The agency also said today that it will allow “mix-and-match” boosters — eligible people who are already fully vaccinated can get a booster dose of any of the three vaccines, regardless of which they started with.

As with the Pfizer / BioNTech booster, the FDA cleared third Moderna shots for vulnerable groups, including people 65 years of age and older, those who are at high risk of severe disease, and people at high risk of exposure to COVID-19 at work.