Vaccines

Seroprevalence surveys suggest that, from the beginning of the pandemic to 2022, more than a third of the global population had been infected with SARS-CoV-2. As large numbers of people continue to be infected, the efficacy and duration of natural immunity, in terms of protection against SARS-CoV-2 reinfections and severe disease, are of crucial significance. The virus’s epidemiologic trajectory will be influenced by the trends in vaccine-induced and hybrid immunity.

Omicron’s immune evasion

Cases of SARS-CoV-2 reinfection are increasing around the world. According to data from the U.K. Health Security Agency, 650,000 people in England have been infected twice, and most of them were reinfected in the past 2 months. Before mid-November 2021, reinfections accounted for about 1% of reported cases, but the rate has now increased to around 10%. The reinfection risk was 16 times higher between mid-December 2021 and early January 2022. Experts believe that this spike in reinfections is related to the spread of Omicron, which overtook Delta as the dominant variant. Nonetheless, other aspects should also be considered.

Omicron’s greater propensity to spread is not unrelated to its ability to evade the body’s immune defenses. This aspect was raised in a letter recently published in the New England Journal of Medicine. The authors reported that the effectiveness of previous infection in preventing reinfection against the Alpha, Beta, and Delta variants was around 90%, but it was only 56% against Omicron.
 

Natural immunity

Natural immunity showed roughly similar effectiveness regarding protection against reinfection across different SARS-CoV-2 variants, with the exception of the Omicron variant. The risk of hospitalization and death was also reduced in SARS-CoV-2 reinfections versus primary infections. Observational studies indicate that natural immunity may offer equal or greater protection against SARS-CoV-2 infections, compared with immunization with two doses of an mRNA vaccine, but the data are not fully consistent.

Natural immunity seems to be relatively long-lasting. Data from Denmark and Austria show no evidence that protection against reinfections wanes after 6 months. Some investigations indicate that protection against reinfection is lowest 4-5 months after initial infection and increases thereafter, a finding that might hypothetically be explained by persistent viral shedding; that is, misclassification of prolonged SARS-CoV-2 infections as reinfections. While no comparison was made against information pertaining to unvaccinated, not previously-infected individuals, preliminary data from Israel suggest that protection from reinfection can decrease from 6 to more than 12 months after the first SARS-CoV-2 infection. Taken together, epidemiologic studies indicate that protection against reinfections by natural immunity lasts over 1 year with only moderate, if any, decline over this period. Among older individuals, immunocompromised patients, and those with certain comorbidities or exposure risk (for example, health care workers), rates of reinfection may be higher. It is plausible that reinfection risk may be a function of exposure risk.

There is accumulating evidence that reinfections may be significantly less severe than primary infections with SARS-CoV-2. Reduced clinical severity of SARS-CoV-2 reinfections naturally also makes sense from a biologic point of view, inasmuch as a previously primed immune system should be better prepared for a rechallenge with this virus.
 

Vaccine-induced immunity

The short-term (<4 months) efficacy of mRNA vaccines against SARS-CoV-2 is high and varies from 94.1% (Moderna) to 95% (BioNTech/Pfizer). This has been confirmed by randomized controlled trials and was subsequently confirmed in effectiveness studies in real-world settings. Waning efficacy was observed with respect to protection against SARS-CoV-2 infections (for example, only approximately 20% after about half a year in Qatar), whereas protection against severe disease was either sustained or showed only a moderate decline.

In individuals who received two doses of the BioNTech/Pfizer vaccine at least 5 months earlier, an additional vaccine dose, a so-called booster, significantly lowered mortality and severe illness. These findings suggest that the booster restored and probably exceeded the initial short-term efficacy of the initial vaccination.

Data are still emerging regarding the efficacy of boosters against the Omicron variants. Preliminary data suggest a far lower ability to restore protection from infection and vaccination. However, fatalities and hospitalizations remain low.
 

Natural immunity vs. vaccine-induced immunity

Comparisons of natural immunity with vaccine-induced immunity are complicated by a series of biases and by combinations of biases – for example, the biases of comparisons between infected and uninfected, plus the biases of comparisons between vaccinated and nonvaccinated, with strong potential selection biases and confounding. Of particular note, the proportion of people previously infected and/or vaccinated may influence estimates of effectiveness. Regarding this point, one study compared unvaccinated patients with a prior SARS-CoV-2 infection and vaccinated individuals followed up from a week after the second vaccine dose onward versus a group of unvaccinated, not previously infected individuals. The findings showed that, compared with unvaccinated, not previously infected individuals, the natural immunity group and the vaccinated group had similar protection of 94.8% and 92.8% against infection, of 94.1% and 94.2% against hospitalization, and of 96.4% and 94.4% against severe illness, respectively.

Hybrid immunity

The combination of a previous SARS-CoV-2 infection and a respective vaccination is called hybrid immunity. This combination seems to confer the greatest protection against SARS-CoV-2 infections, but several knowledge gaps remain regarding this issue.

Data from Israel showed that, when the time since the last immunity-conferring event (either primary infection or vaccination) was the same, the rates of SARS-CoV-2 infections were similar in the following groups: individuals who had a previous infection and no vaccination, individuals who had an infection and were then vaccinated with a single dose after at least 3 months, and individuals who were vaccinated (two doses) and then infected. Severe disease was relatively rare overall.

Data on the efficacy of hybrid immunity point in the direction of hybrid immunity being superior, as compared with either vaccine-induced (without a booster) immunity or natural immunity alone. Timing and mode of vaccination of previously infected individuals to achieve optimal hybrid immunity are central questions that remain to be addressed in future studies.

Given that vaccination rates are continuously increasing and that, by the beginning of 2022, perhaps half or more of the global population had already been infected with SARS-CoV-2, with the vast majority of this group not being officially detected, it would appear logical that future infection waves, even with highly transmissible variants of SARS-CoV-2, may be limited with respect to their maximum potential health burden. The advent of Omicron suggests that massive surges can occur even in populations with extremely high rates of previous vaccination and variable rates of prior infections. However, even then, the accompanying burden of hospitalizations and deaths is far less than what was seen in 2020 and 2021. One may argue that the pandemic has already transitioned to the endemic phase and that Omicron is an endemic wave occurring in the setting of already widespread population immunity.

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

Seroprevalence surveys suggest that, from the beginning of the pandemic to 2022, more than a third of the global population had been infected with SARS-CoV-2. As large numbers of people continue to be infected, the efficacy and duration of natural immunity, in terms of protection against SARS-CoV-2 reinfections and severe disease, are of crucial significance. The virus’s epidemiologic trajectory will be influenced by the trends in vaccine-induced and hybrid immunity.

Omicron’s immune evasion

Cases of SARS-CoV-2 reinfection are increasing around the world. According to data from the U.K. Health Security Agency, 650,000 people in England have been infected twice, and most of them were reinfected in the past 2 months. Before mid-November 2021, reinfections accounted for about 1% of reported cases, but the rate has now increased to around 10%. The reinfection risk was 16 times higher between mid-December 2021 and early January 2022. Experts believe that this spike in reinfections is related to the spread of Omicron, which overtook Delta as the dominant variant. Nonetheless, other aspects should also be considered.

Omicron’s greater propensity to spread is not unrelated to its ability to evade the body’s immune defenses. This aspect was raised in a letter recently published in the New England Journal of Medicine. The authors reported that the effectiveness of previous infection in preventing reinfection against the Alpha, Beta, and Delta variants was around 90%, but it was only 56% against Omicron.
 

Natural immunity

Natural immunity showed roughly similar effectiveness regarding protection against reinfection across different SARS-CoV-2 variants, with the exception of the Omicron variant. The risk of hospitalization and death was also reduced in SARS-CoV-2 reinfections versus primary infections. Observational studies indicate that natural immunity may offer equal or greater protection against SARS-CoV-2 infections, compared with immunization with two doses of an mRNA vaccine, but the data are not fully consistent.

Natural immunity seems to be relatively long-lasting. Data from Denmark and Austria show no evidence that protection against reinfections wanes after 6 months. Some investigations indicate that protection against reinfection is lowest 4-5 months after initial infection and increases thereafter, a finding that might hypothetically be explained by persistent viral shedding; that is, misclassification of prolonged SARS-CoV-2 infections as reinfections. While no comparison was made against information pertaining to unvaccinated, not previously-infected individuals, preliminary data from Israel suggest that protection from reinfection can decrease from 6 to more than 12 months after the first SARS-CoV-2 infection. Taken together, epidemiologic studies indicate that protection against reinfections by natural immunity lasts over 1 year with only moderate, if any, decline over this period. Among older individuals, immunocompromised patients, and those with certain comorbidities or exposure risk (for example, health care workers), rates of reinfection may be higher. It is plausible that reinfection risk may be a function of exposure risk.

There is accumulating evidence that reinfections may be significantly less severe than primary infections with SARS-CoV-2. Reduced clinical severity of SARS-CoV-2 reinfections naturally also makes sense from a biologic point of view, inasmuch as a previously primed immune system should be better prepared for a rechallenge with this virus.
 

Vaccine-induced immunity

The short-term (<4 months) efficacy of mRNA vaccines against SARS-CoV-2 is high and varies from 94.1% (Moderna) to 95% (BioNTech/Pfizer). This has been confirmed by randomized controlled trials and was subsequently confirmed in effectiveness studies in real-world settings. Waning efficacy was observed with respect to protection against SARS-CoV-2 infections (for example, only approximately 20% after about half a year in Qatar), whereas protection against severe disease was either sustained or showed only a moderate decline.

In individuals who received two doses of the BioNTech/Pfizer vaccine at least 5 months earlier, an additional vaccine dose, a so-called booster, significantly lowered mortality and severe illness. These findings suggest that the booster restored and probably exceeded the initial short-term efficacy of the initial vaccination.

Data are still emerging regarding the efficacy of boosters against the Omicron variants. Preliminary data suggest a far lower ability to restore protection from infection and vaccination. However, fatalities and hospitalizations remain low.
 

Natural immunity vs. vaccine-induced immunity

Comparisons of natural immunity with vaccine-induced immunity are complicated by a series of biases and by combinations of biases – for example, the biases of comparisons between infected and uninfected, plus the biases of comparisons between vaccinated and nonvaccinated, with strong potential selection biases and confounding. Of particular note, the proportion of people previously infected and/or vaccinated may influence estimates of effectiveness. Regarding this point, one study compared unvaccinated patients with a prior SARS-CoV-2 infection and vaccinated individuals followed up from a week after the second vaccine dose onward versus a group of unvaccinated, not previously infected individuals. The findings showed that, compared with unvaccinated, not previously infected individuals, the natural immunity group and the vaccinated group had similar protection of 94.8% and 92.8% against infection, of 94.1% and 94.2% against hospitalization, and of 96.4% and 94.4% against severe illness, respectively.

Hybrid immunity

The combination of a previous SARS-CoV-2 infection and a respective vaccination is called hybrid immunity. This combination seems to confer the greatest protection against SARS-CoV-2 infections, but several knowledge gaps remain regarding this issue.

Data from Israel showed that, when the time since the last immunity-conferring event (either primary infection or vaccination) was the same, the rates of SARS-CoV-2 infections were similar in the following groups: individuals who had a previous infection and no vaccination, individuals who had an infection and were then vaccinated with a single dose after at least 3 months, and individuals who were vaccinated (two doses) and then infected. Severe disease was relatively rare overall.

Data on the efficacy of hybrid immunity point in the direction of hybrid immunity being superior, as compared with either vaccine-induced (without a booster) immunity or natural immunity alone. Timing and mode of vaccination of previously infected individuals to achieve optimal hybrid immunity are central questions that remain to be addressed in future studies.

Given that vaccination rates are continuously increasing and that, by the beginning of 2022, perhaps half or more of the global population had already been infected with SARS-CoV-2, with the vast majority of this group not being officially detected, it would appear logical that future infection waves, even with highly transmissible variants of SARS-CoV-2, may be limited with respect to their maximum potential health burden. The advent of Omicron suggests that massive surges can occur even in populations with extremely high rates of previous vaccination and variable rates of prior infections. However, even then, the accompanying burden of hospitalizations and deaths is far less than what was seen in 2020 and 2021. One may argue that the pandemic has already transitioned to the endemic phase and that Omicron is an endemic wave occurring in the setting of already widespread population immunity.

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

Seroprevalence surveys suggest that, from the beginning of the pandemic to 2022, more than a third of the global population had been infected with SARS-CoV-2. As large numbers of people continue to be infected, the efficacy and duration of natural immunity, in terms of protection against SARS-CoV-2 reinfections and severe disease, are of crucial significance. The virus’s epidemiologic trajectory will be influenced by the trends in vaccine-induced and hybrid immunity.

Omicron’s immune evasion

Cases of SARS-CoV-2 reinfection are increasing around the world. According to data from the U.K. Health Security Agency, 650,000 people in England have been infected twice, and most of them were reinfected in the past 2 months. Before mid-November 2021, reinfections accounted for about 1% of reported cases, but the rate has now increased to around 10%. The reinfection risk was 16 times higher between mid-December 2021 and early January 2022. Experts believe that this spike in reinfections is related to the spread of Omicron, which overtook Delta as the dominant variant. Nonetheless, other aspects should also be considered.

Omicron’s greater propensity to spread is not unrelated to its ability to evade the body’s immune defenses. This aspect was raised in a letter recently published in the New England Journal of Medicine. The authors reported that the effectiveness of previous infection in preventing reinfection against the Alpha, Beta, and Delta variants was around 90%, but it was only 56% against Omicron.
 

Natural immunity

Natural immunity showed roughly similar effectiveness regarding protection against reinfection across different SARS-CoV-2 variants, with the exception of the Omicron variant. The risk of hospitalization and death was also reduced in SARS-CoV-2 reinfections versus primary infections. Observational studies indicate that natural immunity may offer equal or greater protection against SARS-CoV-2 infections, compared with immunization with two doses of an mRNA vaccine, but the data are not fully consistent.

