Debate Continues on Broader Use of COVID-19 Boosters in United States

Pharmacists who began to prepare to issue COVID-19 booster shots later this month might want to take a breather. The issue continues to be contentious with an international journal commentary, including authors from the FDA, arguing that boosters are too much, too soon. Here is more information.

SILVER SPRING, MD – Just days before a Food and Drug Administration advisory group was scheduled to meet to discuss booster doses of COVID-19 vaccines, a group of international experts – including representatives from the FDA’s Office of Vaccines Research and Review published an opinion piece strongly recommending against them at this point.

“A new wave of COVID-19 cases caused by the highly transmissible delta variant is exacerbating the worldwide public health crisis, and has led to consideration of the potential need for, and optimal timing of, booster doses for vaccinated populations,” write Philip R Krause, MD, and Thomas R Fleming, PhD, of the FDA and colleagues. “Although the idea of further reducing the number of COVID-19 cases by enhancing immunity in vaccinated people is appealing, any decision to do so should be evidence-based and consider the benefits and risks for individuals and society.”

Their viewpoint piece, published in The Lancet, points out that COVID-19 vaccines continue to be effective against severe disease, even with the delta variant. As for potential use of boosters, the authors emphasize, “Careful and public scrutiny of the evolving data will be needed to assure that decisions about boosting are informed by reliable science more than by politics. Even if boosting were eventually shown to decrease the medium-term risk of serious disease, current vaccine supplies could save more lives if used in previously unvaccinated populations than if used as boosters in vaccinated populations.”

The FDA announced that its outside advisers would meet on Sept. 17 to discuss the use of a booster vaccine dose for the Pfizer-BioNTech vaccine. Boosters for the Moderna vaccine, which the manufacturer has suggested should be half strength, were planned for later discussion. With immunocompromised patients already eligible for booster doses, President Joe Biden earlier had announced an effort to extend the program to all vaccinated Americans by Sept. 20, pending scientific review.

The Lancet commentary doesn’t argue against the use of boosters in immunocompromised or similar vaccine recipients, however. The article notes that it might be “appropriate for some individuals in whom the primary vaccination, defined here as the original one-dose or two-dose series of each vaccine, might not have induced adequate protection—e.g., recipients of vaccines with low efficacy or those who are immunocompromised.”

The authors caution, however, that those who did not respond robustly to the primary vaccination might also not respond well to a booster. It also is not clear whether immunocompromised patients would be better off with an additional dose of the same vaccine or of a different vaccine that might spur the primary immune response, they add.

The commentators also concede that boosters “might ultimately be needed in the general population because of waning immunity to the primary vaccination or because variants expressing new antigens have evolved to the point at which immune responses to the original vaccine antigens no longer protect adequately against currently circulating viruses.”

On the other hand, they caution that, while the benefits of primary COVID-19 vaccination clearly outweigh the risks, the widespread introduction of boosters too soon or too frequently could increase immune-mediated side-effects, including myocarditis, which is more common after the second dose of some mRNA vaccines,3 or Guillain-Barre syndrome, which has been associated with adenovirus-vectored COVID-19 vaccines.

That, in turn, could lower vaccine acceptance for COVID-19 and other viruses, they add.

The analysis concludes that “any decisions about the need for boosting or timing of boosting should be based on careful analyses of adequately controlled clinical or epidemiological data, or both, indicating a persistent and meaningful reduction in severe disease, with a benefit-risk evaluation that considers the number of severe cases that boosting would be expected to prevent, along with evidence about whether a specific boosting regimen is likely to be safe and effective against currently circulating variants. As more information becomes available, it may first provide evidence that boosting is needed in some subpopulations. However, these high-stakes decisions should be based on peer-reviewed and publicly available data and robust international scientific discussion.”

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