Johnson & Johnson
The drugmaker also said its booster dose increases antibody levels by four to six times compared to only one shot. Moreover, J&J found that a booster dose given six months out from the first shot may be potentially even more protective against infection, generating antibody levels twelvefold higher.
The vaccine was also found to be well tolerated by participants when given as a booster, with side effects similar to those seen after the first dose, J&J said.
"Our single-shot vaccine generates strong immune responses and long-lasting immune memory," said Dr. Mathai Mammen, global head of Janssen Research & Development, in a press statement. "When a booster of the Johnson & Johnson COVID-19 vaccine is given, the strength of protection against COVID-19 further increases."
The company found that a booster shot of its COVID vaccine brings its efficacy rate to 94% in the United States. Globally, however, the booster shot given two months after the first dose is only 75% effective against symptomatic infection. Still, the booster shot demonstrated 100% effectiveness against both severe infection and hospitalization, J&J said.
The new data helps J&J as it seeks Food and Drug Administration emergency use authorization for its booster shot to help further protect those who have received the drugmaker's single-shot vaccine. U.S. health officials said that they need more data on the J&J vaccine and a potential booster dose before they can recommend a second shot. According to data from the Centers for Disease Control and Prevention, about 14.9 million Americans have received the J&J vaccine.
But booster shots may not be J&J's primary objective.
The company also released data from a real-world study alongside its booster shot data, demonstrating that a single dose of its vaccine provides strong, long-lasting protection against severe COVID infection, hospitalization and death, with the vaccine being 81% effective after several months.
"It is critical to prioritize protecting as many people as possible against hospitalization and death given the continued spread of COVID-19," said Dr. Paul Stoffels, chief scientific officer at Johnson & Johnson, in a press statement. "A single-shot COVID-19 vaccine that is easy to use, distribute and administer, and that provides strong and long-lasting protection is crucial to vaccinating the global population."