Natural immunity seems to be relatively long-lasting. Data from Denmark and Austria show no evidence that protection against reinfections wanes after 6 months. Some investigations indicate that protection against reinfection is lowest 4-5 months after initial infection and increases thereafter, a finding that might hypothetically be explained by persistent viral shedding; that is, misclassification of prolonged SARS-CoV-2 infections as reinfections. While no comparison was made against information pertaining to unvaccinated, not previously-infected individuals, preliminary data from Israel suggest that protection from reinfection can decrease from 6 to more than 12 months after the first SARS-CoV-2 infection. Taken together, epidemiologic studies indicate that protection against reinfections by natural immunity lasts over 1 year with only moderate, if any, decline over this period. Among older individuals, immunocompromised patients, and those with certain comorbidities or exposure risk (for example, health care workers), rates of reinfection may be higher. It is plausible that reinfection risk may be a function of exposure risk.

There is accumulating evidence that reinfections may be significantly less severe than primary infections with SARS-CoV-2. Reduced clinical severity of SARS-CoV-2 reinfections naturally also makes sense from a biologic point of view, inasmuch as a previously primed immune system should be better prepared for a rechallenge with this virus.
 

Vaccine-induced immunity

The short-term (<4 months) efficacy of mRNA vaccines against SARS-CoV-2 is high and varies from 94.1% (Moderna) to 95% (BioNTech/Pfizer). This has been confirmed by randomized controlled trials and was subsequently confirmed in effectiveness studies in real-world settings. Waning efficacy was observed with respect to protection against SARS-CoV-2 infections (for example, only approximately 20% after about half a year in Qatar), whereas protection against severe disease was either sustained or showed only a moderate decline.

In individuals who received two doses of the BioNTech/Pfizer vaccine at least 5 months earlier, an additional vaccine dose, a so-called booster, significantly lowered mortality and severe illness. These findings suggest that the booster restored and probably exceeded the initial short-term efficacy of the initial vaccination.

Data are still emerging regarding the efficacy of boosters against the Omicron variants. Preliminary data suggest a far lower ability to restore protection from infection and vaccination. However, fatalities and hospitalizations remain low.
 

Natural immunity vs. vaccine-induced immunity

Comparisons of natural immunity with vaccine-induced immunity are complicated by a series of biases and by combinations of biases – for example, the biases of comparisons between infected and uninfected, plus the biases of comparisons between vaccinated and nonvaccinated, with strong potential selection biases and confounding. Of particular note, the proportion of people previously infected and/or vaccinated may influence estimates of effectiveness. Regarding this point, one study compared unvaccinated patients with a prior SARS-CoV-2 infection and vaccinated individuals followed up from a week after the second vaccine dose onward versus a group of unvaccinated, not previously infected individuals. The findings showed that, compared with unvaccinated, not previously infected individuals, the natural immunity group and the vaccinated group had similar protection of 94.8% and 92.8% against infection, of 94.1% and 94.2% against hospitalization, and of 96.4% and 94.4% against severe illness, respectively.

Hybrid immunity

The combination of a previous SARS-CoV-2 infection and a respective vaccination is called hybrid immunity. This combination seems to confer the greatest protection against SARS-CoV-2 infections, but several knowledge gaps remain regarding this issue.

Data from Israel showed that, when the time since the last immunity-conferring event (either primary infection or vaccination) was the same, the rates of SARS-CoV-2 infections were similar in the following groups: individuals who had a previous infection and no vaccination, individuals who had an infection and were then vaccinated with a single dose after at least 3 months, and individuals who were vaccinated (two doses) and then infected. Severe disease was relatively rare overall.

Data on the efficacy of hybrid immunity point in the direction of hybrid immunity being superior, as compared with either vaccine-induced (without a booster) immunity or natural immunity alone. Timing and mode of vaccination of previously infected individuals to achieve optimal hybrid immunity are central questions that remain to be addressed in future studies.

Given that vaccination rates are continuously increasing and that, by the beginning of 2022, perhaps half or more of the global population had already been infected with SARS-CoV-2, with the vast majority of this group not being officially detected, it would appear logical that future infection waves, even with highly transmissible variants of SARS-CoV-2, may be limited with respect to their maximum potential health burden. The advent of Omicron suggests that massive surges can occur even in populations with extremely high rates of previous vaccination and variable rates of prior infections. However, even then, the accompanying burden of hospitalizations and deaths is far less than what was seen in 2020 and 2021. One may argue that the pandemic has already transitioned to the endemic phase and that Omicron is an endemic wave occurring in the setting of already widespread population immunity.

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

Moderna on March 23 released interim results indicating that its mRNA-1273 COVID vaccine produced “robust” neutralizing antibody titers in children aged 6 months to 6 years – levels similar to those seen in adults.

Vaccine efficacy against infection was 43.7% in children aged 6 months to 2 years and 37.5% among children aged 2-6 years, the new data from its phase 2/3 KidCOVE study show.

The company explained the lower efficacy numbers by noting that its study involving these younger children was conducted during the Omicron wave. The same decrease in efficacy against infection was reported in adults during the Omicron surge.

A majority of COVID-19 cases were mild in the approximately 6,900 children aged 6 months to 6 years in the study. No severe COVID-19 cases, hospitalizations, or deaths were reported.

The primary series of two 25-mcg doses of the vaccine given 28 days apart was generally well tolerated. Most adverse events were mild to moderate. For example, temperature greater than 38° C (>100.4° F) was reported for 17.0% of the 6-month-old to 2-year-old group and for 14.6% of the 2- to 6-year-old group. A few children, 0.2% of each group, experienced a temperature greater than 40° C (>104° F).

Moderna plans to include these response, efficacy, and safety data in an application to the Food and Drug Administration for emergency use authorization (EUA) of the vaccine in these younger children in the coming weeks.

“We now have clinical data on the performance of our vaccine from infants 6 months of age through older adults,” Moderna CEO Stephane Bancel said in a news release. He described the interim results as “good news for parents of children under 6 years of age.”
 

In other news

Moderna also announced that it began the FDA EUA submission process for a 50-μg two-dose primary series for children aged 6-12 years.

The company is also updating its EUA submission for a 100-mcg two-dose primary series for children and adolescents aged 12-18 years.

Similar to its booster research in adults, Moderna plans to evaluate the potential of a booster dose for all pediatric populations, including those aged 6 months to 6 years, 6-12 years, and adolescents. The company is evaluating both a booster dose of mRNA-1273 and its bivalent booster candidate (mRNA1273.214), which includes an Omicron variant booster and mRNA-1273.

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

Moderna on March 23 released interim results indicating that its mRNA-1273 COVID vaccine produced “robust” neutralizing antibody titers in children aged 6 months to 6 years – levels similar to those seen in adults.

Vaccine efficacy against infection was 43.7% in children aged 6 months to 2 years and 37.5% among children aged 2-6 years, the new data from its phase 2/3 KidCOVE study show.

The company explained the lower efficacy numbers by noting that its study involving these younger children was conducted during the Omicron wave. The same decrease in efficacy against infection was reported in adults during the Omicron surge.

A majority of COVID-19 cases were mild in the approximately 6,900 children aged 6 months to 6 years in the study. No severe COVID-19 cases, hospitalizations, or deaths were reported.

The primary series of two 25-mcg doses of the vaccine given 28 days apart was generally well tolerated. Most adverse events were mild to moderate. For example, temperature greater than 38° C (>100.4° F) was reported for 17.0% of the 6-month-old to 2-year-old group and for 14.6% of the 2- to 6-year-old group. A few children, 0.2% of each group, experienced a temperature greater than 40° C (>104° F).

Moderna plans to include these response, efficacy, and safety data in an application to the Food and Drug Administration for emergency use authorization (EUA) of the vaccine in these younger children in the coming weeks.

“We now have clinical data on the performance of our vaccine from infants 6 months of age through older adults,” Moderna CEO Stephane Bancel said in a news release. He described the interim results as “good news for parents of children under 6 years of age.”
 

In other news

Moderna also announced that it began the FDA EUA submission process for a 50-μg two-dose primary series for children aged 6-12 years.

The company is also updating its EUA submission for a 100-mcg two-dose primary series for children and adolescents aged 12-18 years.

Similar to its booster research in adults, Moderna plans to evaluate the potential of a booster dose for all pediatric populations, including those aged 6 months to 6 years, 6-12 years, and adolescents. The company is evaluating both a booster dose of mRNA-1273 and its bivalent booster candidate (mRNA1273.214), which includes an Omicron variant booster and mRNA-1273.

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

Moderna on March 23 released interim results indicating that its mRNA-1273 COVID vaccine produced “robust” neutralizing antibody titers in children aged 6 months to 6 years – levels similar to those seen in adults.

Vaccine efficacy against infection was 43.7% in children aged 6 months to 2 years and 37.5% among children aged 2-6 years, the new data from its phase 2/3 KidCOVE study show.

The company explained the lower efficacy numbers by noting that its study involving these younger children was conducted during the Omicron wave. The same decrease in efficacy against infection was reported in adults during the Omicron surge.

A majority of COVID-19 cases were mild in the approximately 6,900 children aged 6 months to 6 years in the study. No severe COVID-19 cases, hospitalizations, or deaths were reported.

The primary series of two 25-mcg doses of the vaccine given 28 days apart was generally well tolerated. Most adverse events were mild to moderate. For example, temperature greater than 38° C (>100.4° F) was reported for 17.0% of the 6-month-old to 2-year-old group and for 14.6% of the 2- to 6-year-old group. A few children, 0.2% of each group, experienced a temperature greater than 40° C (>104° F).

Moderna plans to include these response, efficacy, and safety data in an application to the Food and Drug Administration for emergency use authorization (EUA) of the vaccine in these younger children in the coming weeks.

“We now have clinical data on the performance of our vaccine from infants 6 months of age through older adults,” Moderna CEO Stephane Bancel said in a news release. He described the interim results as “good news for parents of children under 6 years of age.”
 

In other news

Moderna also announced that it began the FDA EUA submission process for a 50-μg two-dose primary series for children aged 6-12 years.

The company is also updating its EUA submission for a 100-mcg two-dose primary series for children and adolescents aged 12-18 years.

Similar to its booster research in adults, Moderna plans to evaluate the potential of a booster dose for all pediatric populations, including those aged 6 months to 6 years, 6-12 years, and adolescents. The company is evaluating both a booster dose of mRNA-1273 and its bivalent booster candidate (mRNA1273.214), which includes an Omicron variant booster and mRNA-1273.

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

In February, citing the need for more data, Pfizer and BioNTech announced that they were delaying the application for their COVID-19 vaccine for children under the age of 5. Earlier evidence suggests that two doses may not provide adequate protection in the 2- to 4-year old age group. With the larger number of infections and illness in the younger age group from the Omicron variant, Pfizer and BioNTech felt they needed more data on the effectiveness of a third dose.

This delay came as a disappointment to parents of children under 5 who have been eager to have them receive the vaccination. However, Peter Marks, MD, director of the Center for Biologics Evaluation and Research at the Food and Drug Administration, told parents that this delay should be reassuring – that the companies were doing important due diligence before releasing a product that is both safe and effective. The American Academy of Pediatrics wisely released a similar statement of reassurance and support.

It is difficult to know how many parents will eventually immunize their young children once the vaccine is approved. Any survey done more than a few weeks ago must be viewed cautiously as “the COVID numbers” around the country continue to improve and parental attitudes are likely to change.

There will always remain subgroups of parents on either extreme of the bell-shaped curve. Some will reject the under-5 vaccine simply because it is a vaccine. Some parents are so anxious to vaccinate that they will want to be first in line even if waiting is the more prudent approach. In a recent opinion piece appearing in the New York Times, a statistician writes that he is so eager to have his young children immunized that he is encouraging the FDA to replace its traditional reliance on “statistical significance” with a less rigid and binary method such as one based on Bayesian theory (Aubrey Carlton, “I’m a parent and a statistician. There’s a smarter way to think about the under-5 vaccine.” The New York Times. 2022 Mar 1.). However, what this statistician misses in his haste to vaccinate his own children is that we are dealing with an entire population with varying levels of scientific sophistication and appetite for risk. While “statistical significance” may no longer be cutting edge to some statisticians, most of the rest of the country finds the term reassuring.

It will be interesting to see what happens if and when the vaccine is approved. Will the American Academy of Pediatrics come out with a strong recommendation? I hope they are careful and provide a sufficient number of caveats, otherwise we in the trenches will again be left to provide more nuanced advice to families who are both anxious and hesitant.

Despite the recent surge in cases among young children, apparently as a result of the Omicron variant, the disease continues to cause less and milder disease among young children than it does in adults. And the degree to which illness in the pediatric population contributes to the health of the general population appears to still be a matter of debate. This may be yet another instance of when the crafty COVID-19 has moved with a pace that will make an under–age-5 vaccine of relatively little value.

First, we must be careful to assure ourselves that any side effects the vaccine might generate are well within an even more restricted acceptable range. Second, we must be careful not to squander our persuasive currency by promoting a vaccine that in retrospect may turn out to be of relatively little value.

Although there is ample evidence that education often fails to convince the committed anti-vaxxers, pediatricians continue to be held in high regard by most parents, many of whom are understandably confused by the tsunami of health information of mixed quality generated by the pandemic. We must be cautious not to cast ourselves as a group whose knee-jerk reaction is to recommend every vaccine with equal vigor. All vaccines are not created equal. We must be patient and prepared to adjust the level of our enthusiasm. We must continue to tailor our advice based on the hard data. Otherwise, parents will stop asking for our advice because they will believe that they already know what we’re going to say.

Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics, including “How to Say No to Your Toddler.” Other than a Littman stethoscope he accepted as a first-year medical student in 1966, Dr. Wilkoff reports having nothing to disclose. Email him at pdnews@mdedge.com.

In February, citing the need for more data, Pfizer and BioNTech announced that they were delaying the application for their COVID-19 vaccine for children under the age of 5. Earlier evidence suggests that two doses may not provide adequate protection in the 2- to 4-year old age group. With the larger number of infections and illness in the younger age group from the Omicron variant, Pfizer and BioNTech felt they needed more data on the effectiveness of a third dose.

This delay came as a disappointment to parents of children under 5 who have been eager to have them receive the vaccination. However, Peter Marks, MD, director of the Center for Biologics Evaluation and Research at the Food and Drug Administration, told parents that this delay should be reassuring – that the companies were doing important due diligence before releasing a product that is both safe and effective. The American Academy of Pediatrics wisely released a similar statement of reassurance and support.

