Johnson & Johnson (J&J) announced today that a second dose of its COVID-19 vaccine, given months after a first dose, robustly boosted antibodies that target the SARS-CoV-2 coronavirus in a small group of volunteers.
The company has not yet published the detailed data in a scientific journal, but said they were submitted yesterday for posting on the preprint server medRxiv. In its press release, J&J said the booster shot raised levels of antibodies ninefold in the volunteers compared with their levels 28 days after a single-dose injection of the vaccine, which earned an emergency use authorization from U.S. regulators in February. The company’s research involved just 17 volunteers. The New York Times reported that the booster was administered 6 months after they received the first J&J shot.
President Joe Biden’s administration announced last week it planned to begin offering boosters to recipients of the Pfizer and Moderna vaccines in late September, and that recipients would become eligible 8 months after their second dose of a messenger RNA (mRNA) vaccine. The plan did not include the J&J vaccine, the only one authorized for single-dose use in the United States. Unlike the mRNA vaccines, it uses a common cold virus called an adenovirus to deliver a gene that directs cells to produce the spike protein that studs the surface of the pandemic coronavirus. The U.S. Food and Drug Administration (FDA) has not yet approved any booster plan, except for the immunocompromised.
J&J now hopes to be included in any U.S. booster plan, said Mathai Mammen, global head of Janssen Pharmaceuticals R&D, the division that developed the vaccine, in a statement. “We look forward to discussing with public health officials a potential strategy for our Johnson & Johnson COVID-19 vaccine, boosting eight months or longer after the primary single-dose vaccination.”
Peter Marks, director of FDA’s vaccine-approving division, tells ScienceInsider the agency will review the new J&J data. “We are going to look at those data in the context of all other data available—in that context, it might help get there, despite the small number of subjects studied.”
Results from a separate vaccine efficacy trial of two J&J doses administered 2 months apart are expected in the coming weeks, and will likely be even more crucial to determining the vaccine’s role in fighting COVID-19.
Some observers are not persuaded that the new antibody data will materially affect the uptake of J&J’s product in the United States, where a minority of the vaccinated have received it. The J&J vaccine has been administered to 14 million people in the United States.
“A second [J&J] dose does increase antibody levels. But it seems unlikely this observation will drive many more Americans to now take a first J&J dose, given that the two-dose mRNA vaccines are so well established,” says John Moore, an immunologist at Weill Cornell Medicine.
With reporting by Jon Cohen.