FDA vaccine regulators argue against Covid-19 vaccine boosters in new international review

A group of international experts — including, notably, two outgoing Food and Drug Administration vaccine regulators — argues in a new paper against offering Covid-19 vaccine boosters to the general population.

The paper, published Monday in the Lancet, is based on a review of available data about the durability of vaccine protection. That it was co-authored by Marion Gruber and Phil Krause, two veteran FDA officials who have been leading the agency’s review of Covid-19 vaccine applications, amounts to a strikingly direct rebuff to the Biden administration as it lays plans for booster shots. Gruber and Krause announced last month they would be leaving the agency this fall.

Others authors include experts from the World Health Organization, which has called for countries to delay broad booster plans as many countries are still suffering from a lack of vaccine supply in the face of horrific outbreaks driven by the highly transmissible Delta variant.

“Current evidence does not, therefore, appear to show a need for boosting in the general population, in which efficacy against severe disease remains high,” the authors wrote.

The paper is sure to add to debate about whether the White House got ahead of its scientific agencies in outlining plans for general boosters, which the Biden administration had signaled would start rolling out next Monday. Experts broadly agree that people with compromised immune systems should be receiving third shots of the mRNA vaccines from Pfizer-BioNTech and Moderna, which were authorized as two-dose courses. And some experts argue that seniors, who generally mount less robust immune responses to vaccines, should also be eligible for boosters.

But for the general population, experts have been divided over whether boosters are necessary. Some argue that a third shot (or, in the case of Johnson & Johnson’s vaccine, a second shot) should really be considered part of the initial dosing plan, while others say there is no evidence that the vaccines are losing any strength at protecting people from hospitalization or death from Covid-19 — the worst outcomes that the shots were primarily designed to guard against.

“Even if boosting were eventually shown to decrease the medium-term risk of serious disease, current vaccines supplies could save more lives if used in previously unvaccinated populations than if used as boosters in vaccinated populations,” the paper states.

The authors acknowledge that boosting could eventually be needed for the general population if immunity wanes or a variant emerges that significantly undercuts the vaccines’ power. They also point to data showing that the Delta variant is leading to more symptomatic breakthrough infections than other variants. But they add that “the message that boosting might soon be needed, if not justified by robust data and analysis, could adversely affect confidence in vaccines and undermine messaging about the value of primary vaccination.”

Pointing to the possibility of side effects from boosters doses, the authors write that “if unnecessary boosting causes significant adverse reactions, there could be implications for vaccine acceptance that go beyond Covid-19 vaccines.”

The FDA, meanwhile, is convening its vaccine advisory committee for a public meeting Friday to discuss Pfizer’s application for Covid-19 vaccine boosters, at which the topic of whether boosters are necessary is sure to come up.