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- A second shot of Johnson & Johnson's single-dose vaccine boosted antibodies in lab study.
- The company said a booster shot could be given eight months after the original vaccine.
- J&J will now submit the data to the Food and Drug Administration, it said.
- See more stories on Insider's business page.
An extra dose of Johnson & Johnson's single-shot COVID-19 vaccine boosted antibody levels in a lab study.
J&J said in a press release on Wednesday that after the booster shot, antibody levels were nine times higher than after the original single-dose vaccine.
The announcement comes as the US prepares to roll out COVID-19 booster shots from September to help protect against the Delta variant, which has mutations that help it avoid the immune response.
Dr. Mathai Mammen, global head at Janssen Research & Development, said in a statement that the company planned to meet with officials to discuss the possibility of a booster at least eight months after the first dose.
About 14 million Americans have received J&J's shot, according to the Centers for Disease Control and Prevention.
The company didn't specify how many people were in the study, or how long after the first dose it gave the booster shot. The study hasn't yet been scrutinized by other experts in a peer-review.
Study participants over 65 years old were given a lower dose, J&J said. There was a "significant increase" in the antibody response in this group, as well as in people aged 18 to 55, it said. It didn't mention people aged 55 to 65.
Previous data from a small lab study that looked at the original single-shot vaccine showed antibodies against the Delta variant lasted eight months.
Dr. Dan Barouch, a virologist at Beth Israel Deaconess Medical Center in Boston, who was not involved in the booster trial but was involved in the July study, told the New York Times that it was "too early to guesstimate" real-world protection from J&J's latest study.
But he was "quite certain" that officials, including at the White House, "will use these data to likely justify or recommend a booster for J&J-vaccinated people, probably with a second shot of J&J," per CNN.
Those who have weakened immunity can already get an extra dose.