FDA Advisors Green Light For Pfizer Boosters For People 65+ And At Risk Groups

Enlarge / Vials with COVID-19 vaccine labels showing the logos of pharmaceutical company Pfizer and German biotech company BioNTech.

A committee of independent advisers from the Food and Drug Administration voted unanimously (18-0) to allow a booster dose of Pfizer / BioNTech COVID-19 vaccine for people aged 65 and over. more, as well as those at high risk based on an underlying medical condition and / or occupational exposure (eg, healthcare workers). It is recommended that the booster doses be given at least six months after the end of the two primary doses.

If the FDA goes ahead with the advisory committee’s recommendation, which it likely will, boosters will be offered to these two groups on the basis of an emergency use authorization.

Before voting for permission for both groups, the committee rejected the idea of ​​approving boosters for anyone aged 16 and over with a resounding 16-2 vote against.

Typically, the committee – the Advisory Committee on Vaccines and Related Biologics (VRBPAC) – felt that there was simply too little safety data to make an assessment, especially for young men. those most at risk of developing a rare side effect of the COVID-19 vaccine of inflammation in or around the heart (myocarditis and pericarditis). In addition, the committee considered that there was no convincing data indicating that overall vaccine protection against serious illness, hospitalization and death had diminished to the point that a booster was required.

“A third dose is probably good,” said Ofer Levy, VRBPAC voting member and infectious disease expert at Harvard, after voting against boosters for all. “This is already true for the immunocompromised. It is probably beneficial, in my opinion, for the elderly and could possibly be indicated for the general population. I just don’t think we are there yet in terms of the data. . “

The votes came after a tumultuous one-day meeting in which members of the advisory board appeared to resent the idea that they would give the green light to boosters for the general population. Last month, the Biden administration announced ahead of the FDA review that it was ready to roll out booster shots for those vaccinated starting the week of September 20. The announcement reportedly sparked frustration and anger within the regulatory agency, leading two high-ranking regulators to announce their resignations.

Vaccine efficacy

One of those resignations was Marian Gruber, the now-outgoing director of the FDA’s Office of Vaccine Research and Review. At the opening of today’s deliberations, she thanked her staff, noting that this was probably her last VRBPAC meeting. In her opening remarks, she stressed that the decision whether or not to approve a booster dose depends on determining its “safety”, which “involves determining whether its benefits outweigh its risks.” For younger men, this leaves the delicate question of whether the potentially increased risk of myocarditis / pericarditis would be outweighed by the potential benefits of a third dose, given that younger men are already at a lower risk of serious disease. than older groups and still seem to have high levels of protection against the two primary doses.

CDC epidemiologist Sara Oliver presented a summary of the data suggesting that the vaccine’s effectiveness against the infection declined over time, but the protection against hospitalizations remained strong. Comparing the efficacy of the pre-delta vaccine in adults aged 18 years and older with the latest post-delta data, the vaccine’s efficacy range against infection increased from 72 percent to 92 percent before the delta to a range 39 to 84 percent after delta in July. For hospitalization, vaccine efficacy before delta ranged from 84 to 97 percent, falling to a range of 75 to 95 percent in July after delta.

Critically, when the agency’s scans only looked at older populations rather than all adults together, the vaccine’s efficacy still appeared to be strong, with over 88% efficacy in the elderly. 75 years and over. However, Dr Oliver noted data from Qatar suggesting that protection from hospitalization decreased in people aged 60 and over after 25 weeks of vaccination, although the confidence intervals are extremely wide.

Likewise, Israeli experts have presented data suggesting that the vaccine’s effectiveness continues to decline over time, with older groups seeing less protection against serious illnesses. Israel is ahead of the United States by about three months to vaccinate a large part of its population. Thus, the country is considered as an indicator of the effectiveness of vaccines. In light of data suggesting a widespread decline in protection, Israel rolled out a booster on July 30 for all ages 16 and older, starting with the elderly. Since then, Israeli data suggests that the boosters have hampered confirmed cases in people over 60 and reduced the relative risk of severe illness in this age group by more than 10 times. Unfortunately, there hasn’t been enough time since the boosters were rolled out to young men to generate useful safety data that could inform a decision in the United States.

Data issues

In another presentation at the meeting, statistician Jonathan Sterne of the University of Bristol cautioned against making actual estimates of vaccine efficacy due to various confounding factors. These include different characteristics of people who get vaccinated versus those who don’t, as well as past COVID infections that offer some protection to the unvaccinated. Estimates of vaccine effectiveness can be influenced by the timing of people’s immunizations, the risk factors each group may have, the waves of infection, and how the waves are timed with vaccinations. Many of these factors could add up to make the vaccine appear to be less effective than it actually is. For example, people who were the first to receive a vaccine included those with weakened immune systems, so the increase in infections and serious illness could perhaps represent the problem of poor immune responses in these populations rather than a significant decline in overall protection.

Also, it’s important to note that Israel defines critical illness differently from the United States, counting people with high respiratory rates and blood oxygen levels below 94%. In the United States, studies often define serious illnesses as those requiring hospitalization or intensive care, or those that die as a result of their infection.

Pfizer presented its own case for the recalls, showing US data suggesting that protection against infection has waned but protection against hospitalization has not waned. The company argued that data from Israel portends a decline and suggests that the boosters will prevent increases in serious illness and death among those vaccinated.

Regarding safety, Pfizer and the FDA made separate presentations that chose Pfizer’s safety data, which only involved 306 people between the ages of 18 and 55. Data suggested that a third dose increased antibody levels to levels comparable if not greater than those seen after the second doses. Likewise, side effects from a third dose were similar to those seen after a second dose, with the most common effects being injection site pain, fatigue, headache, chills, and muscle pain.

Overall, the VRBPAC has been influenced by data from Israel suggesting that the elderly may soon become more vulnerable to serious illness, hospitalization and death and that booster doses may increase protection in any way. security. But with so little safety data on the younger groups and without a clear and growing risk of serious illness in these younger groups, members were not convinced that boosters should be offered to all 16-year-olds and more at present.

Final decisions

In their final deliberations, members addressed those aged 65 and over as well as those at high risk. The threshold and the definitions are fragile. The committee did not have decisive data on which age group to draw the line to, with some committee members suggesting those over 50 or 60. Ultimately, the FDA reworded the final voting question, which included the threshold of 65.

In addition, the committee considered it necessary to include those at high risk of serious illness due to underlying conditions, given the possibility of further decline and the need to protect health systems from ‘be overwhelmed. Who might be eligible under these conditions has yet to be defined by an advisory committee of the Centers for Disease Control and Prevention – the Advisory Committee on Immunization Practices – which is due to meet on September 22.

Likewise, VRBPAC felt it was important to include people at high risk of infection due to occupational exposure, as booster injections can reduce the risk of infection and transmission. . As hospitals across the country are strained and buckled under the weight of the delta coronavirus wave, the committee wanted to ensure that healthcare workers, frontline workers and teachers could benefit from it. maximum protection – again – to protect all health systems.

While today’s decision may disappoint some hoping for a general green light for boosters, the committee was happy to have followed the science and resisted any pressure from the Biden administration.

“I think this should demonstrate to the public that the members of this committee are independent from the FDA and that in fact we are making our voices heard,” Archana Chatterjee, Voting Member of VRBPAC and Dean of Chicago Medical School.

Going forward, VRBPAC Chairman Arnold Monto noted that if booster doses are allowed using an EUA, it will be easy to review the data in the near future to determine if and when booster shots are given. for larger groups may be needed.

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