Network) is supported by cooperative agreement awards from the NIAID and NIH.

A version of this article first appeared on Medscape.com.

A subcutaneous antibody combination of casirivimab and imdevimab given to asymptomatic people who tested positive for SARS-CoV-2 significantly lowered the incidence of symptomatic COVID-19 over 28 days, new research shows.

Results of the study by Meagan P. O’Brien, MD, from Regeneron Pharmaceuticals and one of the study’s funders, and coauthors were published online Jan. 14, 2022, in an original investigation in JAMA.

The results suggest new potential for monoclonal antibodies currently used for postexposure prophylaxis and treatment of symptomatic SARS-CoV-2. It has not been clear whether monoclonal antibodies can benefit people with asymptomatic SARS-CoV-2 infection.

The trial included 314 participants (mean age, 41 years; 51.6% women). Of the participants, 310 (99.7%) completed the efficacy assessment period, and 204 were asymptomatic and tested negative at baseline and were included in the primary efficacy analysis.

The subcutaneous combination of casirivimab and imdevimab, 1,200 mg (600 mg each), significantly prevented progression to symptomatic disease (29/100 [29.0%] vs. 44/104 [42.3%] with placebo; odds ratio, 0.54 [95% confidence interval, 0.30-0.97]; P = .04; absolute risk difference, −13.3% [95% CI, −26.3% to −0.3%]).

These results were part of a randomized, double-blind, placebo-controlled, phase 3 trial of close household contacts of a SARS-CoV-2–infected person at 112 sites in the United States, Romania, and Moldova. They were enrolled between July 13, 2020, and Jan. 28, 2021; follow-up ended March 11, 2021.

Asymptomatic people at least 12 years old were eligible if identified within 96 hours of index case positive test collection and were randomly assigned 1:1 to receive one dose of subcutaneous casirivimab and imdevimab (n = 158), or placebo (n = 156).

COVID-19 vaccination was prohibited before enrollment but was allowed after completing the 28-day efficacy assessment period.
 

Caution warranted

In an accompanying editorial, however, Jonathan Z. Li, MD, Brigham and Women’s Hospital and Harvard Medical School, both in Boston, and Rajesh T. Gandhi, MD, Massachusetts General Hospital, Boston, and Harvard Medical School, urged caution in interpreting the results.

They wrote that, although monoclonal antibodies are generally used in individuals at high risk for severe COVID-19, this study population was less vulnerable, with an average age of 41, and 30% had no risk for the disease.

“Of the remainder, the most common risk factor was being overweight (which confers less risk than other factors),” the editorialists wrote.

They pointed out, as did the study authors, that enrollment came before the emergence of the Delta and Omicron variants, and that both casirivimab and imdevimab maintain their activity against Delta but not against Omicron.

“While prevention of symptomatic infection has benefits,” they wrote, “the primary goal of monoclonal antibody therapy is to prevent progression to severe disease; however, this trial was unable to assess this outcome because there were only three hospitalizations (all in the placebo group). Also, this study was conducted prior to widespread COVID-19 vaccination; whether monoclonal antibodies have the same benefit in people who have breakthrough infection after vaccination is not known.”

The editorialists highlighted the subcutaneous delivery in this study.

They wrote that Dr. O’Brien and coauthors provide evidence that subcutaneous administration is effective in infected individuals. “However, high serum monoclonal antibody levels are achieved more quickly after intravenous administration than following subcutaneous injection; it is unknown whether intravenous administration might have led to even greater efficacy for individuals with asymptomatic SARS-CoV-2 infection.”

The authors of the study also add that, despite efforts to recruit non-White participants, relatively few non-White people were enrolled. Additionally, few adolescents were enrolled.

The sample size was also relatively small, they acknowledge, because of a study design in which the infection status of asymptomatic participants was not confirmed at inclusion.

Several of the authors are employees/stockholders of Regeneron, and have a patent pending, which has been licensed and is receiving royalties. The study was supported by Regeneron and F. Hoffmann–La Roche. This trial was conducted jointly with the National Institute of Allergy and Infectious Diseases and the National Institutes of Health. The CoVPN (COVID-19 Prevention Network) is supported by cooperative agreement awards from the NIAID and NIH.

A version of this article first appeared on Medscape.com.