It is difficult to know how many parents will eventually immunize their young children once the vaccine is approved. Any survey done more than a few weeks ago must be viewed cautiously as “the COVID numbers” around the country continue to improve and parental attitudes are likely to change.

There will always remain subgroups of parents on either extreme of the bell-shaped curve. Some will reject the under-5 vaccine simply because it is a vaccine. Some parents are so anxious to vaccinate that they will want to be first in line even if waiting is the more prudent approach. In a recent opinion piece appearing in the New York Times, a statistician writes that he is so eager to have his young children immunized that he is encouraging the FDA to replace its traditional reliance on “statistical significance” with a less rigid and binary method such as one based on Bayesian theory (Aubrey Carlton, “I’m a parent and a statistician. There’s a smarter way to think about the under-5 vaccine.” The New York Times. 2022 Mar 1.). However, what this statistician misses in his haste to vaccinate his own children is that we are dealing with an entire population with varying levels of scientific sophistication and appetite for risk. While “statistical significance” may no longer be cutting edge to some statisticians, most of the rest of the country finds the term reassuring.

It will be interesting to see what happens if and when the vaccine is approved. Will the American Academy of Pediatrics come out with a strong recommendation? I hope they are careful and provide a sufficient number of caveats, otherwise we in the trenches will again be left to provide more nuanced advice to families who are both anxious and hesitant.

Despite the recent surge in cases among young children, apparently as a result of the Omicron variant, the disease continues to cause less and milder disease among young children than it does in adults. And the degree to which illness in the pediatric population contributes to the health of the general population appears to still be a matter of debate. This may be yet another instance of when the crafty COVID-19 has moved with a pace that will make an under–age-5 vaccine of relatively little value.

First, we must be careful to assure ourselves that any side effects the vaccine might generate are well within an even more restricted acceptable range. Second, we must be careful not to squander our persuasive currency by promoting a vaccine that in retrospect may turn out to be of relatively little value.

Although there is ample evidence that education often fails to convince the committed anti-vaxxers, pediatricians continue to be held in high regard by most parents, many of whom are understandably confused by the tsunami of health information of mixed quality generated by the pandemic. We must be cautious not to cast ourselves as a group whose knee-jerk reaction is to recommend every vaccine with equal vigor. All vaccines are not created equal. We must be patient and prepared to adjust the level of our enthusiasm. We must continue to tailor our advice based on the hard data. Otherwise, parents will stop asking for our advice because they will believe that they already know what we’re going to say.

Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics, including “How to Say No to Your Toddler.” Other than a Littman stethoscope he accepted as a first-year medical student in 1966, Dr. Wilkoff reports having nothing to disclose. Email him at pdnews@mdedge.com.

In February, citing the need for more data, Pfizer and BioNTech announced that they were delaying the application for their COVID-19 vaccine for children under the age of 5. Earlier evidence suggests that two doses may not provide adequate protection in the 2- to 4-year old age group. With the larger number of infections and illness in the younger age group from the Omicron variant, Pfizer and BioNTech felt they needed more data on the effectiveness of a third dose.

This delay came as a disappointment to parents of children under 5 who have been eager to have them receive the vaccination. However, Peter Marks, MD, director of the Center for Biologics Evaluation and Research at the Food and Drug Administration, told parents that this delay should be reassuring – that the companies were doing important due diligence before releasing a product that is both safe and effective. The American Academy of Pediatrics wisely released a similar statement of reassurance and support.

It is difficult to know how many parents will eventually immunize their young children once the vaccine is approved. Any survey done more than a few weeks ago must be viewed cautiously as “the COVID numbers” around the country continue to improve and parental attitudes are likely to change.

There will always remain subgroups of parents on either extreme of the bell-shaped curve. Some will reject the under-5 vaccine simply because it is a vaccine. Some parents are so anxious to vaccinate that they will want to be first in line even if waiting is the more prudent approach. In a recent opinion piece appearing in the New York Times, a statistician writes that he is so eager to have his young children immunized that he is encouraging the FDA to replace its traditional reliance on “statistical significance” with a less rigid and binary method such as one based on Bayesian theory (Aubrey Carlton, “I’m a parent and a statistician. There’s a smarter way to think about the under-5 vaccine.” The New York Times. 2022 Mar 1.). However, what this statistician misses in his haste to vaccinate his own children is that we are dealing with an entire population with varying levels of scientific sophistication and appetite for risk. While “statistical significance” may no longer be cutting edge to some statisticians, most of the rest of the country finds the term reassuring.

It will be interesting to see what happens if and when the vaccine is approved. Will the American Academy of Pediatrics come out with a strong recommendation? I hope they are careful and provide a sufficient number of caveats, otherwise we in the trenches will again be left to provide more nuanced advice to families who are both anxious and hesitant.

Despite the recent surge in cases among young children, apparently as a result of the Omicron variant, the disease continues to cause less and milder disease among young children than it does in adults. And the degree to which illness in the pediatric population contributes to the health of the general population appears to still be a matter of debate. This may be yet another instance of when the crafty COVID-19 has moved with a pace that will make an under–age-5 vaccine of relatively little value.

First, we must be careful to assure ourselves that any side effects the vaccine might generate are well within an even more restricted acceptable range. Second, we must be careful not to squander our persuasive currency by promoting a vaccine that in retrospect may turn out to be of relatively little value.

Although there is ample evidence that education often fails to convince the committed anti-vaxxers, pediatricians continue to be held in high regard by most parents, many of whom are understandably confused by the tsunami of health information of mixed quality generated by the pandemic. We must be cautious not to cast ourselves as a group whose knee-jerk reaction is to recommend every vaccine with equal vigor. All vaccines are not created equal. We must be patient and prepared to adjust the level of our enthusiasm. We must continue to tailor our advice based on the hard data. Otherwise, parents will stop asking for our advice because they will believe that they already know what we’re going to say.

Dr. Wilkoff practiced primary care pediatrics in Brunswick, Maine, for nearly 40 years. He has authored several books on behavioral pediatrics, including “How to Say No to Your Toddler.” Other than a Littman stethoscope he accepted as a first-year medical student in 1966, Dr. Wilkoff reports having nothing to disclose. Email him at pdnews@mdedge.com.

Babies born to moms who were vaccinated against respiratory syncytial virus (RSV) while pregnant appear to need fewer antimicrobial prescriptions than babies of unvaccinated moms, according to authors of a recent study.

To fight antimicrobial resistance, we need to use fewer antimicrobial drugs, the authors write in Proceedings of the National Academy of Sciences.

“In this study, an RSV vaccine was administered to pregnant women to prevent infection in their infants by the transfer of protective antibody to the infant,” Kathryn M. Edwards, MD, a professor of pediatrics and the scientific director of the Vanderbilt vaccine research program at Vanderbilt University in Nashville, Tenn., told this news organization. Dr. Edwards was not involved in the study.

“The authors investigated the impact of the vaccine on the use of antibiotics in infants during the first 90 days of life,” Dr. Edwards added in an email. “They found that the use of antibiotics was less in infants born to mothers who received the RSV vaccine than in infants born to mothers who received placebo. … They suggest that reducing RSV infection in infants will reduce respiratory infections that trigger antibiotic use.”

Senior author Ramanan Laxminarayan, PhD, MPH, director and senior fellow at the Center for Disease Dynamics, Economics & Policy in Washington and his colleagues conducted a secondary analysis of a double-blind, randomized controlled trial at 87 sites in 11 countries on several continents.

In the original study, which was conducted between December 2015 and May 2018, 3,005 maternal participants and 2,978 infant participants received the experimental RSV F vaccine, and 1,573 maternal participants and 1,546 infants received a placebo shot. Baseline characteristics of mothers and infants were well balanced, according to the authors.

In the current study, infants born to mothers who received the RSV vaccine were found to be 12.9% (95% confidence interval, 1.3%-23.1%) less likely to be prescribed antimicrobials during their first 3 months of life, compared with infants whose mothers received placebo. Vaccine efficacy against antimicrobial prescriptions for acute lower respiratory tract infections was 16.9% (95% CI, 1.4%-29.4%).

During the first 3 months of life, for every 100 infants born, maternal vaccination prevented 3.6 courses of antimicrobials in high-income countries (20.2% of all antimicrobial prescribing), and 5.1 courses in low- and middle-income countries (10.9% of all antimicrobial prescribing).

In addition to finding that lower respiratory tract infections accounted for 69%-73% of all antimicrobial prescribing prevented by maternal vaccination, the researchers found marked vaccine efficacy (71.3% [95% CI, 28.1%-88.6%]) against acute otitis media–associated antimicrobial prescription in infants in high-income countries.
 

RSV vaccine is ‘one of our best investments’

RSV, the authors explain, is a major cause of upper and lower respiratory tract infections that develop as a single agent or along with bacterial pathogens.

“With decreases in bacterial pneumonia following the introduction of the pneumococcal conjugate vaccine, a vaccine against RSV represents one of our best investments to lower the burden of respiratory infections in children,” Dr. Laxminarayan said in a press release.

“These findings are not unexpected because viral infections can trigger bacterial infections such as otitis, and reducing viral infections will reduce bacterial infections,” Dr. Edwards said. “Also, viral infections are often treated with antibiotics because the provider cannot rule out a bacterial infection.”

She acknowledged the value of investigating multiple outcomes but added that “the study was underpowered to assess the full impact of the antibiotics.”

“If a more effective RSV vaccine can be designed, the impact on reducing antibiotic use will likely be even greater,” Dr. Edwards advised. “Also, the vaccine was not highly effective in preventing RSV pneumonia. If it had been more effective, the antibiotic impact would likely have been greater.”

The authors acknowledged the study’s limitations. “Results of this post hoc secondary analysis should be viewed as hypothesis generating, as the trial was not powered for determination of effects against antimicrobial prescribing, and our analyses were not adjusted for multiplicity,” they write, and they joined Dr. Edwards in recommending further related research.

First author Joseph A. Lewnard, PhD, declares financial support from Pfizer unrelated to this research, three authors are employees of Novavax, and Dr. Laxminarayan has disclosed no relevant financial relationships. Dr. Edwards reports funding from the National Institutes of Health and the Centers for Disease Control and Prevention; consultancy to BioNEt and IBM; membership on data safety and monitoring boards for Pfizer, Sanofi, GSK, Merck, X-4 Pharma, Roche, and Seqirus. The Bill & Melinda Gates Foundation supported the study.

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

Babies born to moms who were vaccinated against respiratory syncytial virus (RSV) while pregnant appear to need fewer antimicrobial prescriptions than babies of unvaccinated moms, according to authors of a recent study.

To fight antimicrobial resistance, we need to use fewer antimicrobial drugs, the authors write in Proceedings of the National Academy of Sciences.

“In this study, an RSV vaccine was administered to pregnant women to prevent infection in their infants by the transfer of protective antibody to the infant,” Kathryn M. Edwards, MD, a professor of pediatrics and the scientific director of the Vanderbilt vaccine research program at Vanderbilt University in Nashville, Tenn., told this news organization. Dr. Edwards was not involved in the study.

“The authors investigated the impact of the vaccine on the use of antibiotics in infants during the first 90 days of life,” Dr. Edwards added in an email. “They found that the use of antibiotics was less in infants born to mothers who received the RSV vaccine than in infants born to mothers who received placebo. … They suggest that reducing RSV infection in infants will reduce respiratory infections that trigger antibiotic use.”

Senior author Ramanan Laxminarayan, PhD, MPH, director and senior fellow at the Center for Disease Dynamics, Economics & Policy in Washington and his colleagues conducted a secondary analysis of a double-blind, randomized controlled trial at 87 sites in 11 countries on several continents.

In the original study, which was conducted between December 2015 and May 2018, 3,005 maternal participants and 2,978 infant participants received the experimental RSV F vaccine, and 1,573 maternal participants and 1,546 infants received a placebo shot. Baseline characteristics of mothers and infants were well balanced, according to the authors.

In the current study, infants born to mothers who received the RSV vaccine were found to be 12.9% (95% confidence interval, 1.3%-23.1%) less likely to be prescribed antimicrobials during their first 3 months of life, compared with infants whose mothers received placebo. Vaccine efficacy against antimicrobial prescriptions for acute lower respiratory tract infections was 16.9% (95% CI, 1.4%-29.4%).

During the first 3 months of life, for every 100 infants born, maternal vaccination prevented 3.6 courses of antimicrobials in high-income countries (20.2% of all antimicrobial prescribing), and 5.1 courses in low- and middle-income countries (10.9% of all antimicrobial prescribing).

In addition to finding that lower respiratory tract infections accounted for 69%-73% of all antimicrobial prescribing prevented by maternal vaccination, the researchers found marked vaccine efficacy (71.3% [95% CI, 28.1%-88.6%]) against acute otitis media–associated antimicrobial prescription in infants in high-income countries.
 

RSV vaccine is ‘one of our best investments’

RSV, the authors explain, is a major cause of upper and lower respiratory tract infections that develop as a single agent or along with bacterial pathogens.

“With decreases in bacterial pneumonia following the introduction of the pneumococcal conjugate vaccine, a vaccine against RSV represents one of our best investments to lower the burden of respiratory infections in children,” Dr. Laxminarayan said in a press release.

“These findings are not unexpected because viral infections can trigger bacterial infections such as otitis, and reducing viral infections will reduce bacterial infections,” Dr. Edwards said. “Also, viral infections are often treated with antibiotics because the provider cannot rule out a bacterial infection.”

She acknowledged the value of investigating multiple outcomes but added that “the study was underpowered to assess the full impact of the antibiotics.”

“If a more effective RSV vaccine can be designed, the impact on reducing antibiotic use will likely be even greater,” Dr. Edwards advised. “Also, the vaccine was not highly effective in preventing RSV pneumonia. If it had been more effective, the antibiotic impact would likely have been greater.”

The authors acknowledged the study’s limitations. “Results of this post hoc secondary analysis should be viewed as hypothesis generating, as the trial was not powered for determination of effects against antimicrobial prescribing, and our analyses were not adjusted for multiplicity,” they write, and they joined Dr. Edwards in recommending further related research.

