Johnson & Johnson said last month that a second shot, delivered around eight weeks after the first, increased its efficacy to around 94% against moderate to severe forms of the deadly virus, which has taken the lives of more people than the Spanish flu epidemic of 1918. Efficacy of Johnson's single-dose regime was pegged at around 70%.
A second shot of Johnson & Johnson's vaccine after two months boosted antibody levels fourfold, the company said at the time, while extending that interval to six months produced a twelve-fold increase.
Johnson & Johnson said the data it filed with the FDA, as part of its request to amend the Emergency Use Authorization order from earlier this year, was consistent with figures released in September.
"Our clinical program has found that a booster of our COVID-19 vaccine increases levels of protection for those who have received our single-shot vaccine to 94 percent. We look forward to our discussions with the FDA and other health authorities to support their decisions regarding boosters," said Janssen Research & Development head Mathai Mammen. "At the same time, we continue to recognize that a single-shot COVID-19 vaccine that provides strong and long-lasting protection remains a crucial component to vaccinating the global population."
Johnson & Johnson shares were marked 0.55% higher in early trading Tuesday to change hands at $160.02 each, a move that would nudge the stock into a 1.7% gain for the year.
Last month, a panel advising the FDA recommended boosters of the two-shot Pfizer (PFE) - Get Free Report vaccine to Americans over the age of 65, as well as to workers at high risk of infection from their day-to-day jobs, but decline to make a similar recommendation for the broader public.