The FDA said Wednesday that Johnson & Johnson’s single-dose vaccine protects against COVID-19. The Food and Drug Administration’s scientists confirmed that overall the vaccine is about 66% effective at preventing moderate to severe COVID-19. The agency also said the Johnson & Johnson version of the vaccine could help speed the process because it requires just one dose instead of two. In studies, it was highly effective against the most serious symptoms, and early results showed no hospitalizations or deaths starting 28 days after vaccination. The Johnson & Johnson vaccine would become the third option once it’s approved.