First author Joseph A. Lewnard, PhD, declares financial support from Pfizer unrelated to this research, three authors are employees of Novavax, and Dr. Laxminarayan has disclosed no relevant financial relationships. Dr. Edwards reports funding from the National Institutes of Health and the Centers for Disease Control and Prevention; consultancy to BioNEt and IBM; membership on data safety and monitoring boards for Pfizer, Sanofi, GSK, Merck, X-4 Pharma, Roche, and Seqirus. The Bill & Melinda Gates Foundation supported the study.

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

Babies born to moms who were vaccinated against respiratory syncytial virus (RSV) while pregnant appear to need fewer antimicrobial prescriptions than babies of unvaccinated moms, according to authors of a recent study.

To fight antimicrobial resistance, we need to use fewer antimicrobial drugs, the authors write in Proceedings of the National Academy of Sciences.

“In this study, an RSV vaccine was administered to pregnant women to prevent infection in their infants by the transfer of protective antibody to the infant,” Kathryn M. Edwards, MD, a professor of pediatrics and the scientific director of the Vanderbilt vaccine research program at Vanderbilt University in Nashville, Tenn., told this news organization. Dr. Edwards was not involved in the study.

“The authors investigated the impact of the vaccine on the use of antibiotics in infants during the first 90 days of life,” Dr. Edwards added in an email. “They found that the use of antibiotics was less in infants born to mothers who received the RSV vaccine than in infants born to mothers who received placebo. … They suggest that reducing RSV infection in infants will reduce respiratory infections that trigger antibiotic use.”

Senior author Ramanan Laxminarayan, PhD, MPH, director and senior fellow at the Center for Disease Dynamics, Economics & Policy in Washington and his colleagues conducted a secondary analysis of a double-blind, randomized controlled trial at 87 sites in 11 countries on several continents.

In the original study, which was conducted between December 2015 and May 2018, 3,005 maternal participants and 2,978 infant participants received the experimental RSV F vaccine, and 1,573 maternal participants and 1,546 infants received a placebo shot. Baseline characteristics of mothers and infants were well balanced, according to the authors.

In the current study, infants born to mothers who received the RSV vaccine were found to be 12.9% (95% confidence interval, 1.3%-23.1%) less likely to be prescribed antimicrobials during their first 3 months of life, compared with infants whose mothers received placebo. Vaccine efficacy against antimicrobial prescriptions for acute lower respiratory tract infections was 16.9% (95% CI, 1.4%-29.4%).

During the first 3 months of life, for every 100 infants born, maternal vaccination prevented 3.6 courses of antimicrobials in high-income countries (20.2% of all antimicrobial prescribing), and 5.1 courses in low- and middle-income countries (10.9% of all antimicrobial prescribing).

In addition to finding that lower respiratory tract infections accounted for 69%-73% of all antimicrobial prescribing prevented by maternal vaccination, the researchers found marked vaccine efficacy (71.3% [95% CI, 28.1%-88.6%]) against acute otitis media–associated antimicrobial prescription in infants in high-income countries.
 

RSV vaccine is ‘one of our best investments’

RSV, the authors explain, is a major cause of upper and lower respiratory tract infections that develop as a single agent or along with bacterial pathogens.

“With decreases in bacterial pneumonia following the introduction of the pneumococcal conjugate vaccine, a vaccine against RSV represents one of our best investments to lower the burden of respiratory infections in children,” Dr. Laxminarayan said in a press release.

“These findings are not unexpected because viral infections can trigger bacterial infections such as otitis, and reducing viral infections will reduce bacterial infections,” Dr. Edwards said. “Also, viral infections are often treated with antibiotics because the provider cannot rule out a bacterial infection.”

She acknowledged the value of investigating multiple outcomes but added that “the study was underpowered to assess the full impact of the antibiotics.”

“If a more effective RSV vaccine can be designed, the impact on reducing antibiotic use will likely be even greater,” Dr. Edwards advised. “Also, the vaccine was not highly effective in preventing RSV pneumonia. If it had been more effective, the antibiotic impact would likely have been greater.”

The authors acknowledged the study’s limitations. “Results of this post hoc secondary analysis should be viewed as hypothesis generating, as the trial was not powered for determination of effects against antimicrobial prescribing, and our analyses were not adjusted for multiplicity,” they write, and they joined Dr. Edwards in recommending further related research.

First author Joseph A. Lewnard, PhD, declares financial support from Pfizer unrelated to this research, three authors are employees of Novavax, and Dr. Laxminarayan has disclosed no relevant financial relationships. Dr. Edwards reports funding from the National Institutes of Health and the Centers for Disease Control and Prevention; consultancy to BioNEt and IBM; membership on data safety and monitoring boards for Pfizer, Sanofi, GSK, Merck, X-4 Pharma, Roche, and Seqirus. The Bill & Melinda Gates Foundation supported the study.

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

Scientists are trying different approaches to developing vaccines against norovirus, seeking to replicate the success seen in developing shots against rotavirus.

Speaking at the 12th World Congress of the World Society for Pediatric Infectious Diseases (WSPID), Miguel O’Ryan, MD, of the University of Chile, Santiago, presented an overview of candidate vaccines. Dr. O’Ryan has been involved for many years with research on rotavirus vaccines and has branched into work with the somewhat similar norovirus.

With advances in preventing rotavirus, norovirus has emerged in recent years as a leading cause of acute gastroenteritis (AGE) in most countries worldwide. It’s associated with almost 20% of all acute diarrheal cases globally and with an estimated 685 million episodes and 212,000 deaths annually, Dr. O’Ryan and coauthors reported in a review in the journal Viruses.

If successful, norovirus vaccines may be used someday to prevent outbreaks among military personnel, as this contagious virus has the potential to disrupt missions, Dr. O’Ryan and coauthors wrote. They also said people might consider getting norovirus vaccines ahead of trips to prevent traveler’s diarrhea. But most importantly, these kinds of vaccines could reduce diarrhea-associated hospitalizations and deaths of children. 

Takeda Pharmaceutical Company, for whom Dr. O’Ryan has done consulting, last year announced a collaboration with Frazier Healthcare Partners to launch HilleVax. Based in Boston, the company is intended to commercialize Takeda’s norovirus vaccine candidate.

The Takeda-HilleVax candidate vaccine injection has advanced as far as phase 2 studies, including a test done over two winter seasons in U.S. Navy recruits. Takeda and U.S. Navy scientists reported in 2020 in the journal Vaccine that the primary efficacy outcome for this test could not be evaluated due to an unexpectedly low number of cases of norovirus. Still, data taken from this study indicate that the vaccine induces a broad immune response, the scientists reported.

In his WSPID presentation, Dr. O’Ryan also mentioned an oral norovirus vaccine candidate that the company Vaxart is developing, referring to this as a “very interesting approach.” 
 

Betting on the gut

Based in South San Francisco, California, Vaxart is pursuing a theory that a vaccine designed to generate mucosal antibodies locally in the intestine, in addition to systemic antibodies in the blood, may better protect against norovirus infection than an injectable vaccine.

“A key ability to protect against norovirus needs to come from an intestinal immune response, and injected vaccines don’t give those very well,” Sean Tucker, PhD, the founder and chief scientific officer of Vaxart, told this news organization in an interview. “We think that’s one of the reasons why our oral approaches can have significant advantages.”

Challenges to developing a norovirus vaccine have included a lack of good animal models to use in research and a lack of an ability to grow the virus well in cell culture, Dr. Tucker said.

Vaxart experienced disruptions in its research during the early stages of the pandemic but has since picked up the pace of its efforts to develop its oral vaccine, Dr. Tucker said during the interview.

In a recent filing with the Securities and Exchange Commission, Vaxart said in early 2021 it resumed its norovirus vaccine program by initiating three clinical studies. These included a phase 1b placebo-controlled dose ranging study in healthy elderly adults aged 55-80. Data from these trials may be unveiled in the coming months.

Vaxart said that this year it has already initiated a phase 2 norovirus challenge study, which will evaluate safety, immunogenicity, and clinical efficacy of a vaccine candidate against placebo.

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

Scientists are trying different approaches to developing vaccines against norovirus, seeking to replicate the success seen in developing shots against rotavirus.

Speaking at the 12th World Congress of the World Society for Pediatric Infectious Diseases (WSPID), Miguel O’Ryan, MD, of the University of Chile, Santiago, presented an overview of candidate vaccines. Dr. O’Ryan has been involved for many years with research on rotavirus vaccines and has branched into work with the somewhat similar norovirus.

With advances in preventing rotavirus, norovirus has emerged in recent years as a leading cause of acute gastroenteritis (AGE) in most countries worldwide. It’s associated with almost 20% of all acute diarrheal cases globally and with an estimated 685 million episodes and 212,000 deaths annually, Dr. O’Ryan and coauthors reported in a review in the journal Viruses.

If successful, norovirus vaccines may be used someday to prevent outbreaks among military personnel, as this contagious virus has the potential to disrupt missions, Dr. O’Ryan and coauthors wrote. They also said people might consider getting norovirus vaccines ahead of trips to prevent traveler’s diarrhea. But most importantly, these kinds of vaccines could reduce diarrhea-associated hospitalizations and deaths of children. 

Takeda Pharmaceutical Company, for whom Dr. O’Ryan has done consulting, last year announced a collaboration with Frazier Healthcare Partners to launch HilleVax. Based in Boston, the company is intended to commercialize Takeda’s norovirus vaccine candidate.

The Takeda-HilleVax candidate vaccine injection has advanced as far as phase 2 studies, including a test done over two winter seasons in U.S. Navy recruits. Takeda and U.S. Navy scientists reported in 2020 in the journal Vaccine that the primary efficacy outcome for this test could not be evaluated due to an unexpectedly low number of cases of norovirus. Still, data taken from this study indicate that the vaccine induces a broad immune response, the scientists reported.

In his WSPID presentation, Dr. O’Ryan also mentioned an oral norovirus vaccine candidate that the company Vaxart is developing, referring to this as a “very interesting approach.” 
 

Betting on the gut

Based in South San Francisco, California, Vaxart is pursuing a theory that a vaccine designed to generate mucosal antibodies locally in the intestine, in addition to systemic antibodies in the blood, may better protect against norovirus infection than an injectable vaccine.

“A key ability to protect against norovirus needs to come from an intestinal immune response, and injected vaccines don’t give those very well,” Sean Tucker, PhD, the founder and chief scientific officer of Vaxart, told this news organization in an interview. “We think that’s one of the reasons why our oral approaches can have significant advantages.”

Challenges to developing a norovirus vaccine have included a lack of good animal models to use in research and a lack of an ability to grow the virus well in cell culture, Dr. Tucker said.

Vaxart experienced disruptions in its research during the early stages of the pandemic but has since picked up the pace of its efforts to develop its oral vaccine, Dr. Tucker said during the interview.

In a recent filing with the Securities and Exchange Commission, Vaxart said in early 2021 it resumed its norovirus vaccine program by initiating three clinical studies. These included a phase 1b placebo-controlled dose ranging study in healthy elderly adults aged 55-80. Data from these trials may be unveiled in the coming months.

Vaxart said that this year it has already initiated a phase 2 norovirus challenge study, which will evaluate safety, immunogenicity, and clinical efficacy of a vaccine candidate against placebo.

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

Scientists are trying different approaches to developing vaccines against norovirus, seeking to replicate the success seen in developing shots against rotavirus.

Speaking at the 12th World Congress of the World Society for Pediatric Infectious Diseases (WSPID), Miguel O’Ryan, MD, of the University of Chile, Santiago, presented an overview of candidate vaccines. Dr. O’Ryan has been involved for many years with research on rotavirus vaccines and has branched into work with the somewhat similar norovirus.

With advances in preventing rotavirus, norovirus has emerged in recent years as a leading cause of acute gastroenteritis (AGE) in most countries worldwide. It’s associated with almost 20% of all acute diarrheal cases globally and with an estimated 685 million episodes and 212,000 deaths annually, Dr. O’Ryan and coauthors reported in a review in the journal Viruses.

If successful, norovirus vaccines may be used someday to prevent outbreaks among military personnel, as this contagious virus has the potential to disrupt missions, Dr. O’Ryan and coauthors wrote. They also said people might consider getting norovirus vaccines ahead of trips to prevent traveler’s diarrhea. But most importantly, these kinds of vaccines could reduce diarrhea-associated hospitalizations and deaths of children. 

Takeda Pharmaceutical Company, for whom Dr. O’Ryan has done consulting, last year announced a collaboration with Frazier Healthcare Partners to launch HilleVax. Based in Boston, the company is intended to commercialize Takeda’s norovirus vaccine candidate.

The Takeda-HilleVax candidate vaccine injection has advanced as far as phase 2 studies, including a test done over two winter seasons in U.S. Navy recruits. Takeda and U.S. Navy scientists reported in 2020 in the journal Vaccine that the primary efficacy outcome for this test could not be evaluated due to an unexpectedly low number of cases of norovirus. Still, data taken from this study indicate that the vaccine induces a broad immune response, the scientists reported.

In his WSPID presentation, Dr. O’Ryan also mentioned an oral norovirus vaccine candidate that the company Vaxart is developing, referring to this as a “very interesting approach.” 
 

Betting on the gut

Based in South San Francisco, California, Vaxart is pursuing a theory that a vaccine designed to generate mucosal antibodies locally in the intestine, in addition to systemic antibodies in the blood, may better protect against norovirus infection than an injectable vaccine.

“A key ability to protect against norovirus needs to come from an intestinal immune response, and injected vaccines don’t give those very well,” Sean Tucker, PhD, the founder and chief scientific officer of Vaxart, told this news organization in an interview. “We think that’s one of the reasons why our oral approaches can have significant advantages.”

Challenges to developing a norovirus vaccine have included a lack of good animal models to use in research and a lack of an ability to grow the virus well in cell culture, Dr. Tucker said.

Vaxart experienced disruptions in its research during the early stages of the pandemic but has since picked up the pace of its efforts to develop its oral vaccine, Dr. Tucker said during the interview.

In a recent filing with the Securities and Exchange Commission, Vaxart said in early 2021 it resumed its norovirus vaccine program by initiating three clinical studies. These included a phase 1b placebo-controlled dose ranging study in healthy elderly adults aged 55-80. Data from these trials may be unveiled in the coming months.

