Both Pfizer and Moderna have asked FDA to authorize “bivalent” COVID-19 vaccine booster shots, and they could be available to people 12 and up as early as the first week of September.
Bivalent means that the vaccine is designed to protect against two strains of the virus. In this case, the two strains are the original “Wuhan” strain and a subvariant of the Omicron strain.
Pfizer has asked for authorization to offer this bivalent vaccine to people age 12 and up, and Moderna has asked for authorization for people 18 and up. For now, there is no word on when a bivalent vaccine might become available for kids younger than age 12, but one CDC planning document says “It is expected that at least one bivalent vaccine for children ages 11 years and younger may be authorized within a short time.”
The FDA is reviewing data from animal studies now. These specific formulations have not been tested in humans, but very similar formulations *were* tested in humans in the Spring. They showed a good safety profile and a strong immune system reaction. There’s no good reason to think that a small tweak to the target virus subvariant would make any difference in terms of safety, tolerability, or effectiveness. For example, every year the influenza vaccine is updated to target new variants, and it similarly does not go through a full clinical trial process.
CDC’s Advisory Committee on Immunization Practices will meet on September 1 & 2 to discuss who should get the updated booster. Once CDC decides, it will roll out to pharmacies within a few days.
Pfizer’s bivalent booster is a 30 microgram dose (the same as their previous booster). Moderna’s bivalent booster is a 50 microgram dose (also the same as their previous booster).
We do not yet know for sure who the CDC will recommend to get the new bivalent boosters, but it seems likely to be all people in the appropriate age range (12+ for Pfizer and 18+ for Moderna)–as long as it has been 5 months since their most recent vaccine/booster dose. We also don’t know what the advice will be about mixing-and-matching, but historically the CDC has said mix-and-match boosters are OK. More soon on this one, folx!