- People vaccinated with one of the three coronavirus vaccines licensed in the U.S. could benefit from receiving a different booster dose than the first, a study Administered by the National Institutes of Health and published online Wednesday, it offers important new data for public health officials and regulators.
- In the study, which recruited about 450 people who had been vaccinated with the Pfizer, Moderna or Johnson & Johnson vaccines, an additional dose of any of the three injections stimulated many times higher immune responses. While there are important limitations, including study size and follow-up, the data suggest that a more flexible approach to booster doses might be possible.
- The results come a day before advisers to the Food and Drug Administration begin a two-day meeting to debate whether to recommend the authorization of booster doses of the Moderna and J&J vaccines. The FDA approved a Pfizer booster for many Americans September 22.
Scientists at the FDA and the Centers for Disease Control and Prevention have been grappling with the question of who needs an extra dose of vaccine, and when, for weeks.
The authorization of a third dose of the vaccine from Pfizer and BioNTech for certain groups at the end of September left without guidance the tens of millions of Americans who received the injection of Moderna or J&J for their initial vaccination. CDC data shows that nearly 9 million Americans have received a booster vaccination to date, although it does not distinguish whether they were part of groups authorized to receive one. Reports indicate Americans across the country are looking for backup, even if one isn’t recommended yet.
In the NIH study, 458 volunteers who had been fully immunized with the Pfizer, Moderna, or J&J injections received a booster four to six months after completing their initial vaccine regimen. They were divided into groups based on which vaccine they received first, then were given an equivalent booster from the same developer or an injection of one of the other two.
In all cases, the additional dose increased levels of antibodies against the coronavirus, a change that is generally associated with increased protection against COVID-19.
But the results suggested that a boost from Moderna and Pfizer’s mRNA vaccines raised antibody levels much higher than J & J’s. This was particularly the case for people who received the J&J vaccine initially and had lower levels to begin with. Volunteers who received the two-dose regimen of Moderna or Pfizer and received either of those for an additional dose had more closely comparable antibody levels afterward.
In particular, however, the dose of Moderna used in the study was the currently licensed 100-microgram dose, rather than the 50-microgram dose that the company has requested to be licensed as a booster vaccine.
There were other limitations as well. Participants were not randomized or segmented based on the time elapsed since the last vaccination. The researchers further noted that the follow-up period was too short to detect more rare or late-onset side effects from the booster doses. It is also not clear yet for how long an increase in antibody levels could lead to greater protection after a third dose.
“These data suggest that if a booster vaccine is approved or licensed, an immune response will be generated regardless of the primary Covid-19 vaccination regimen,” the researchers wrote. His work has not yet been peer-reviewed and was available online on the medRxiv “prepress” server.
A third dose of Pfizer’s vaccine is currently licensed six months after the first two for adults 65 years of age and older, young adults with underlying medical conditions, and individuals 18 years of age and older whose “frequent institutional or occupational exposure” puts them at increased risk. of contracting severe COVID-19. . Immunosuppressed people are also eligible for a third dose of the Pfizer or Moderna vaccine, although in that case the additional injection is because they are less likely to have had a sufficient immune response with two.
On Thursday and Friday, the FDA advisory committee I want to discuss authorizing boosters for Moderna and J&J vaccine recipients more broadly. Moderna requested an authorization that matches what has been licensed for the Pfizer vaccine, while J&J is requesting a booster authorization for people over 18 years of age.
The committee will hear from the NIH on the results of the momentum study on Friday, though by then, they will have already voted on their recommendations, according to the meeting schedule.