Over the last year, the Johnson & Johnson COVID-19 vaccine has been commonly referred to as a single-shot alternative to the two-dose regimens of mRNA vaccines from Pfizer-BioNTech and Moderna.
But meeting Friday to consider whether to recommend approval of a booster dose for J&J's vaccine, an FDA advisory committee unanimously concluded that a second dose should be administered and suggested that the vaccine performs better as a two-dose series.
With that, the Vaccines and Related Biological Products Advisory Committee (VRBPAC) recommended unanimously for an emergency use approval for a second dose of the J&J vaccine, provided the first shot came at least two months ago. While the recommendation covered all adults, there was much discussion as to whether the second dose should be called a booster or not.
"I think this frankly always was a two-dose vaccine," said panelist Paul Offit, M.D., of the Children's Hospital of Philadelphia.
Despite the committee characterizing it as a two-shot vaccine, it also will be available to those who received the shot upon its rollout after authorization on Feb. 27. As of Wednesday, J&J had administered more than 15.2 million doses of its vaccine. Because data wasn’t readily available, it is uncertain how many of these recipients will be immediately eligible to receive a second dose of the vaccine.
The FDA will now weigh and refine the recommendation, with a decision likely to come next week.
Also on the table for the FDA is to decide whether to accept the VRBPAC recommendation from Thursday for an EUA of a half dose of the Moderna COVID-19 vaccine to be given as a third dose to those age 65 and older and others with conditions or occupations that put them at high risk. The recommendation is for that booster shot six months after completion of the two-dose primary series.
Last month, the FDA approved the Pfizer COVID-19 vaccine as a booster for the same population as the Moderna recommendation, again at six months after completion of the primary series.
What started on Friday as a complicated discussion about whether the panel should recommend a booster dose of the J&J vaccine at two, three or six months, became simplified when the experts concluded that the vaccine boosts antibody response and is safe as a two-dose series.
The advisors were swayed by compelling data from a phase 3 trial released last month that showed a second dose at two months provided 94% protection against symptomatic COVID and 100% protection against a severe form of the virus.
"I think there's more than adequate safety for a two-month boost. I'm less concerned about a six-month boost having additional problems," said Michael Kurilla, M.D. of the NIH. "Their data would suggest very good activity against variants and good durability even with a single dose. I'm inclined to just consider this a two-dose vaccine and that's probably how it should go forward."
After voting on the recommendation, the panel heard a presentation on data from an NIH study on mixing and matching booster doses. The data generally supports the use boosters that differ from what people received initially.