The antibody increases were significant in those ages 18 to 55, the company said, and for those 65 and older who received a lower booster dose for the vaccine, named Janssen.
The single shot of the J&J vaccine generates immune responses that are persistent through eight months, according to Dr. Mathai Mammen, global head of research and development for Janssen.
“With these new data, we also see that a booster dose of the Johnson & Johnson COVID-19 vaccine further increases antibody responses among study participants who had previously received our vaccine,” Mammen said in a statement..
The company has been in discussion with government health agencies regarding the potential for boosters.
Federal officials previously announced plan to start booster shots for adults who received the first doses of the Moderna and Pfizer vaccines in the winter.
Those with compromised immune systems also are eligible for booster shots.