Moderna Argues to FDA for Half-Dose of Vaccine as Booster

In documents released Tuesday morning, Moderna argued that the Food and Drug Administration should authorize a half-dose of its coronavirus vaccine as a booster shot for recipients at least six months after the second dose, citing evidence that the vaccine’s potency against infection wanes over time. The agency noted in its own analysis that, overall, available data show Moderna and the other vaccines “still afford protection against severe Covid-19 disease and death in the United States.” Moderna cited the rate of breakthrough infections, “real world evidence of reduced effectiveness against the Delta variant,” and falling levels of neutralizing antibodies from its vaccine six to eight months after a second dose. The company said its clinical trial studies showed that a third injection boosted antibody levels — one measure of the immune system’s response — higher than what they had been before the second dose.