Vaxart said that this year it has already initiated a phase 2 norovirus challenge study, which will evaluate safety, immunogenicity, and clinical efficacy of a vaccine candidate against placebo.

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

It’s now known that tinnitus may be an unexpected side effect of SARS-CoV-2 vaccination, and there is an urgent need to understand the precise mechanisms and best treatment for vaccine-associated tinnitus, researchers say.

As of mid-September 2021, 12,247 cases of tinnitus, or ringing in the ears, following COVID-19 vaccination had been reported to the Vaccine Adverse Event Reporting System of the U.S. Centers for Disease Control and Prevention.

“Despite several cases of tinnitus being reported following SARS-CoV-2 vaccination, the precise pathophysiology is still not clear,” write Syed Hassan Ahmed, 3rd-year MBBS student, Dow University of Health Sciences, Karachi, Pakistan, and coauthors.

The researchers review what is known and unknown about SARS-CoV-2 vaccine-associated tinnitus in an article published online Feb. 11 in Annals of Medicine and Surgery.
 

Molecular mimicry?

The researchers say cross-reactivity between anti-spike SARS-CoV-2 antibodies and otologic antigens is one possibility, based on the mechanisms behind other COVID-19 vaccine–induced disorders and the phenomenon of molecular mimicry.

“The heptapeptide resemblance between coronavirus spike glycoprotein and numerous human proteins further supports molecular mimicry as a potential mechanism behind such vaccine-induced disorders,” they write.

Anti-spike antibodies may react with antigens anywhere along the auditory pathway and fuel an inflammatory reaction, they point out.

“Therefore, understanding the phenomenon of cross-reactivity and molecular mimicry may be helpful in postulating potential treatment behind not only tinnitus but also the rare events of vaccination associated hearing loss and other otologic manifestations,” the authors say.

Genetic predispositions and associated conditions may also play a significant role in determining whether an individual develops vaccine-induced tinnitus.

Stress and anxiety following COVID vaccination may also play a role, inasmuch as anxiety-related adverse events following vaccination have been reported. Vaccine-related anxiety as a potential cause of tinnitus developing after vaccination needs to be explored, they write.
 

Jury out on best management

How best to manage COVID vaccine-associated tinnitus also remains unclear, but it starts with a well-established diagnosis, the authors say.

A well-focused and detailed history and examination are essential, with particular emphasis placed on preexisting health conditions, specifically, autoimmune diseases, such as Hashimoto thyroiditis; otologic conditions, such as sensorineural hearing loss; glaucoma; and psychological well-being. According to the review, patients often present with a history of one or more of these disorders.

“However, any such association has not yet been established and requires further investigation to be concluded as potential risk factors for vaccine-induced tinnitus,” they caution.

Routine cranial nerve examination, otoscopy, Weber test, and Rinne test, which are used for tinnitus diagnosis in general, may be helpful for confirmation of vaccine-associated tinnitus.

Owing to the significant association between tinnitus and hearing impairment, audiology should also performed, the authors say.

Although treatments for non–vaccine-induced tinnitus vary significantly, corticosteroids are the top treatment choice for SARS-CoV-2 vaccine-induced tinnitus reported in the literature.

Trials of other drug and nondrug interventions that may uniquely help with vaccine-associated tinnitus are urgently needed, the authors say.

Summing up, the reviewers say, “Although the incidence of COVID-19 vaccine-associated tinnitus is rare, there is an overwhelming need to discern the precise pathophysiology and clinical management as a better understanding of adverse events may help in encountering vaccine hesitancy and hence fostering the COVID-19 global vaccination program.

“Despite the incidence of adverse events, the benefits of the SARS-CoV-2 vaccine in reducing hospitalization and deaths continue to outweigh the rare ramifications,” they conclude.

The research had no specific funding. The authors have disclosed no relevant financial relationships.

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

It’s now known that tinnitus may be an unexpected side effect of SARS-CoV-2 vaccination, and there is an urgent need to understand the precise mechanisms and best treatment for vaccine-associated tinnitus, researchers say.

As of mid-September 2021, 12,247 cases of tinnitus, or ringing in the ears, following COVID-19 vaccination had been reported to the Vaccine Adverse Event Reporting System of the U.S. Centers for Disease Control and Prevention.

“Despite several cases of tinnitus being reported following SARS-CoV-2 vaccination, the precise pathophysiology is still not clear,” write Syed Hassan Ahmed, 3rd-year MBBS student, Dow University of Health Sciences, Karachi, Pakistan, and coauthors.

The researchers review what is known and unknown about SARS-CoV-2 vaccine-associated tinnitus in an article published online Feb. 11 in Annals of Medicine and Surgery.
 

Molecular mimicry?

The researchers say cross-reactivity between anti-spike SARS-CoV-2 antibodies and otologic antigens is one possibility, based on the mechanisms behind other COVID-19 vaccine–induced disorders and the phenomenon of molecular mimicry.

“The heptapeptide resemblance between coronavirus spike glycoprotein and numerous human proteins further supports molecular mimicry as a potential mechanism behind such vaccine-induced disorders,” they write.

Anti-spike antibodies may react with antigens anywhere along the auditory pathway and fuel an inflammatory reaction, they point out.

“Therefore, understanding the phenomenon of cross-reactivity and molecular mimicry may be helpful in postulating potential treatment behind not only tinnitus but also the rare events of vaccination associated hearing loss and other otologic manifestations,” the authors say.

Genetic predispositions and associated conditions may also play a significant role in determining whether an individual develops vaccine-induced tinnitus.

Stress and anxiety following COVID vaccination may also play a role, inasmuch as anxiety-related adverse events following vaccination have been reported. Vaccine-related anxiety as a potential cause of tinnitus developing after vaccination needs to be explored, they write.
 

Jury out on best management

How best to manage COVID vaccine-associated tinnitus also remains unclear, but it starts with a well-established diagnosis, the authors say.

A well-focused and detailed history and examination are essential, with particular emphasis placed on preexisting health conditions, specifically, autoimmune diseases, such as Hashimoto thyroiditis; otologic conditions, such as sensorineural hearing loss; glaucoma; and psychological well-being. According to the review, patients often present with a history of one or more of these disorders.

“However, any such association has not yet been established and requires further investigation to be concluded as potential risk factors for vaccine-induced tinnitus,” they caution.

Routine cranial nerve examination, otoscopy, Weber test, and Rinne test, which are used for tinnitus diagnosis in general, may be helpful for confirmation of vaccine-associated tinnitus.

Owing to the significant association between tinnitus and hearing impairment, audiology should also performed, the authors say.

Although treatments for non–vaccine-induced tinnitus vary significantly, corticosteroids are the top treatment choice for SARS-CoV-2 vaccine-induced tinnitus reported in the literature.

Trials of other drug and nondrug interventions that may uniquely help with vaccine-associated tinnitus are urgently needed, the authors say.

Summing up, the reviewers say, “Although the incidence of COVID-19 vaccine-associated tinnitus is rare, there is an overwhelming need to discern the precise pathophysiology and clinical management as a better understanding of adverse events may help in encountering vaccine hesitancy and hence fostering the COVID-19 global vaccination program.

“Despite the incidence of adverse events, the benefits of the SARS-CoV-2 vaccine in reducing hospitalization and deaths continue to outweigh the rare ramifications,” they conclude.

The research had no specific funding. The authors have disclosed no relevant financial relationships.

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

It’s now known that tinnitus may be an unexpected side effect of SARS-CoV-2 vaccination, and there is an urgent need to understand the precise mechanisms and best treatment for vaccine-associated tinnitus, researchers say.

As of mid-September 2021, 12,247 cases of tinnitus, or ringing in the ears, following COVID-19 vaccination had been reported to the Vaccine Adverse Event Reporting System of the U.S. Centers for Disease Control and Prevention.

“Despite several cases of tinnitus being reported following SARS-CoV-2 vaccination, the precise pathophysiology is still not clear,” write Syed Hassan Ahmed, 3rd-year MBBS student, Dow University of Health Sciences, Karachi, Pakistan, and coauthors.

The researchers review what is known and unknown about SARS-CoV-2 vaccine-associated tinnitus in an article published online Feb. 11 in Annals of Medicine and Surgery.
 

Molecular mimicry?

The researchers say cross-reactivity between anti-spike SARS-CoV-2 antibodies and otologic antigens is one possibility, based on the mechanisms behind other COVID-19 vaccine–induced disorders and the phenomenon of molecular mimicry.

“The heptapeptide resemblance between coronavirus spike glycoprotein and numerous human proteins further supports molecular mimicry as a potential mechanism behind such vaccine-induced disorders,” they write.

Anti-spike antibodies may react with antigens anywhere along the auditory pathway and fuel an inflammatory reaction, they point out.

“Therefore, understanding the phenomenon of cross-reactivity and molecular mimicry may be helpful in postulating potential treatment behind not only tinnitus but also the rare events of vaccination associated hearing loss and other otologic manifestations,” the authors say.

Genetic predispositions and associated conditions may also play a significant role in determining whether an individual develops vaccine-induced tinnitus.

Stress and anxiety following COVID vaccination may also play a role, inasmuch as anxiety-related adverse events following vaccination have been reported. Vaccine-related anxiety as a potential cause of tinnitus developing after vaccination needs to be explored, they write.
 

Jury out on best management

How best to manage COVID vaccine-associated tinnitus also remains unclear, but it starts with a well-established diagnosis, the authors say.

A well-focused and detailed history and examination are essential, with particular emphasis placed on preexisting health conditions, specifically, autoimmune diseases, such as Hashimoto thyroiditis; otologic conditions, such as sensorineural hearing loss; glaucoma; and psychological well-being. According to the review, patients often present with a history of one or more of these disorders.

“However, any such association has not yet been established and requires further investigation to be concluded as potential risk factors for vaccine-induced tinnitus,” they caution.

Routine cranial nerve examination, otoscopy, Weber test, and Rinne test, which are used for tinnitus diagnosis in general, may be helpful for confirmation of vaccine-associated tinnitus.

Owing to the significant association between tinnitus and hearing impairment, audiology should also performed, the authors say.

Although treatments for non–vaccine-induced tinnitus vary significantly, corticosteroids are the top treatment choice for SARS-CoV-2 vaccine-induced tinnitus reported in the literature.

Trials of other drug and nondrug interventions that may uniquely help with vaccine-associated tinnitus are urgently needed, the authors say.

Summing up, the reviewers say, “Although the incidence of COVID-19 vaccine-associated tinnitus is rare, there is an overwhelming need to discern the precise pathophysiology and clinical management as a better understanding of adverse events may help in encountering vaccine hesitancy and hence fostering the COVID-19 global vaccination program.

“Despite the incidence of adverse events, the benefits of the SARS-CoV-2 vaccine in reducing hospitalization and deaths continue to outweigh the rare ramifications,” they conclude.

The research had no specific funding. The authors have disclosed no relevant financial relationships.

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

Adults with a congenital heart defect (CHD) are at increased risk for serious illness and death when hospitalized with COVID-19, making vaccination and other preventive measures even important in this population, say researchers with the Centers for Disease Control and Prevention.

“We found that hospitalized patients with heart defects are up to twice as likely to have critical outcomes of COVID-19 illness (admission to the intensive care unit, use of a ventilator to help with breathing, or death) compared to hospitalized COVID-19 patients without heart defects,” Karrie Downing, MPH, epidemiologist, with the CDC’s National Center on Birth Defects and Developmental Disabilities, said in an interview.

“Additionally, we learned that people with hearts defects who were older or who also had other conditions like heart failure, pulmonary hypertension, Down syndrome, diabetes, or obesity were the most likely to have critical COVID-19 illness, but children and adults with heart defects without these other conditions were still at increased risk,” Ms. Downing said.

The message for health care providers is clear: “Encourage your patients with heart defects to get vaccinated and discuss with your patients the need for other preventive measures to avoid infection that may progress to severe COVID-19 illness,” Ms. Downing added.

The study was published online March 7, 2022, in Circulation.

The researchers analyzed data on 235,638 patients hospitalized with COVID-19 between March 2020 and January 2021, including 421 (0.2%) with CHD. Most CHD patients were older than 30 years (73%) and 61% were men, with 55% non-Hispanic white, 19% Hispanic and 16% non-Hispanic Black.

Overall, 68% of CHD patients had at least one comorbidity, as did 59% of patients without CHD.

Rates of ICU admission were higher in the CHD group (54% vs. 43%), as were rates of invasive mechanical ventilation (24% vs. 15%) and in-hospital death (11% vs. 7%).

After accounting for patient characteristics, ICU admission, invasive mechanical ventilation and death were more prevalent among COVID-19 patients with rather than without CHD, with adjusted prevalence ratios of 1.4, 1.8 and 2.0, respectively.

When stratified by high-risk characteristics, prevalence estimates for ICU admission, invasive mechanical ventilation and death remained higher among patients with COVID-19 and CHD across nearly all strata, including younger age groups and those without heart failure, pulmonary hypertension, Down syndrome, diabetes, or obesity, the researchers reported.

Ms. Downing said more work is needed to identify why the clinical course of COVID-19 disease results in admission to the ICU, the need for a ventilator, or death for some hospitalized patients with CHD and not for others.

“There could be a number of social, environmental, economic, medical, and genetic factors playing a role. But staying up to date with COVID-19 vaccines and following preventive measures for COVID-19 are effective ways to reduce the risk of severe illness from COVID-19,” Ms. Downing said.

The study had no specific funding. The authors reported no relevant disclosures.

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

Adults with a congenital heart defect (CHD) are at increased risk for serious illness and death when hospitalized with COVID-19, making vaccination and other preventive measures even important in this population, say researchers with the Centers for Disease Control and Prevention.

“We found that hospitalized patients with heart defects are up to twice as likely to have critical outcomes of COVID-19 illness (admission to the intensive care unit, use of a ventilator to help with breathing, or death) compared to hospitalized COVID-19 patients without heart defects,” Karrie Downing, MPH, epidemiologist, with the CDC’s National Center on Birth Defects and Developmental Disabilities, said in an interview.

