As the FDA moves to authorize boosters of the Moderna and Johnson & Johnson COVID-19 vaccines, expected no later than Wednesday night, the regulator appears receptive to brand flexibility in the choice of additional doses. An advisory committee to FDA heard evidence last week showing that people who initially received J&J’s single-dose vaccination saw antibody levels increase fourfold about 2 weeks after receiving a booster from the same company but registered a 76-fold gain after receiving a booster from Moderna.
In presenting the data, University of Maryland School of Medicine professor Kirsten E. Lyke warned that the study “was not powered or designed to compare between groups” and, thus, there is no proof than any particular combination of vaccines was most effective. People close to the matter say FDA is unlikely to explicitly recommend one brand over the other, but rather may leave that decision up to vaccine providers.