FDA's Vaccines and Related Biological Products Advisory Committee (VRBPAC) on Thursday voted 19-0 to endorse booster shots of Moderna's Covid-19 vaccine for certain populations, setting the stage for FDA to authorize the booster shots.

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Advisory panel votes to recommend booster shots of Moderna's vaccine

The panel voted to recommend the booster shot to those ages 65 and older, adults with underlying health conditions that put them at increased risk of severe Covid-19, and those at high risk of exposure to the coronavirus because of their occupation or because they live in an institution such as a prison or a homeless shelter.

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The panel also recommended that booster shots be half the dose of the first two shots and be given at least six months after the second shot.

At the meeting, Moderna presented the results of a trial of 171 people who received a half-dose booster of its vaccine after receiving the standard, two-dose regimen. According to the trial, around 87.9% of people who received a booster saw at least a four-fold increase in neutralizing antibodies.

Members of the panel criticized Moderna for not presenting more complete data.

Patrick Moore, a professor at the University of Pittsburgh Cancer Institute, said he had "real issues" with the vote based on questions he had about Moderna's data, but said the vote was "more gut feeling rather than based on really truly serious data."

"The data itself is not strong, but it is certainly going in a direction that is supportive of this," Moore added.

Paul Offit, director of the Vaccine Education Center at the Children's Hospital of Philadelphia, criticized the idea that an increase in mild or asymptomatic Covid-19 cases is a sufficient reason to provide booster shots.

"If the goal is to try and protect against the unfortunately-named breakthrough infections of asymptomatic infection ... then we're going to be talking about getting frequent boosters, which I don't think is a reasonable strategy for this," he said.

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Stanley Perlman, a microbiologist from the University of Iowa, said that while he has concerns, he supports an emergency use authorization (EUA) for a Moderna booster shot "because we've already approved it for Pfizer, and I don't see how we can possibly not approve it for Moderna and not have most U.S. folks completely confused. I think it's a pragmatic issue."

Next steps

On Friday, VRBPAC will meet to discuss whether to recommend a booster shot of Johnson & Johnson's (J&J) vaccine. Following that, FDA could issue an EUA for Moderna's and J&J's booster shots. While the agency is not bound to follow VRBPAC's recommendations, it typically does.

Then, CDC will convene a panel of advisers to offer its own recommendations on who should receive boosters, with CDC Director Rochelle Walensky making the final call on the agency's recommendation.

In remarks Thursday, President Joe Biden said he expects a final decision from FDA and CDC regarding booster shots "in the next couple of weeks."

Biden also said FDA and CDC are working to determine whether to recommend Covid-19 vaccines to children ages five to 11 and should make that decision "in the next few weeks." (Kopp, Roll Call, 10/14; Herper/Branswell, STAT News, 10/14; Gardner et al., Politico, 10/14; Fernandez, Axios, 10/14; Walker, MedPage Today, 10/14; Anderson, Becker's Hospital Review, 10/14; Hensley, "Shots," NPR, 10/14; President Biden remarks, 10/14)