The U.S. Food and Drug Administration yesterday amended its emergency use authorizations for several actions regarding booster doses of COVID-19 vaccines, including allowing the use of heterologous, or “mix and match” booster doses: using a different type of vaccine from the primary dose for a booster dose.

Amendments also address times between primary doses and boosters and clarify that people with “frequent institutional or occupational exposure” to COVID are eligible for Moderna and Pfizer boosters.

The FDA amendments stated in full:

• The use of a single booster dose of the Moderna COVID-19 vaccine that may be administered at least 6 months after completion of the primary series to individuals:
• 65 years of age and older
• 18 through 64 years of age at high risk of severe COVID-19
• 18 through 64 years of age with frequent institutional or occupational exposure to SARS-CoV-2
• The use of a single booster dose of the Janssen (Johnson and Johnson) COVID-19 vaccine may be administered at least 2 months after completion of the single-dose primary regimen to individuals 18 years of age and older.
• The use of each of the available COVID-19 vaccines as a heterologous (or “mix and match”) booster dose in eligible individuals following completion of primary vaccination with a different available COVID-19 vaccine.
• To clarify that a single booster dose of the Pfizer-BioNTech COVID-19 vaccine may be administered at least 6 months after completion of the primary series to individuals 18 through 64 years of age with frequent institutional or occupational exposure to SARS-CoV-2.