Johnson & Johnson said it performed two studies in which volunteers received a second vaccine dose between two and six months after the first. File Photo by Szilard Koszticsak/EPA
Sept. 21 (UPI) -- Johnson & Johnson announced on Tuesday that its one-shot COVID-19 vaccine has performed well in real-world studies, offers long-lasting protection against the virus and boosts the immune system when administered as a booster a few months after the original dose.
The pharma company made the announcement in a release of late-stage clinical data for the adenovirus-based vaccine, produced by Johnson & Johnson subsidiary Janssen, which was given emergency use authorization in the United States early this year.
Johnson & Johnson said it performed two studies in which volunteers received a second vaccine dose between two and six months after the first. It said the booster led to an increased immune response in recipients between 18 and 55 years old.
When given two months after the first dose, the company said the booster shot was 100% effective in protecting recipients from severe COVID-19 and was 75% effective in preventing symptomatic COVID-19 worldwide. It was 94% effective in preventing symptomatic COVID-19 in the United States, the data said.
"When a booster of the Johnson & Johnson COVID-19 vaccine was given two months after the first shot, antibody levels rose to four to six times higher than observed after the single shot," the company said in a statement.
In another study that tested a booster dose after six months, Johnson & Johnson said it observed antibody increases between nine and 12 times higher in recipients.
The company also noted that one dose of the vaccine showed to be 79% effective against infection in the United States between March and late July, and 81% effective in preventing hospitalization.
"There was no evidence of reduced effectiveness over the study duration, including when the Delta variant became dominant in the U.S.," it noted.
"Our single-shot vaccine generates strong immune responses and long-lasting immune memory. And, when a booster of the Johnson & Johnson COVID-19 vaccine is given, the strength of protection against COVID-19 further increases," Global Head of Janssen Research and Development Dr. Mathai Mammen said in a statement.
The clinical data released on Tuesday has not yet been peer-reviewed.
Johnson & Johnson added that it's in talks with U.S. and European regulators about possible booster doses. Last week, the Food and Drug Administration recommended a booster for Pfizer's vaccine in Americans over 65 and those at greater risk.