Johnson & Johnson on Tuesday said a booster shot of its Covid-19 vaccine given two months after the first strengthens protection against moderate illness and severe disease.
The company said a late-stage clinical trial found that giving a second shot of the single-dose vaccine produced 75 percent protection against moderate and severe disease globally. That figure rose to 94 percent in the United States.
Giving a booster shot six months after the first dose also produced a twelvefold higher antibody level, J&J said.
The booster data has not yet been peer-reviewed or published in a scientific journal.
“Our single-shot vaccine generates strong immune responses and long-lasting immune memory," said Mathai Mammen, the global head of research and development at J&J's Janssen subsidiary. "And, when a booster of the Johnson & Johnson Covid-19 vaccine is given, the strength of protection against Covid-19 further increases.”
Just under 15 million people in the United States have gotten the J&J Covid-19 shot. The company said earlier this year that a single shot of its vaccine provided 66 percent protection against moderate and severe disease.
The bottom line: J&J's data comes as the federal government wrestles with when and how to roll out Covid-19 booster shots. Top White House and health officials last month backed a plan to roll boosters out broadly to most adults starting in late September. But that prompted fierce pushback from health experts in and out of the government, who argued that there was not yet sufficient data to justify a broad booster campaign.
Matters came to a head on Friday, when the FDA's independent vaccine advisory committee rejected the idea of allowing Pfizer and BioNTech's Covid-19 booster to be used in people 16 and older, arguing that the available safety and efficacy data did not justify that far-ranging use. Instead, the panel voted in favor of giving the Pfizer-BioNTech booster to people over 65 and those at high-risk of severe disease.
It is not clear how closely FDA will hew to its advisory panel's recommendation. The agency has yet to act on booster applications from Pfizer-BioNTech and Moderna.
What's next: J&J said it submitted its booster data to FDA and planned to also share it with regulators in other countries.