The Food and Drug Administration set the stage Tuesday for a new round of decisions on which Americans should get coronavirus booster shots, releasing a review of data suggesting that an additional half-dose of Moderna’s vaccine at least six months after the second dose increased antibody levels. But the agency did not take a position on whether an additional shot was necessary.
An independent advisory panel of experts will examine the available data on both Moderna and Johnson & Johnson boosters in a two-day meeting later this week. Votes are scheduled on whether to recommend emergency authorization of boosters for both vaccines. While the panel’s votes are not binding, the F.D.A. typically follows them.
In documents released Tuesday, Moderna argued that a third injection is needed because the potency of its vaccine wanes over time, with levels of neutralizing antibodies falling six to eight months after a second dose. The company also cited “real world evidence of reduced effectiveness against the Delta variant,” although the F.D.A. noted that the studies diverge on whether Moderna’s protection weakened over time against symptomatic infection or against the Delta variant.
The company did not argue that a booster was necessary to prevent severe disease or hospitalization, but concentrated its arguments on preventing infection and mild to moderate disease.
Moderna said the mean antibody level of participants in its study was 1.8 times higher after the booster than it was after the second shot. In another measurement, the booster raised neutralizing antibodies at least fourfold in 87.9 percent of people compared to after the second dose, thus narrowly failing to meet the agency’s requirement of 88.4 percent.
In a document that Johnson & Johnson submitted to the F.D.A. ahead of this week’s meeting, the company argued that booster shots of its vaccine increased protection against Covid-19, including against severe forms of the disease, and increased the strength of the body’s immune response against virus variants. Johnson & Johnson said that a booster shot could be administered as early as two months after the first dose, but recommended doing so at least six months after, when it said recipients had been shown to have a more robust immune response.
Noah Weiland contributed reporting.
Source: The New York Times