The Food and Drug Administration is expected to authorize boosters for Moderna and Johnson & Johnson vaccines as soon as Wednesday, with the possibility people will not get the additional dose from the maker of their initial inoculation.
The mix-and-match approach, which also could allow healthcare providers to recommend any booster, would add significantly to the number of Americans eligible for a booster. The FDA last week reviewed mix-and-match data from the National Institutes of Health from small studies that showed much greater protection for recipients of the Johnson & Johnson vaccine from a booster using a Moderna or Pfizer-BioNTech vaccine, each developed with messenger RNA technology.
In the study, a Moderna booster produced a 76-fold increase in antibody levels among the Johnson & Johnson recipients. A Pfizer-BioNTech increased antibody levels 35-fold, with a Johnson & Johnson booster producing only a fourfold increase.
“The recommendations will be driven by the science,” says Dr. Ulysses Wu, Hartford HealthCare’s System Director of Infection Disease and Chief Epidemiologist. “It is likely that mixing and matching of vaccines will be allowed but we still have to see what the formal recommendations will be. If FDA does go ahead and approve, practitioners will be able to prescribe either the same vaccine they had previously received or they can mix mRNA vaccines or mix mRNA vaccines with adenovirus-based (J&J) vaccines.”
It’s likely, however, that mix-and-match will be an option only, perhaps for people who might not have had access to their original vaccine or experienced a bad reaction to an mRNA vaccine. The FDA reportedly will recommend sticking with the same vaccine. For those who mix-and-match, what dosage would the FDA recommend if a Moderna vaccine is used as a booster for a Johnson & Johnson recipient? For those who originally received the Moderna vaccine, a Moderna booster is expected to be a half-dose. Should it be that same half-dose for someone who originally received Johnson & Johnson?
“The process is becoming very complex very fast,” says Eric Arlia, Hartford HealthCare’s Senior Director of Pharmacy.
The FDA authorized Pfizer-BioNTech booster shots last month for anyone age 65 or older and some at-risk Americans at least six months after receiving a second dose. More than 104.5 million Americans have received the initial “fully vaccinated,” two-dose treatment, with 69.5 million fully vaccinated with the Moderna vaccine. More than 15 million people have been vaccinated with the single-dose Johnson & Johnson vaccine.