Moderna's vaccine may prevent some asymptomatic infections after first shot

The vaccine maker said in briefing documents it submitted to the US FDA released on Tuesday that it had not yet completed its full analysis on the efficacy against asymptomatic infections

Moderna Inc said data from the late stage trial of its Covid-19 vaccine suggests that it could prevent some asymptomatic infections as soon as the first dose of the shot is given.

The vaccine maker said in briefing documents it submitted to the US Food and Drug Administration released on Tuesday that it had not yet completed its full analysis on the efficacy against asymptomatic infection.

Still, it said that 38 trial participants in the placebo arm of its trial tested positive for Covid-19 without exhibiting symptoms at the time of their second dose. That was nearly triple the number in the vaccine arm of the trial, where there were 14 positive tests from asymptomatic people.