The Food and Drug Administration may soon allow Americans to mix and match COVID-19 booster shots and be inoculated with a different vaccine than they initially received, The New York Times first reported on Monday.
The shift would be particularly notable for those who received the one-shot Johnson & Johnson vaccine. The Times noted that a recent report by an expert committee that advises the FDA found those who received that vaccine but got a Moderna booster saw antibody levels rise 76 times over in 15 days, compared with just a fourfold increase after a booster of the Johnson & Johnson jab.
A group of advisers on Friday recommended the FDA authorize a second shot of the Johnson & Johnson vaccine, with many members asking if the jab should actually be considered a two-dose regimen to begin with.
Antibody levels are an important metric to measure immune response from a vaccine, but not the sole factor in determining its efficacy. All of the approved COVID-19 vaccines have been shown to be safe and effective at preventing severe illness and death associated with the virus.
Bloomberg noted later Monday that the FDA is still considering the guidelines of the mix-and-match policy, which would give Americans more choice and may ease vaccine administration due to supply constraints. Agency officials could allow for widespread choice or narrow the guidance to specific cases. The Centers for Disease Control and Prevention will meet on Thursday to determine its own recommendations on the booster campaign.
The FDA authorized Pfizer-BioNTech booster jabs for many at-risk Americans last month, saying people age 65 and older, those with high-risk conditions and those who work in high-exposure jobs could receive a third shot to increase their protection against the coronavirus. The boosters are available at least six months after a person’s second dose and are meant to re-up waning protection amid the ongoing spread of COVID-19 fueled by the highly transmissible delta variant of the virus.
The Times added Monday that regulators are hoping to dramatically expand the number of Americans eligible for booster shots in the coming days as it considers boosters of the Moderna and Johnson & Johnson vaccines. Tens of millions of people could be eligible for the extra vaccinations by the end of the week.
This article originally appeared on HuffPost and has been updated.