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People need both doses of COVID-19 vaccines, FDA says

The FDA says people who receive Moderna and Pfizer vaccines must get two full doses.

Music producer Emilio Estefan, 67, gives the thumbs-up while he receives the Pfizer-BioNTech COVID-19 vaccine at Jackson Memorial Hospital, Wednesday, Dec. 30, 2020, in Miami.
Music producer Emilio Estefan, 67, gives the thumbs-up while he receives the Pfizer-BioNTech COVID-19 vaccine at Jackson Memorial Hospital, Wednesday, Dec. 30, 2020, in Miami.
Lynne Sladky, Associated Press

Food and Drug Administration officials said Monday that anyone who receives the Moderna and Pfizer COVID-19 vaccines needs two full doses — not just one, or half of one.

What’s going on?

The FDA issued a statement about a recent idea to stretch the coronavirus vaccine supply by cutting doses in half, or offering one dose for everyone before giving second doses out to those who received the first dose.

FDA Commissioner Dr. Stephen Hahn and Dr. Peter Marks issued the following statement on the strategy idea:

“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. 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. Without appropriate data supporting such changes in vaccine administration, we run a significant risk of placing public health at risk, undermining the historic vaccination efforts to protect the population from COVID-19.”

The strategy comes after some data showed those who received a half dose of the COVID-19 vaccine were somewhat protected from the virus, according to CNN. The United Kingdom said it would likely embrace this idea, offering first doses for all before giving out second doses, especially as the new COVID-19 variant spreads throughout the area.

But Marks and Hahn downplayed this idea since there wasn’t enough research done on the subject.

“What we have seen is that the data in the firms’ submissions regarding the first dose is commonly being misinterpreted. In the phase 3 trials, 98% of participants in the Pfizer-BioNTech trial and 92% of participants in the Moderna trial received two doses of the vaccine at either a three- or four-week interval, respectively. Those participants who did not receive two vaccine doses at either a three-or four-week interval were generally only followed for a short period of time, such that we cannot conclude anything definitive about the depth or duration of protection after a single dose of vaccine from the single dose percentages reported by the companies.

“Using a single dose regimen and/or administering less than the dose studied in the clinical trials without understanding the nature of the depth and duration of protection that it provides is concerning, as there is some indication that the depth of the immune response is associated with the duration of protection provided. 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.”

What does Dr. Fauci think?

Dr. Anthony Fauci, the top federal infectious disease expert, said on NBC’s “Meet the Press” program over the weekend that the U.S. shouldn’t shift away from the strategy used in trials.

  • “We know what the science tells us,” Fauci said. “So my feeling ... is let’s do it the way the clinical trials have instructed us to do it. But let’s get more efficient into getting it into people’s arms.”