Early results from research by a team led by the National Institutes of Health suggest that giving people a different type of booster shot from their original vaccine elicited a stronger immune response than giving an additional dose of the same vaccine. This is consistent with the findings of research conducted earlier this year in the UK.
Pfizer and Moderna Vaccines are both mRNA vaccines, made using genetic material called lipid-coated messenger RNA to instruct the body’s cells to make small pieces of coronavirus to stimulate an immune response . Johnson & Johnson’s Janssen vaccine uses a different method: a genetically engineered common cold virus called an adenovirus, which cannot replicate itself, but it can deliver a small piece of coronavirus to cells and a May also stimulate an immune response.
extensive immune responses
Combining different types of vaccines can broaden the type of immune response, said Dr Angela Branche, an assistant professor at the University of Rochester School of Medicine, who is helping drive some clinical trials by combining booster doses. Is.
A vector vaccine, like the Janssen or AstraZeneca vaccine, stimulates strong cellular immunity, she said. mRNA vaccines stimulate a powerful surge of antibodies. Combining the two, she said, “can increase the depth of the immunological response.”
“I think the data will show that boosting is certainly likely to be very effective in providing additional and longer protection,” she told Granthshala. “We will all be able to promote that with vaccines.”
Last week, Professor of Medicine at the University of Maryland, Dr. Kirsten Laik presents what the NIH team has found so far to vaccine advisers from the US Food and Drug Administration. The FDA asked him to address the question of mix-and-match boosters and is preparing emergency use authorization language for the boosters that might incorporate his ideas.
While Laeke stressed that the data was incomplete, he said that boost with a different type of vaccine from the original dose provided a stronger antibody response than boost with the same type.
“What I would note is that there is an increase in neutralizing antibodies in response to any boost in the primary vaccination chain,” she told the FDA’s Vaccines and Related Biological Products Advisory Committee. “The study wasn’t designed to make comparisons between boosts,” she said — in other words, it can’t tell people which particular brand might be best to boost with.
But it doesn’t matter, because the other benefit of allowing people to be promoted in the US with any of the three authorized vaccines would be flexibility.
messy messages around booster
Right now the booster permissions are complicated. Pfizer has emergency use authorization for a booster shot for people who are at least six months out of their fist two doses, who are 65 or older, or who are 18 years of age and older and Those who are at risk of serious illness because of an underlying condition. Or because their living or working conditions put them at risk.
Moderna and Johnson & Johnson have also sought permission for the booster. Moderna’s Ask is an almost perfect mirror of Pfizer’s, but Johnson & Johnson is asking for boosters for everyone age 18 and older who have received its vaccine. If the FDA approves those requests, VRBPAC members said, people would be confused.
Professor of Biostatistics at the University of Arkansas, Dr. “Now you have established the possibility of mixing, matching and being eligible for different groups,” Janet Lee said at Friday’s meeting.
“It’s going to be very, very messy in terms of messaging.”
Dr. Amanda Cohn, an official with the US Centers for Disease Control and Prevention who sits on both VRBPAC and the CDC’s Vaccine Advisory Committee, said it would be very helpful if there could be flexibility for people trying to give boosters – For example, to drug retailers going to nursing homes with only one brand of vaccine.
In addition, there is the issue of people who forgot which vaccine they received or who lost their record, notes Dr. Melinda Wharton, CDC’s associate director for vaccine policy.
What can happen next?
Dr. Peter Marks, who heads the Center for Biologics Evaluation and Research, the vaccine arm of the FDA, gave some heavy hints about the agency’s direction.
“I think we got what we needed from this discussion,” he said. “There seems to be some general consensus that this is an important option for people,” he said. “Some people think this is enough data.”
This points to the possibility of an FDA emergency use authorization for a booster covering all three vaccines. CDC Vaccine Advisors, the Advisory Committee on Immunization Practices, meet on Thursday to provide guidance on giving boosters.
The ACIP and CDC can narrow down the FDA’s standards in giving the final word on boosters, but cannot elaborate them.
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