Top FDA Officials Say Two Full Doses of COVID-19 Vaccines a Must

TUESDAY, Jan. 5, 2021 -- Two top officials at the U.S. Food and Drug Administration said Monday that any American who gets the Moderna or Pfizer COVID-19 vaccines must get two full doses, despite international debate on possible ways to stretch vaccine supply.

"We have been following the discussions and news reports about reducing the number of doses, extending the length of time between doses, changing the dose [half-dose], or mixing and matching vaccines in order to immunize more people against COVID-19," FDA Commissioner Stephen Hahn, M.D., and Peter Marks, M.D., Ph.D., who heads the FDA vaccine division, said in an agency statement. "These are all reasonable questions to consider and evaluate in clinical trials. However, at this time, suggesting changes to the FDA-authorized dosing or schedules of these vaccines is premature and not rooted solidly in the available evidence."

In the United Kingdom, where England and Scotland have entered a third national lockdown as officials battle a more contagious variant of the coronavirus, officials have said they will allow more than 21 days between doses of the Pfizer vaccine and would consider allowing people to get vaccinated with two different vaccines.

But Hahn and Marks rejected those policies for the United States.

"The available data continue to support the use of two specified doses of each authorized vaccine at specified intervals," they wrote, adding that it is understandable that people may want to stretch the vaccine supply, but it is not safe to do so. "If people do not truly know how protective a vaccine is, there is the potential for harm because they may assume that they are fully protected when they are not, and accordingly, alter their behavior to take unnecessary risks."

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Posted: January 2021