J&J Says COVID Booster Shot Increases Protection After Two Months

Johnson & Johnson announced that a booster dose two months after receiving the initial shot increases protection against symptomatic illness in trial participants.

Data released Tuesday from a clinical trial showed that study participants in 10 countries, including the U.S., who received a second dose of the vaccine two months later had 75 percent protection against the virus, the Wall Street Journal reports. U.S. participants had 94 percent protection.

A double dose of the vaccine showed participants at 100 percent protection against the virus at least two weeks after the second shot.

“We now have generated evidence that a booster shot further increases protection against Covid-19 and is expected to extend the duration of protection significantly,” J&J chief scientific officer Paul Stoffels said.

The study tested the booster vaccine in about 32,000 people over the age of 18 in the U.S., Belgium, Brazil, Colombia, France, Germany, the Philippines, South Africa, Spain and the United Kingdom.

J&J said that an extra shot given two months after the first boosted antibody levels four to six times higher than observed after the single shot. A booster administered six months after the first shot initially increased antibody levels nine times and continued to climb to 12 times higher four weeks after the second shot.