This Wednesday, the U.S. Food and Drug Administration authorized the new bivalent Moderna and Pfizer vaccines for use as a single booster dose.
Also referred to as “updated boosters,” these vaccines contain two messenger RNA (mRNA) components of the SARS-CoV-2 virus: the original formulation and one targeting BA.5 — now the dominant version of the virus — as well as a sister subvariant of Omicron.
In the same decision, the FDA revoked the use of the original monovalent vaccines as boosters. However, they continue to be authorized for use among those who have not yet been vaccinated.
“Based on the...