Johnson & Johnson: One-Shot COVID-19 Vaccine 66 Percent Effective in Global Trial

Novavax reports interim trial results of its vaccine candidate

A clinician prepares to administer investigational Janssen COVID-19 vaccine in September 2020. Johnson & Johnson via AP

A clinical trial showed that Johnson & Johnson’s COVID-19 vaccine is 66 percent effective at preventing moderate to severe disease, the company said Friday.

That level of protection came 28 days after vaccination, according to data from a global phase 3 trial. Onset of protection was observed as early as day 14.