The Food and Drug Administration on Wednesday released much of the evidence for its advisory committee to review. The agency took a decidedly neutral tone on the rationale for boosters – an unusual and cautious approach that is all the more striking after President Joe Biden and his top health advisers trumpeted a recall campaign they hoped to begin next week.
Pfizer’s argument: While protection against serious illness remains in the United States, immunity to milder infections declines about six to eight months after the second dose. The company gave an additional dose to 306 people at that time and recorded levels of anti-virus antibodies three times higher than after previous injections.
More importantly, Pfizer said, these antibodies appear potent enough to handle the extra-contagious delta variant that is emerging nationwide.
To back up its case, Pfizer reported data to the FDA from Israel, which began offering boosters over the summer.
This study followed about 1 million people aged 60 and over and found that those who received an additional injection were much less likely to be infected soon after. Pfizer said this translates to “about 95% effectiveness” as the delta spread, comparable to the protection seen shortly after the vaccine rolled out earlier in the year.
Israeli data, also published in the New England Journal of Medicine on Wednesday, cannot say how long the enhanced protection lasts.
FDA reviewers, however, suggested they would focus primarily on research on how vaccines work in Americans, saying that “may most accurately represent vaccine effectiveness in the American population.”
Overall, the data shows that the Pfizer vaccine and other COVID-19 vaccines licensed in the United States “still provide protection against severe COVID-19 illness and death in the United States,” the United States said. agency, summarizing the evidence.
The FDA is not required to follow the advice of its independent advisory committee. But if the agency cancels its own experts, it could fuel public confusion. Earlier this week, two leading FDA vaccine regulators joined a group of international scientists to now reject recalls for otherwise healthy people, citing continued strong protection against serious illness.
Dr Anna Durbin of the Johns Hopkins School of Public Health said it’s important to understand that the FDA’s decision is simply whether an extra dose is safe and does what it promises – boosting levels of immunity.
If the FDA decides that the extra dose does both of these things, then the Centers for Disease Control and Prevention will have to decide who should get another dose. The CDC has scheduled a meeting of its own advisers for next week and said it is considering a recall for certain people – such as the elderly, nursing home residents and frontline health workers – instead. than the general population.
The larger problem: “What’s really going to control the delta variant is vaccinating the unvaccinated, not the boosters,” Durbin said. More than a third of Americans eligible for vaccines are not yet fully vaccinated, according to CDC data.
The United States is already offering an extra dose of Pfizer or Moderna vaccines for people with severely weakened immune systems.
For the average person, what is the evidence that immunity is waning? The CDC says real-world data shows protection against serious illness, hospitalizations and death is holding up. But in a recent study, protection from infection declined when the delta variant hit: it was 91% in the spring but 78% in June and July. The CDC also saw a clue that for people 75 and older, protection against hospitalizations declined slightly in the summer.
Moderna has also asked the FDA to authorize a booster dose of its vaccine and released its own study on declining immunity on Wednesday.
The researchers compared about 14,000 people in Moderna’s 2020 vaccine study who received a first dose about a year ago with 11,000 others who were vaccinated last winter, about eight months ago. As the delta increased in July and August, Moderna concluded that the most recently vaccinated group had a 36% lower rate of “breakthrough” infections compared to those vaccinated longer ago.
It is not known how soon the FDA will consider a Moderna recall, or one for people who have received the single injection Johnson & Johnson vaccine.
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