Johnson & Johnson recommends booster shot

A second dose of the J&J/Janssen COVID-19 vaccine can be 94 percent effective against symptomatic infection, the company reported Tuesday. A booster administered six months after the first dose showed a 12-fold increase in antibodies, according to data from a late-stage clinical trial. The data has not been published in a journal or peer-reviewed yet, but the company sent it to the U.S. Food and Drug Administration and the European Medicines Agency for review and possible approval.

What do the numbers mean? J&J is basing its recommendation on a trial involving 32,000 adult participants in 10 countries, including the United States. The booster shot showed 75 percent protection against severe infection, with 94 percent effectiveness for U.S. participants. J&J did not say why the rates are different, but it might be due to different variants circulating in other countries.

Dig deeper: Read John Dawson’s report in Beginnings about J&J vaccine side effects.