Study finds ‘mixing and matching’ boosters safe, but Moderna, Pfizer are best

Receiving a booster dose of a different vaccine than what was initially administered is safe and effective, though people who received Johnson & Johnson’s vaccine may get more benefit from a booster of an mRNA vaccine such as Pfizer’s or Moderna’s, according to data released Wednesday.

A highly anticipated preprint study on “mixing and matching” vaccines from the National Institutes of Health found that boosting with any of the three vaccines currently licensed or authorized for emergency use in the U.S. will generate an immune response.

However, people who received a booster dose of either the Moderna or Pfizer vaccines had a higher increase in their antibody responses more often than those who received an extra dose of J&J, according to the study, which has not yet been peer reviewed.

The results: People who received an mRNA-based booster vaccination had a four-fold increase in their neutralization response more frequently than those who were boosted with J&J’s adenovirus vaccine.

A booster dose of Moderna’s vaccine provided the highest boost of neutralizing antibodies in people who received any of the other vaccines as the primary dose. Those who received a prime dose of Moderna’s vaccine and the same booster had the highest levels of immune response. But the increase in immune response of a Moderna booster compared to a Pfizer booster was likely not significant enough to make a noticeable difference.

What’s next: The data from the study will be presented to an outside advisory panel of the Food and Drug Administration later this week as part of a series of meetings to consider requests from both Moderna and J&J to authorize booster doses of their vaccines.