“Additionally, we learned that people with hearts defects who were older or who also had other conditions like heart failure, pulmonary hypertension, Down syndrome, diabetes, or obesity were the most likely to have critical COVID-19 illness, but children and adults with heart defects without these other conditions were still at increased risk,” Ms. Downing said.

The message for health care providers is clear: “Encourage your patients with heart defects to get vaccinated and discuss with your patients the need for other preventive measures to avoid infection that may progress to severe COVID-19 illness,” Ms. Downing added.

The study was published online March 7, 2022, in Circulation.

The researchers analyzed data on 235,638 patients hospitalized with COVID-19 between March 2020 and January 2021, including 421 (0.2%) with CHD. Most CHD patients were older than 30 years (73%) and 61% were men, with 55% non-Hispanic white, 19% Hispanic and 16% non-Hispanic Black.

Overall, 68% of CHD patients had at least one comorbidity, as did 59% of patients without CHD.

Rates of ICU admission were higher in the CHD group (54% vs. 43%), as were rates of invasive mechanical ventilation (24% vs. 15%) and in-hospital death (11% vs. 7%).

After accounting for patient characteristics, ICU admission, invasive mechanical ventilation and death were more prevalent among COVID-19 patients with rather than without CHD, with adjusted prevalence ratios of 1.4, 1.8 and 2.0, respectively.

When stratified by high-risk characteristics, prevalence estimates for ICU admission, invasive mechanical ventilation and death remained higher among patients with COVID-19 and CHD across nearly all strata, including younger age groups and those without heart failure, pulmonary hypertension, Down syndrome, diabetes, or obesity, the researchers reported.

Ms. Downing said more work is needed to identify why the clinical course of COVID-19 disease results in admission to the ICU, the need for a ventilator, or death for some hospitalized patients with CHD and not for others.

“There could be a number of social, environmental, economic, medical, and genetic factors playing a role. But staying up to date with COVID-19 vaccines and following preventive measures for COVID-19 are effective ways to reduce the risk of severe illness from COVID-19,” Ms. Downing said.

The study had no specific funding. The authors reported no relevant disclosures.

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

Adults with a congenital heart defect (CHD) are at increased risk for serious illness and death when hospitalized with COVID-19, making vaccination and other preventive measures even important in this population, say researchers with the Centers for Disease Control and Prevention.

“We found that hospitalized patients with heart defects are up to twice as likely to have critical outcomes of COVID-19 illness (admission to the intensive care unit, use of a ventilator to help with breathing, or death) compared to hospitalized COVID-19 patients without heart defects,” Karrie Downing, MPH, epidemiologist, with the CDC’s National Center on Birth Defects and Developmental Disabilities, said in an interview.

“Additionally, we learned that people with hearts defects who were older or who also had other conditions like heart failure, pulmonary hypertension, Down syndrome, diabetes, or obesity were the most likely to have critical COVID-19 illness, but children and adults with heart defects without these other conditions were still at increased risk,” Ms. Downing said.

The message for health care providers is clear: “Encourage your patients with heart defects to get vaccinated and discuss with your patients the need for other preventive measures to avoid infection that may progress to severe COVID-19 illness,” Ms. Downing added.

The study was published online March 7, 2022, in Circulation.

The researchers analyzed data on 235,638 patients hospitalized with COVID-19 between March 2020 and January 2021, including 421 (0.2%) with CHD. Most CHD patients were older than 30 years (73%) and 61% were men, with 55% non-Hispanic white, 19% Hispanic and 16% non-Hispanic Black.

Overall, 68% of CHD patients had at least one comorbidity, as did 59% of patients without CHD.

Rates of ICU admission were higher in the CHD group (54% vs. 43%), as were rates of invasive mechanical ventilation (24% vs. 15%) and in-hospital death (11% vs. 7%).

After accounting for patient characteristics, ICU admission, invasive mechanical ventilation and death were more prevalent among COVID-19 patients with rather than without CHD, with adjusted prevalence ratios of 1.4, 1.8 and 2.0, respectively.

When stratified by high-risk characteristics, prevalence estimates for ICU admission, invasive mechanical ventilation and death remained higher among patients with COVID-19 and CHD across nearly all strata, including younger age groups and those without heart failure, pulmonary hypertension, Down syndrome, diabetes, or obesity, the researchers reported.

Ms. Downing said more work is needed to identify why the clinical course of COVID-19 disease results in admission to the ICU, the need for a ventilator, or death for some hospitalized patients with CHD and not for others.

“There could be a number of social, environmental, economic, medical, and genetic factors playing a role. But staying up to date with COVID-19 vaccines and following preventive measures for COVID-19 are effective ways to reduce the risk of severe illness from COVID-19,” Ms. Downing said.

The study had no specific funding. The authors reported no relevant disclosures.

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

People taking immunosuppressive drugs benefit significantly from SARS-CoV-2 vaccines approved in the United States to prevent and reduce the severity of COVID-19, according to the first study to quantify the vaccines’ real-world effectiveness in this population.

Researchers’ analysis of the electronic medical records of more than 150,000 people in the University of Michigan’s health care system showed that even after becoming fully vaccinated, immunosuppressed individuals remain at higher risk for COVID-19 than are vaccinated people in the wider population who aren’t receiving immunosuppressive therapy. However, they still derive benefit from vaccination, particularly when bolstered with a booster dose.

BrianAJackson/Thinkstock

The study, published online in Annals of the Rheumatic Diseases, also claims to be the first to show that the Moderna (mRNA-1273) vaccine is as effective as the Pfizer-BioNTech (BNT162b2) vaccine for people taking immunosuppressants.

“Booster doses are effective and important for individuals on immunosuppressants,” corresponding author Lili Zhao, PhD, a research associate professor in biostatistics at the University of Michigan, Ann Arbor, said in an interview. “Previous studies focused mostly on the Pfizer vaccine, whereas our study is the first that also investigates the Moderna vaccine in a large, immunosuppressed population.”

The epidemiologic study included 154,519 fully vaccinated and unvaccinated adults in the Michigan Medicine electronic health record database. Participants were considered fully vaccinated if they were within 2 weeks of having received a second dose of the Pfizer-BioNTech and Moderna vaccines or the single-dose Johnson & Johnson (Ad26.COV2.S) vaccine. The study population included 5,536 immunosuppressed patients; of those, 4,283 were fully vaccinated, and 1,253 were unvaccinated.

The researchers focused on data collected from Jan. 1 to Dec. 7, 2021, so the study doesn’t cover the Omicron variant. “The conclusions for immunosuppressed individuals are likely to remain the same during the Omicron period,” Dr. Zhao said. “We are currently investigating this.” Johnson & Johnson paused production of its vaccine in February.

The researchers found that, among unvaccinated individuals, the immunosuppressed group had about a 40% higher risk of infection than did the immunocompetent patients (hazard ratio, 1.398; 95% confidence interval, 1.068-1.829; P = .0075) but a similar risk of COVID-19 hospitalization (HR, 0.951; 95% CI, 0.435-2.080; P = .9984). For the fully vaccinated, the gap was significantly wider: Immunosuppressed patients had more than double the risk of infection (HR, 2.173; 95% CI, 1.690-2.794; P < .0001) and almost five times the risk of hospitalization (HR, 4.861; 95% CI, 2.238-10.56; P < .0001), compared with immunocompetent patients.

However, among immunosuppressed individuals, the vaccinations significantly lowered risks, compared with not being vaccinated. There was a statistically significant 45% lower risk of infection (HR, 0.550; 95% CI, 0.387-0.781; P = .001) and similarly lower risk of hospitalization that did not reach statistical significance (HR, 0.534; 95% CI, 0.196-1.452; P = .3724).

When those immunosuppressed patients received a booster dose, their protection against COVID-19 improved, compared with their immunosuppressed counterparts who didn’t get a booster, with a 58% lower risk of infection after adjustment for age, gender, race, and Charlson Comorbidity Index (adjusted HR, 0.42; 95% CI, 0.24-0.76; P = .0037). The study included nearly 4 months of data after the Centers for Disease Control and Prevention recommended a booster dose of the Moderna and Pfizer-BioNTech vaccines for immunocompromised individuals in August 2021. Among the immunosuppressed patients, 38.5% had received a booster dose.

There also was no apparent difference in the effectiveness between the Moderna and Pfizer-BioNTech vaccines, with adjusted hazard ratios showing 41%-48% lower risk of infection. Too few individuals in the study were vaccinated with the Johnson & Johnson vaccine to enable a sufficiently powered calculation of its effectiveness.

Other studies reach similar conclusions

The study findings fall into line with other studies of patient populations on immunosuppressants. A retrospective cohort study of Veterans Affairs patients with inflammatory bowel disease who were taking immunosuppressants, published in Gastroenterology, found that full vaccination with either Moderna and Pfizer-BioNTech vaccines was about 80% effective. Another retrospective cohort study of data from the National COVID Cohort Collaborative, published in JAMA Internal Medicine, reported that full vaccination significantly reduced the risk of COVID-19 breakthrough infection regardless of immune status. Immunosuppressed patients in this study had higher rates of breakthrough infections than immunocompetent patients, but the disparities were in line with what Dr. Zhao and the University of Michigan researchers reported.

A review of 23 studies of COVID-19 vaccinations, published in Lancet Global Health, found that immunocompromised people – 1,722 of whom were included in the studies – had lower rates of producing antibodies after two vaccine doses than did immunocompetent people, ranging from 27% to 92%, depending on the nature of their immunocompromised status, compared with 99% for the immunocompetent.
 

Strengths and limitations

One strength of the Michigan study is the quality of data, which were drawn from the Michigan Medicine electronic health record, Dr. Zhao said. “So, we know who received the vaccine and who didn’t. We also have access to data on patient health conditions, such as comorbidities, in addition to demographic variables (age, gender, and race), which were controlled in making fair comparisons between immunosuppressants and immunocompetent groups.”

Alfred Kim, MD, PhD, an assistant professor of internal medicine and rheumatology at Washington University in St. Louis, who was not involved with the study, credited Dr. Zhao and associates for delivering the first data that specifically quantified COVID-19 risk reduction in a large study population. Although he noted that the large sample size and the design reduced the chances of confounding and were strengths, he said in an interview that “lumping” the patients taking immunosuppressive drugs into one group was a weakness of the study.

“Clearly, there are certain medications (B-cell depleters, mycophenolate, for example) that carry the greatest risk of poor antibody responses post vaccination,” he said. “One would have to guess that the greatest risk of breakthrough infections continues to be in those patients taking these high-risk medications.”

Another possible problem, which the authors acknowledged, is spotty SARS-CoV-2 testing of study participants – “a systemic issue,” Dr. Kim noted.

“The easiest and most durable way to reduce the risk of getting COVID-19 is through vaccination, period,” he said. “Now we have infection-rates data from a real-world study cohort to prove this. Furthermore, boosting clearly provides additional benefit to this population.”

The National Institute of Allergy and Infectious Diseases provided funding for the study. Dr. Zhao, Dr. Zhao’s coauthors, and Kim disclosed no relevant financial relationships.

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

People taking immunosuppressive drugs benefit significantly from SARS-CoV-2 vaccines approved in the United States to prevent and reduce the severity of COVID-19, according to the first study to quantify the vaccines’ real-world effectiveness in this population.

Researchers’ analysis of the electronic medical records of more than 150,000 people in the University of Michigan’s health care system showed that even after becoming fully vaccinated, immunosuppressed individuals remain at higher risk for COVID-19 than are vaccinated people in the wider population who aren’t receiving immunosuppressive therapy. However, they still derive benefit from vaccination, particularly when bolstered with a booster dose.

BrianAJackson/Thinkstock

The study, published online in Annals of the Rheumatic Diseases, also claims to be the first to show that the Moderna (mRNA-1273) vaccine is as effective as the Pfizer-BioNTech (BNT162b2) vaccine for people taking immunosuppressants.

“Booster doses are effective and important for individuals on immunosuppressants,” corresponding author Lili Zhao, PhD, a research associate professor in biostatistics at the University of Michigan, Ann Arbor, said in an interview. “Previous studies focused mostly on the Pfizer vaccine, whereas our study is the first that also investigates the Moderna vaccine in a large, immunosuppressed population.”

The epidemiologic study included 154,519 fully vaccinated and unvaccinated adults in the Michigan Medicine electronic health record database. Participants were considered fully vaccinated if they were within 2 weeks of having received a second dose of the Pfizer-BioNTech and Moderna vaccines or the single-dose Johnson & Johnson (Ad26.COV2.S) vaccine. The study population included 5,536 immunosuppressed patients; of those, 4,283 were fully vaccinated, and 1,253 were unvaccinated.

The researchers focused on data collected from Jan. 1 to Dec. 7, 2021, so the study doesn’t cover the Omicron variant. “The conclusions for immunosuppressed individuals are likely to remain the same during the Omicron period,” Dr. Zhao said. “We are currently investigating this.” Johnson & Johnson paused production of its vaccine in February.

The researchers found that, among unvaccinated individuals, the immunosuppressed group had about a 40% higher risk of infection than did the immunocompetent patients (hazard ratio, 1.398; 95% confidence interval, 1.068-1.829; P = .0075) but a similar risk of COVID-19 hospitalization (HR, 0.951; 95% CI, 0.435-2.080; P = .9984). For the fully vaccinated, the gap was significantly wider: Immunosuppressed patients had more than double the risk of infection (HR, 2.173; 95% CI, 1.690-2.794; P < .0001) and almost five times the risk of hospitalization (HR, 4.861; 95% CI, 2.238-10.56; P < .0001), compared with immunocompetent patients.

However, among immunosuppressed individuals, the vaccinations significantly lowered risks, compared with not being vaccinated. There was a statistically significant 45% lower risk of infection (HR, 0.550; 95% CI, 0.387-0.781; P = .001) and similarly lower risk of hospitalization that did not reach statistical significance (HR, 0.534; 95% CI, 0.196-1.452; P = .3724).

When those immunosuppressed patients received a booster dose, their protection against COVID-19 improved, compared with their immunosuppressed counterparts who didn’t get a booster, with a 58% lower risk of infection after adjustment for age, gender, race, and Charlson Comorbidity Index (adjusted HR, 0.42; 95% CI, 0.24-0.76; P = .0037). The study included nearly 4 months of data after the Centers for Disease Control and Prevention recommended a booster dose of the Moderna and Pfizer-BioNTech vaccines for immunocompromised individuals in August 2021. Among the immunosuppressed patients, 38.5% had received a booster dose.

