Americans who got Johnson & Johnson’s single-dose coronavirus vaccine may be better protected if they get a booster shot from Pfizer or Moderna, preliminary findings from a new government study suggest.
Published on the preprint server medRxiv and yet to be peer-reviewed, the National Institutes of Health study found mixing different coronavirus vaccines was safe and effective, but booster shots made by Moderna and Pfizer produced more robust immune responses than Johnson & Johnson’s booster shots did.
The findings will be presented to a U.S. Food and Drug Administration advisory panel on Friday, the second of two days of meetings where the emergency use authorization of booster shots from Moderna and Johnson & Johnson will be weighed by vaccine experts.
Whether the FDA might authorize the mix-and-match approach is unclear, The New York Times reports. The strategy will be discussed during the Friday meeting, but no vote will be taken. If regulators come to the conclusion that there is enough science to support the approach, they would likely need to update the authorization language of the Moderna and Pfizer-BioNTech vaccines to allow for their use in people who first received Johnson & Johnson’s shot.
What the study shows
In the NIH study, researchers looked at nine groups of roughly 50 people each. Each group received one of the three authorized vaccines, followed by a booster. In three groups, volunteers received the same vaccine for a boost. In the other six, they got a different vaccine.
The differences were startling: Those who got a J&J shot followed by a Moderna booster saw their antibody levels rise 76-fold within 15 days, while those who got a second dose of the J&J vaccine saw only a fourfold rise during the same period. A Pfizer booster shot raised antibody levels in Johnson & Johnson recipients 35-fold. The Moderna and Pfizer vaccines are both mRNA vaccines, while the J&J vaccine uses an adenovirus to deliver the vaccine to the immune system.
“These data suggest that if a vaccine is approved or authorized as a booster, an immune response will be generated regardless of the primary COVID-19 vaccination regimen,” the researchers wrote in the study.
What are the side effects?
Still, the NIH researchers noted the study’s small size and added that volunteers haven’t been followed long enough to identify rare side effects. However, there were no immediate serious side effects tied to the booster shots, the researchers add. Two participants vomited after