A booster dose of the one-shot Johnson & Johnson COVID-19 vaccine sparked a “rapid and robust increase” in antibodies that bind to the coronavirus’ spike protein, the company said Wednesday, as drugmakers work with federal officials to fight off the delta variant and ensure the lasting power of immunization.
J&J, based in New Jersey, said antibodies increased by nine-fold in people who received a second dose, compared to what is measured 28 days following a single dose. The “significant” increases were observed in trial participants ages 18 to 55 and those 65 and older who received a lower booster dose.
“We have established that a single shot of our COVID-19 vaccine generates strong and robust immune responses that are durable and persistent through eight months. 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,” said Dr. Mathai Mammen, the global head of Janssen Research & Development, a pharmaceutical arm of J&J.
The company said it is discussing authorization of a booster dose with the Food and Drug Administration, European regulators and other global health authorities amid general fears that fast-moving variants and the march of time will decrease the effectiveness of the vaccines against the pandemic.
J&J used an inactivated virus, or adenovirus-vector, for its one-shot vaccine. It got a later start in its U.S. and global rollout than Pfizer-BioNTech and Moderna, each of which made two-shot vaccines that rely on messenger-RNA to teach the body how to recognize and fight the coronavirus.
U.S. officials recently outlined a plan to let Americans seek a third dose of the mRNA versions eight months after receipt of the second dose. The booster rollout is scheduled to begin Sept. 20 for high-priority persons, like health workers and nursing home residents, who kicked off the initial rollout in December.
The J&J vaccine has generally produced a lower efficacy than its mRNA rivals in trials.
The one-shot version is considered very good at staving off bad outcomes from the disease. A Yale Medicine study found it is up to 71% effective against hospitalization from the delta variant and up to 95% against death.
Roughly 14 million people in the U.S. have been fully vaccinated by the J&J version compared to 92 million with the Pfizer vaccine and 64 million with the Moderna shots, according to the Centers for Disease Control and Prevention.
The J&J version wasn’t approved for emergency use until late February, compared to mid-December for the other vaccines, and manufacturing problems hampered its distribution in the early months.