J&J vaccine shown to maintain effectiveness over time; booster adds up to 6 times more antibodies than first dose

Johnson & Johnson today said its phase 3 trial data confirms its vaccine's durability and provided evidence of a second, booster shot's effectiveness against COVID-19. The drug maker said that, over the course of its ongoing phase 3 trial, it found no evidence of the vaccine's reduced effectiveness, which J&J said is 79% for preventing COVID-19-related infections and 81% for preventing COVID-19-related hospitalizations. J&J furthermore found that a booster shot administered 56 days after an initial dose provided 100% protection against severe/critical COVID-19 for at least 14 days post-final vaccination and 94% protection against symptomatic (moderate to severe/critical) COVID-19 in the U.S. Additionally, boosters resulted in antibody levels four to six times higher than those netted from a single dose.