By Thomas M. Burton and Peter Loftus
A committee of independent medical experts convenes Friday to review Johnson & Johnson's Covid-19 single-dose vaccine, the final step before U.S. health regulators decide whether to authorize use of a third shot.
The panel, which includes 22 medical specialists in fields like internal medicine, pediatrics, vaccines and epidemiology, regularly advises the U.S. Food and Drug Administration about experimental vaccines. It voted to recommend shots from Pfizer Inc. and Moderna Inc. before the agency authorized them in December.
If the panel votes to endorse the J&J shot, the agency is expected to permit the product's wide use as soon as Saturday.
During the all-day public meeting, representatives from the FDA and J&J will discuss the safety and effectiveness of the company's vaccine in a 44,000-plus subject study, according to an agenda.
The vaccine was 66% effective at protecting people from moderate to severe Covid-19, an FDA review found, and even more effective at preventing severe disease alone.
The advisory committee also will delve into how effective the J&J vaccine is in preventing new cases caused by Covid-19 mutations and to what extent the shot might reduce asymptomatic spread of the coronavirus.
That issue of silent contagion is crucial, since the virus has largely been spread by people who were infected but didn't realize it because they had no symptoms.
J&J, citing preliminary evidence in an analysis released by the FDA, said the vaccine was 65.5% effective in preventing asymptomatic infections, in a subset of study subjects.
Rollout of the J&J vaccine doses could add -- by an estimated 20% during March -- to the total number available, as health authorities pick up the pace of vaccinations and try to inoculate enough people as quickly as possible so business, schools and other establishments can fully reopen.
J&J has said it would deliver about 20 million doses for U.S. use by the end of March.
The FDA often convenes public meetings of outside experts to scrutinize experimental drugs, devices and vaccines up for agency approval, in part to boost public acceptance of the products should they be cleared for wide use.
J&J's vaccine appeared to be safe in its pivotal study, the FDA found, aside from being effective.
The vaccine was less effective in South Africa, where a more-transmissible Covid-19 variant has thrived, than in the U.S. J&J is among the companies working on new shots targeting the new strain, which several current vaccines don't appear to work as well against.
J&J's Covid-19 shot was, however, very effective against severe and critical cases in South Africa. The vaccine was 73.1% effective in preventing such cases occurring at least 14 days after vaccination, and 81.7% effective in preventing such cases at least 28 days after vaccination.
Write to Thomas M. Burton at firstname.lastname@example.org and Peter Loftus at email@example.com
(END) Dow Jones Newswires