There also was no apparent difference in the effectiveness between the Moderna and Pfizer-BioNTech vaccines, with adjusted hazard ratios showing 41%-48% lower risk of infection. Too few individuals in the study were vaccinated with the Johnson & Johnson vaccine to enable a sufficiently powered calculation of its effectiveness.

Other studies reach similar conclusions

The study findings fall into line with other studies of patient populations on immunosuppressants. A retrospective cohort study of Veterans Affairs patients with inflammatory bowel disease who were taking immunosuppressants, published in Gastroenterology, found that full vaccination with either Moderna and Pfizer-BioNTech vaccines was about 80% effective. Another retrospective cohort study of data from the National COVID Cohort Collaborative, published in JAMA Internal Medicine, reported that full vaccination significantly reduced the risk of COVID-19 breakthrough infection regardless of immune status. Immunosuppressed patients in this study had higher rates of breakthrough infections than immunocompetent patients, but the disparities were in line with what Dr. Zhao and the University of Michigan researchers reported.

A review of 23 studies of COVID-19 vaccinations, published in Lancet Global Health, found that immunocompromised people – 1,722 of whom were included in the studies – had lower rates of producing antibodies after two vaccine doses than did immunocompetent people, ranging from 27% to 92%, depending on the nature of their immunocompromised status, compared with 99% for the immunocompetent.
 

Strengths and limitations

One strength of the Michigan study is the quality of data, which were drawn from the Michigan Medicine electronic health record, Dr. Zhao said. “So, we know who received the vaccine and who didn’t. We also have access to data on patient health conditions, such as comorbidities, in addition to demographic variables (age, gender, and race), which were controlled in making fair comparisons between immunosuppressants and immunocompetent groups.”

Alfred Kim, MD, PhD, an assistant professor of internal medicine and rheumatology at Washington University in St. Louis, who was not involved with the study, credited Dr. Zhao and associates for delivering the first data that specifically quantified COVID-19 risk reduction in a large study population. Although he noted that the large sample size and the design reduced the chances of confounding and were strengths, he said in an interview that “lumping” the patients taking immunosuppressive drugs into one group was a weakness of the study.

“Clearly, there are certain medications (B-cell depleters, mycophenolate, for example) that carry the greatest risk of poor antibody responses post vaccination,” he said. “One would have to guess that the greatest risk of breakthrough infections continues to be in those patients taking these high-risk medications.”

Another possible problem, which the authors acknowledged, is spotty SARS-CoV-2 testing of study participants – “a systemic issue,” Dr. Kim noted.

“The easiest and most durable way to reduce the risk of getting COVID-19 is through vaccination, period,” he said. “Now we have infection-rates data from a real-world study cohort to prove this. Furthermore, boosting clearly provides additional benefit to this population.”

The National Institute of Allergy and Infectious Diseases provided funding for the study. Dr. Zhao, Dr. Zhao’s coauthors, and Kim disclosed no relevant financial relationships.

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

People taking immunosuppressive drugs benefit significantly from SARS-CoV-2 vaccines approved in the United States to prevent and reduce the severity of COVID-19, according to the first study to quantify the vaccines’ real-world effectiveness in this population.

Researchers’ analysis of the electronic medical records of more than 150,000 people in the University of Michigan’s health care system showed that even after becoming fully vaccinated, immunosuppressed individuals remain at higher risk for COVID-19 than are vaccinated people in the wider population who aren’t receiving immunosuppressive therapy. However, they still derive benefit from vaccination, particularly when bolstered with a booster dose.

BrianAJackson/Thinkstock

The study, published online in Annals of the Rheumatic Diseases, also claims to be the first to show that the Moderna (mRNA-1273) vaccine is as effective as the Pfizer-BioNTech (BNT162b2) vaccine for people taking immunosuppressants.

“Booster doses are effective and important for individuals on immunosuppressants,” corresponding author Lili Zhao, PhD, a research associate professor in biostatistics at the University of Michigan, Ann Arbor, said in an interview. “Previous studies focused mostly on the Pfizer vaccine, whereas our study is the first that also investigates the Moderna vaccine in a large, immunosuppressed population.”

The epidemiologic study included 154,519 fully vaccinated and unvaccinated adults in the Michigan Medicine electronic health record database. Participants were considered fully vaccinated if they were within 2 weeks of having received a second dose of the Pfizer-BioNTech and Moderna vaccines or the single-dose Johnson & Johnson (Ad26.COV2.S) vaccine. The study population included 5,536 immunosuppressed patients; of those, 4,283 were fully vaccinated, and 1,253 were unvaccinated.

The researchers focused on data collected from Jan. 1 to Dec. 7, 2021, so the study doesn’t cover the Omicron variant. “The conclusions for immunosuppressed individuals are likely to remain the same during the Omicron period,” Dr. Zhao said. “We are currently investigating this.” Johnson & Johnson paused production of its vaccine in February.

The researchers found that, among unvaccinated individuals, the immunosuppressed group had about a 40% higher risk of infection than did the immunocompetent patients (hazard ratio, 1.398; 95% confidence interval, 1.068-1.829; P = .0075) but a similar risk of COVID-19 hospitalization (HR, 0.951; 95% CI, 0.435-2.080; P = .9984). For the fully vaccinated, the gap was significantly wider: Immunosuppressed patients had more than double the risk of infection (HR, 2.173; 95% CI, 1.690-2.794; P < .0001) and almost five times the risk of hospitalization (HR, 4.861; 95% CI, 2.238-10.56; P < .0001), compared with immunocompetent patients.

However, among immunosuppressed individuals, the vaccinations significantly lowered risks, compared with not being vaccinated. There was a statistically significant 45% lower risk of infection (HR, 0.550; 95% CI, 0.387-0.781; P = .001) and similarly lower risk of hospitalization that did not reach statistical significance (HR, 0.534; 95% CI, 0.196-1.452; P = .3724).

When those immunosuppressed patients received a booster dose, their protection against COVID-19 improved, compared with their immunosuppressed counterparts who didn’t get a booster, with a 58% lower risk of infection after adjustment for age, gender, race, and Charlson Comorbidity Index (adjusted HR, 0.42; 95% CI, 0.24-0.76; P = .0037). The study included nearly 4 months of data after the Centers for Disease Control and Prevention recommended a booster dose of the Moderna and Pfizer-BioNTech vaccines for immunocompromised individuals in August 2021. Among the immunosuppressed patients, 38.5% had received a booster dose.

There also was no apparent difference in the effectiveness between the Moderna and Pfizer-BioNTech vaccines, with adjusted hazard ratios showing 41%-48% lower risk of infection. Too few individuals in the study were vaccinated with the Johnson & Johnson vaccine to enable a sufficiently powered calculation of its effectiveness.

Other studies reach similar conclusions

The study findings fall into line with other studies of patient populations on immunosuppressants. A retrospective cohort study of Veterans Affairs patients with inflammatory bowel disease who were taking immunosuppressants, published in Gastroenterology, found that full vaccination with either Moderna and Pfizer-BioNTech vaccines was about 80% effective. Another retrospective cohort study of data from the National COVID Cohort Collaborative, published in JAMA Internal Medicine, reported that full vaccination significantly reduced the risk of COVID-19 breakthrough infection regardless of immune status. Immunosuppressed patients in this study had higher rates of breakthrough infections than immunocompetent patients, but the disparities were in line with what Dr. Zhao and the University of Michigan researchers reported.

A review of 23 studies of COVID-19 vaccinations, published in Lancet Global Health, found that immunocompromised people – 1,722 of whom were included in the studies – had lower rates of producing antibodies after two vaccine doses than did immunocompetent people, ranging from 27% to 92%, depending on the nature of their immunocompromised status, compared with 99% for the immunocompetent.
 

Strengths and limitations

One strength of the Michigan study is the quality of data, which were drawn from the Michigan Medicine electronic health record, Dr. Zhao said. “So, we know who received the vaccine and who didn’t. We also have access to data on patient health conditions, such as comorbidities, in addition to demographic variables (age, gender, and race), which were controlled in making fair comparisons between immunosuppressants and immunocompetent groups.”

Alfred Kim, MD, PhD, an assistant professor of internal medicine and rheumatology at Washington University in St. Louis, who was not involved with the study, credited Dr. Zhao and associates for delivering the first data that specifically quantified COVID-19 risk reduction in a large study population. Although he noted that the large sample size and the design reduced the chances of confounding and were strengths, he said in an interview that “lumping” the patients taking immunosuppressive drugs into one group was a weakness of the study.

“Clearly, there are certain medications (B-cell depleters, mycophenolate, for example) that carry the greatest risk of poor antibody responses post vaccination,” he said. “One would have to guess that the greatest risk of breakthrough infections continues to be in those patients taking these high-risk medications.”

Another possible problem, which the authors acknowledged, is spotty SARS-CoV-2 testing of study participants – “a systemic issue,” Dr. Kim noted.

“The easiest and most durable way to reduce the risk of getting COVID-19 is through vaccination, period,” he said. “Now we have infection-rates data from a real-world study cohort to prove this. Furthermore, boosting clearly provides additional benefit to this population.”

The National Institute of Allergy and Infectious Diseases provided funding for the study. Dr. Zhao, Dr. Zhao’s coauthors, and Kim disclosed no relevant financial relationships.

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

There’s mixed news from Pfizer on results from their CLOVER trial (CLOstridium difficile Vaccine Efficacy TRial), a phase 3 study involving 17,500 adults aged 50 and older that evaluated their candidate vaccine (PF-06425090) against Clostridioides difficile (C. diff) for the prevention of C. diff. infection (CDI).

The bad news is that the trial didn’t meet its efficacy endpoint – the prevention of primary CDI. According to a Pfizer press release, “Vaccine efficacy under the primary endpoint was 31% (96.4%, confidence interval -38.7, 66.6) following the third dose and 28.6% (96.4%, CI -28.4, 61.0) following the second dose. For all CDI cases recorded at 14 days post dose 3, vaccine efficacy was 49%, 47%, and 31% up to 12 months, 24 months, and at final analysis, respectively.”

gaetan stoffel/gettyimages

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

There’s mixed news from Pfizer on results from their CLOVER trial (CLOstridium difficile Vaccine Efficacy TRial), a phase 3 study involving 17,500 adults aged 50 and older that evaluated their candidate vaccine (PF-06425090) against Clostridioides difficile (C. diff) for the prevention of C. diff. infection (CDI).

The bad news is that the trial didn’t meet its efficacy endpoint – the prevention of primary CDI. According to a Pfizer press release, “Vaccine efficacy under the primary endpoint was 31% (96.4%, confidence interval -38.7, 66.6) following the third dose and 28.6% (96.4%, CI -28.4, 61.0) following the second dose. For all CDI cases recorded at 14 days post dose 3, vaccine efficacy was 49%, 47%, and 31% up to 12 months, 24 months, and at final analysis, respectively.”

gaetan stoffel/gettyimages

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

There’s mixed news from Pfizer on results from their CLOVER trial (CLOstridium difficile Vaccine Efficacy TRial), a phase 3 study involving 17,500 adults aged 50 and older that evaluated their candidate vaccine (PF-06425090) against Clostridioides difficile (C. diff) for the prevention of C. diff. infection (CDI).

The bad news is that the trial didn’t meet its efficacy endpoint – the prevention of primary CDI. According to a Pfizer press release, “Vaccine efficacy under the primary endpoint was 31% (96.4%, confidence interval -38.7, 66.6) following the third dose and 28.6% (96.4%, CI -28.4, 61.0) following the second dose. For all CDI cases recorded at 14 days post dose 3, vaccine efficacy was 49%, 47%, and 31% up to 12 months, 24 months, and at final analysis, respectively.”

gaetan stoffel/gettyimages

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

The currently available two-dose COVID-19 vaccines were not effective in preventing symptomatic disease caused by the Omicron variant, as determined on the basis of data from more than 800,000 Omicron-infected individuals.

Early laboratory data suggested a substantially lower neutralizing antibody response to the Omicron variant, compared with both the original COVID-19 strain and the Delta variant, write Nick Andrews, PhD, of the United Kingdom Health Security Agency, London, and colleagues.

Vaccines have shown high levels of effectiveness against symptomatic disease and severe disease and death resulting from the original COVID-19 virus and the Alpha variant and modest effectiveness against the Beta and Delta variants, they say.

“Neutralizing antibodies correlate with protection against reinfection and vaccine effectiveness against infection; therefore, reduced vaccine effectiveness against the omicron variant is anticipated on the basis of these early laboratory findings,” they explain.

In a study published in the New England Journal of Medicine, the researchers identified 886,774 adults aged 18 years and older who had been infected with the Omicron variant, 204,154 who had been infected with the Delta variant, and 1,572,621 symptomatic control patients who tested negative for COVID-19 between Nov. 27, 2021, and Jan. 12, 2022. The participants had been vaccinated with two doses of BNT162b2 (Pfizer–BioNTech), ChAdOx1 nCoV-19 (AstraZeneca), or mRNA-1273 (Moderna) vaccine, plus a booster given at least 175 days after a second dose, after Sept. 13, 2021.

Vaccine effectiveness was calculated after primary immunization at weeks 2-4, 5-9, 10-14, 15-19, 20-24, and 25 or longer after the second dose, and at 2-4, 5-9, and 10 or more weeks after boosters.

Omicron infections that occurred starting 14 or more days after a booster occurred a median of 39 days after the booster.

“Vaccine effectiveness was lower for the Omicron variant than for the Delta variant at all intervals after vaccination and for all combinations of primary courses and booster doses investigated,” the researchers write.

Individuals who received two doses of ChAdOx1 nCoV-19 had almost no protection against symptomatic disease caused by Omicron from 20-24 weeks after the second dose. For individuals who received two doses of BNT162b2, effectiveness was 65.5% 2-4 weeks after the second dose, but effectiveness declined to 15.4% after 15-19 weeks and to 8.8% after 25 or more weeks. For individuals who received two doses of mRNA-1273, vaccine effectiveness was 75.1% after 2-4 weeks, but effectiveness declined to 14.9% after 25 or more weeks.

