Here are answers to frequently asked questions about the shots produced by Moderna and Pfizer/BioNTech, based on information provided by the CDC and Keri Althoff, PhD, and virologist Andrew Pekosz, PhD, Johns Hopkins Bloomberg School of Public Health epidemiologists.
Question: Who is eligible for the new bivalent boosters?
Answer: The CDC greenlighted the upgraded Pfizer/BioNTech shots for Americans 12 and older and the Moderna booster for those 18 and over, if they have received a primary vaccine series or a booster at least 2 months before.
The boosters have been redesigned to protect against the predominant BA.4 and BA.5 strains of the virus. The Biden administration is making 160 million of the booster shots available free of charge through pharmacies, doctor’s offices, clinics, and state health departments.
Q: What about children under 12?
A: The new boosters are not approved for children under 12. Additional testing and trials need to be conducted for safety and effectiveness. But officials recommend that children 5 and above receive the primary vaccine series and be boosted with one shot. Children 6 months to under 5 years are not yet eligible for boosters.
Pfizer said it hopes to ask the Food and Drug Administration for authorization in 5- to 11-year-olds in October.
Q: How do the new bivalent boosters differ from previous shots?
A: The new shots use the same mRNA technology as the prior Moderna and Pfizer/BioNTech vaccines and boosters but have been upgraded to target the newer Omicron strains. The shots use mRNA created in a lab to teach our cells to produce a specific protein that triggers an immune-system response and make antibodies that help protect us from SARS-CoV-2, the virus that causes COVID.
The recipe for the new shots incorporates the so-called “spike protein” of both the original (ancestral) strain of the virus and more highly transmissible Omicron strains (BA.4, BA.5). Once your body produces these proteins, your immune system kicks into gear to mount a response.
It’s also possible – but yet to be determined – that the new bivalent boosters will offer protection against newer but less common strains known as BA.4.6 and BA.2.75.
Q: Are there any new risks or side effects associated with these boosters?
A: Health experts don’t expect to see anything beyond what has already been noted with prior mRNA vaccines, with the vast majority of recipients experiencing only mild issues such as redness from the shot, soreness, and fatigue.
Q: Do I need one of the new shots if I’ve already had past boosters or had COVID?
A: Yes. Even if you’ve been infected with COVID in the past year and/or received the prior series of primary vaccines and boosters, you should get a bivalent Omicron shot.
Doing so will give you broader immunity against COVID and also help limit the emergence of other variants. The more Americans with high immunity, the better; it makes it less likely other variants will emerge that can escape the immunity provided by vaccines and COVID infections.