In its clinical study of about 44,000 patients in the U.S., South Africa and other countries, the agency said, there were seven Covid-19 deaths among patients getting a placebo, and none among those who got the vaccine.
The finding appears to bolster J&J’s earlier statements that the vaccine is very effective in preventing severe disease.
The federal agency’s analysis represents a key step toward a possible FDA authorization of the vaccine as early as this weekend, according to a person familiar with the matter.
A committee of outside medical specialists convenes Friday to evaluate the analyses by both the FDA and the company, as the panel did for the first two Covid-19 vaccines to be cleared for use.
The advisory committee is expected to recommend the FDA authorize the J&J vaccine, and the agency is expected to make its decision soon after.
The regulatory green light would bolster vaccination efforts just as health authorities pick up the pace to get people back to schools, offices and other establishments ahead of new strains that threaten to evade medicines.
Health authorities expect the initial supply of the J&J vaccine will help ease, though not eliminate, the frustration felt by people unable to sign up for shots because there aren’t enough doses available.
J&J has said it would deliver about 20 million doses for U.S. use by the end of March, which may be enough to boost the countrywide capacity for completed vaccinations by about 20%.
The two other Covid-19 vaccines authorized in the U.S. come from Moderna Inc. and from a partnership between Pfizer Inc. and Germany’s BioNTech SE. The companies have projected delivering enough of their two-dose vaccines by the end of March to immunize 100 million people.
Each of those vaccines require two shots to confer their full benefit. The J&J vaccine involves only one shot, a factor that also may ease the logistics of delivering doses.
The late-stage study evaluating J&J’s vaccine looked at how well it protected against moderate and severe Covid-19 among 43,000-plus volunteers in several countries.
In the U.S. alone, the vaccine was 72% effective, J&J said. The shot wasn’t as effective in South Africa alone, where a new and more transmissible variant of the virus has emerged. There, the vaccine was 57% effective.
Those companies’ trial results, however, occurred largely before new variants are known to have emerged.
Several Covid-19 vaccine makers including Moderna and J&J have said they are working on modified shots that could prove more effective against new Covid-19 variants.
The expected FDA action is known as an emergency-use authorization, a designation created by federal law to deal with situations like the current global pandemic.
It falls short of a full FDA approval. Yet the FDA has nevertheless required large clinical studies, as well as following study volunteers for a median of two months following vaccination.
J&J has said it expects to ship 100 million doses throughout the U.S. by late June and to supply more than one billion doses world-wide during 2021.
Pfizer and Moderna have committed to supplying enough doses by the end of July to vaccinate 300 million people in the U.S.