Boosters created a short-term improvement in vaccine effectiveness against the Omicron variant, but this effect also declined over time.

Among individuals who received primary doses of ChAdOx1 nCoV-19, vaccine effectiveness increased to 62.4% 2-4 weeks after a BNT162b2 booster, then declined to 39.6% after 10 or more weeks. After an mRNA-1273 booster, vaccine effectiveness increased to 70.1% at 2-4 weeks and decreased to 60.9% at 5-9 weeks.

Among individuals who received primary doses of BNT162b2, vaccine effectiveness increased to 67.2% 2-4 weeks after a BNT162b2 booster, then declined to 45.7% at 10 or more weeks. After an mRNA-1273 booster, vaccine effectiveness increased to 73.9% at 2-4 weeks, then declined to 64.4% at 5-9 weeks.

Among individuals who received primary doses of mRNA-1273, vaccine effectiveness increased to 64.9% 2-4 weeks after a BNT162b2 booster and 66.3% 2-4 weeks after an mRNA-1273 booster.

The study findings were limited by potential confounding from study participants who had traveled and may have had different levels of vaccine coverage and by the inability to break down estimates on the basis of age and clinical risk that might affect vaccine effectiveness, the researchers note. Other limitations include a lack of data on vaccine effectiveness for a longer period after boosters, they say.

However, the results are consistent with neutralization data for the Omicron variant in studies from the United Kingdom, South Africa, and Germany, they write. “Our findings support maximizing coverage with third doses of vaccine in highly vaccinated populations such as in the United Kingdom. Further follow-up will be needed to assess protection against severe disease and the duration of protection after booster vaccination,” they conclude.
 

Focus on severe disease prevention

Paul Offit, MD, of the University of Pennsylvania, Philadelphia, addressed the topic of vaccine effectiveness in an op-ed published on March 4 in The Philadelphia Inquirer. The following is adapted from the op-ed, with his permission.

“The goal of the COVID vaccine – as is true for all vaccines – is to prevent serious illness,” Dr. Offit wrote.

“For most people with normal immune systems, two doses of mRNA vaccines appear to do exactly that. But not everyone,” wrote Dr. Offit, who serves as director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and also serves on the Food and Drug Administration’s Vaccine Advisory Committee. “Three doses are required to induce high levels of protection against serious illness for people over 65 years of age or for people with other conditions that make them vulnerable, which can be anything from being overweight to having cancer. For people who are immune compromised, four doses might be required,” he noted.

Frequent vaccine boosting, although it may help prevent milder cases of COVID-19, such as those seen with the Omicron variant, is impractical, Dr. Offit emphasized. Instead, a newer, variant-specific vaccine might be needed if a variant emerges that overrides the protection against severe disease currently afforded by the available vaccines, he said. “But we’re not there yet. For now, we are going to have to realize that it is virtually impossible to prevent mild COVID without frequent boosting. So, let’s learn to accept that the goal of COVID vaccines is to prevent severe and not mild illness and stop talking about frequent boosting. Otherwise, we will never be able to live our lives as before,” he wrote.

The study was supported by the U.K. Health Security Agency. The researchers and Dr. Offit have disclosed no relevant financial relationships.

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

The currently available two-dose COVID-19 vaccines were not effective in preventing symptomatic disease caused by the Omicron variant, as determined on the basis of data from more than 800,000 Omicron-infected individuals.

Early laboratory data suggested a substantially lower neutralizing antibody response to the Omicron variant, compared with both the original COVID-19 strain and the Delta variant, write Nick Andrews, PhD, of the United Kingdom Health Security Agency, London, and colleagues.

Vaccines have shown high levels of effectiveness against symptomatic disease and severe disease and death resulting from the original COVID-19 virus and the Alpha variant and modest effectiveness against the Beta and Delta variants, they say.

“Neutralizing antibodies correlate with protection against reinfection and vaccine effectiveness against infection; therefore, reduced vaccine effectiveness against the omicron variant is anticipated on the basis of these early laboratory findings,” they explain.

In a study published in the New England Journal of Medicine, the researchers identified 886,774 adults aged 18 years and older who had been infected with the Omicron variant, 204,154 who had been infected with the Delta variant, and 1,572,621 symptomatic control patients who tested negative for COVID-19 between Nov. 27, 2021, and Jan. 12, 2022. The participants had been vaccinated with two doses of BNT162b2 (Pfizer–BioNTech), ChAdOx1 nCoV-19 (AstraZeneca), or mRNA-1273 (Moderna) vaccine, plus a booster given at least 175 days after a second dose, after Sept. 13, 2021.

Vaccine effectiveness was calculated after primary immunization at weeks 2-4, 5-9, 10-14, 15-19, 20-24, and 25 or longer after the second dose, and at 2-4, 5-9, and 10 or more weeks after boosters.

Omicron infections that occurred starting 14 or more days after a booster occurred a median of 39 days after the booster.

“Vaccine effectiveness was lower for the Omicron variant than for the Delta variant at all intervals after vaccination and for all combinations of primary courses and booster doses investigated,” the researchers write.

Individuals who received two doses of ChAdOx1 nCoV-19 had almost no protection against symptomatic disease caused by Omicron from 20-24 weeks after the second dose. For individuals who received two doses of BNT162b2, effectiveness was 65.5% 2-4 weeks after the second dose, but effectiveness declined to 15.4% after 15-19 weeks and to 8.8% after 25 or more weeks. For individuals who received two doses of mRNA-1273, vaccine effectiveness was 75.1% after 2-4 weeks, but effectiveness declined to 14.9% after 25 or more weeks.

Boosters created a short-term improvement in vaccine effectiveness against the Omicron variant, but this effect also declined over time.

Among individuals who received primary doses of ChAdOx1 nCoV-19, vaccine effectiveness increased to 62.4% 2-4 weeks after a BNT162b2 booster, then declined to 39.6% after 10 or more weeks. After an mRNA-1273 booster, vaccine effectiveness increased to 70.1% at 2-4 weeks and decreased to 60.9% at 5-9 weeks.

Among individuals who received primary doses of BNT162b2, vaccine effectiveness increased to 67.2% 2-4 weeks after a BNT162b2 booster, then declined to 45.7% at 10 or more weeks. After an mRNA-1273 booster, vaccine effectiveness increased to 73.9% at 2-4 weeks, then declined to 64.4% at 5-9 weeks.

Among individuals who received primary doses of mRNA-1273, vaccine effectiveness increased to 64.9% 2-4 weeks after a BNT162b2 booster and 66.3% 2-4 weeks after an mRNA-1273 booster.

The study findings were limited by potential confounding from study participants who had traveled and may have had different levels of vaccine coverage and by the inability to break down estimates on the basis of age and clinical risk that might affect vaccine effectiveness, the researchers note. Other limitations include a lack of data on vaccine effectiveness for a longer period after boosters, they say.

However, the results are consistent with neutralization data for the Omicron variant in studies from the United Kingdom, South Africa, and Germany, they write. “Our findings support maximizing coverage with third doses of vaccine in highly vaccinated populations such as in the United Kingdom. Further follow-up will be needed to assess protection against severe disease and the duration of protection after booster vaccination,” they conclude.
 

Focus on severe disease prevention

Paul Offit, MD, of the University of Pennsylvania, Philadelphia, addressed the topic of vaccine effectiveness in an op-ed published on March 4 in The Philadelphia Inquirer. The following is adapted from the op-ed, with his permission.

“The goal of the COVID vaccine – as is true for all vaccines – is to prevent serious illness,” Dr. Offit wrote.

“For most people with normal immune systems, two doses of mRNA vaccines appear to do exactly that. But not everyone,” wrote Dr. Offit, who serves as director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and also serves on the Food and Drug Administration’s Vaccine Advisory Committee. “Three doses are required to induce high levels of protection against serious illness for people over 65 years of age or for people with other conditions that make them vulnerable, which can be anything from being overweight to having cancer. For people who are immune compromised, four doses might be required,” he noted.

Frequent vaccine boosting, although it may help prevent milder cases of COVID-19, such as those seen with the Omicron variant, is impractical, Dr. Offit emphasized. Instead, a newer, variant-specific vaccine might be needed if a variant emerges that overrides the protection against severe disease currently afforded by the available vaccines, he said. “But we’re not there yet. For now, we are going to have to realize that it is virtually impossible to prevent mild COVID without frequent boosting. So, let’s learn to accept that the goal of COVID vaccines is to prevent severe and not mild illness and stop talking about frequent boosting. Otherwise, we will never be able to live our lives as before,” he wrote.

The study was supported by the U.K. Health Security Agency. The researchers and Dr. Offit have disclosed no relevant financial relationships.

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

The currently available two-dose COVID-19 vaccines were not effective in preventing symptomatic disease caused by the Omicron variant, as determined on the basis of data from more than 800,000 Omicron-infected individuals.

Early laboratory data suggested a substantially lower neutralizing antibody response to the Omicron variant, compared with both the original COVID-19 strain and the Delta variant, write Nick Andrews, PhD, of the United Kingdom Health Security Agency, London, and colleagues.

Vaccines have shown high levels of effectiveness against symptomatic disease and severe disease and death resulting from the original COVID-19 virus and the Alpha variant and modest effectiveness against the Beta and Delta variants, they say.

“Neutralizing antibodies correlate with protection against reinfection and vaccine effectiveness against infection; therefore, reduced vaccine effectiveness against the omicron variant is anticipated on the basis of these early laboratory findings,” they explain.

In a study published in the New England Journal of Medicine, the researchers identified 886,774 adults aged 18 years and older who had been infected with the Omicron variant, 204,154 who had been infected with the Delta variant, and 1,572,621 symptomatic control patients who tested negative for COVID-19 between Nov. 27, 2021, and Jan. 12, 2022. The participants had been vaccinated with two doses of BNT162b2 (Pfizer–BioNTech), ChAdOx1 nCoV-19 (AstraZeneca), or mRNA-1273 (Moderna) vaccine, plus a booster given at least 175 days after a second dose, after Sept. 13, 2021.

Vaccine effectiveness was calculated after primary immunization at weeks 2-4, 5-9, 10-14, 15-19, 20-24, and 25 or longer after the second dose, and at 2-4, 5-9, and 10 or more weeks after boosters.

Omicron infections that occurred starting 14 or more days after a booster occurred a median of 39 days after the booster.

“Vaccine effectiveness was lower for the Omicron variant than for the Delta variant at all intervals after vaccination and for all combinations of primary courses and booster doses investigated,” the researchers write.

Individuals who received two doses of ChAdOx1 nCoV-19 had almost no protection against symptomatic disease caused by Omicron from 20-24 weeks after the second dose. For individuals who received two doses of BNT162b2, effectiveness was 65.5% 2-4 weeks after the second dose, but effectiveness declined to 15.4% after 15-19 weeks and to 8.8% after 25 or more weeks. For individuals who received two doses of mRNA-1273, vaccine effectiveness was 75.1% after 2-4 weeks, but effectiveness declined to 14.9% after 25 or more weeks.

Boosters created a short-term improvement in vaccine effectiveness against the Omicron variant, but this effect also declined over time.

Among individuals who received primary doses of ChAdOx1 nCoV-19, vaccine effectiveness increased to 62.4% 2-4 weeks after a BNT162b2 booster, then declined to 39.6% after 10 or more weeks. After an mRNA-1273 booster, vaccine effectiveness increased to 70.1% at 2-4 weeks and decreased to 60.9% at 5-9 weeks.

Among individuals who received primary doses of BNT162b2, vaccine effectiveness increased to 67.2% 2-4 weeks after a BNT162b2 booster, then declined to 45.7% at 10 or more weeks. After an mRNA-1273 booster, vaccine effectiveness increased to 73.9% at 2-4 weeks, then declined to 64.4% at 5-9 weeks.

Among individuals who received primary doses of mRNA-1273, vaccine effectiveness increased to 64.9% 2-4 weeks after a BNT162b2 booster and 66.3% 2-4 weeks after an mRNA-1273 booster.

The study findings were limited by potential confounding from study participants who had traveled and may have had different levels of vaccine coverage and by the inability to break down estimates on the basis of age and clinical risk that might affect vaccine effectiveness, the researchers note. Other limitations include a lack of data on vaccine effectiveness for a longer period after boosters, they say.

However, the results are consistent with neutralization data for the Omicron variant in studies from the United Kingdom, South Africa, and Germany, they write. “Our findings support maximizing coverage with third doses of vaccine in highly vaccinated populations such as in the United Kingdom. Further follow-up will be needed to assess protection against severe disease and the duration of protection after booster vaccination,” they conclude.
 

Focus on severe disease prevention

Paul Offit, MD, of the University of Pennsylvania, Philadelphia, addressed the topic of vaccine effectiveness in an op-ed published on March 4 in The Philadelphia Inquirer. The following is adapted from the op-ed, with his permission.

“The goal of the COVID vaccine – as is true for all vaccines – is to prevent serious illness,” Dr. Offit wrote.

“For most people with normal immune systems, two doses of mRNA vaccines appear to do exactly that. But not everyone,” wrote Dr. Offit, who serves as director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and also serves on the Food and Drug Administration’s Vaccine Advisory Committee. “Three doses are required to induce high levels of protection against serious illness for people over 65 years of age or for people with other conditions that make them vulnerable, which can be anything from being overweight to having cancer. For people who are immune compromised, four doses might be required,” he noted.

Frequent vaccine boosting, although it may help prevent milder cases of COVID-19, such as those seen with the Omicron variant, is impractical, Dr. Offit emphasized. Instead, a newer, variant-specific vaccine might be needed if a variant emerges that overrides the protection against severe disease currently afforded by the available vaccines, he said. “But we’re not there yet. For now, we are going to have to realize that it is virtually impossible to prevent mild COVID without frequent boosting. So, let’s learn to accept that the goal of COVID vaccines is to prevent severe and not mild illness and stop talking about frequent boosting. Otherwise, we will never be able to live our lives as before,” he wrote.

The study was supported by the U.K. Health Security Agency. The researchers and Dr. Offit have disclosed no relevant financial relationships.

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