The FDA recently authorized COVID-19 bivalent boosters and the CDC recommended them for everyone 12 years and older.
Q: What is a “bivalent” booster?
A: Both Moderna and Pfizer boosters contain mRNA that code for the spike protein of the original Wuhan-hu-1 strain and the spike protein of the Omicron variant lineages BA.4 and BA.5. The BA.4 and BA.5 variants differ in several ways, but their spike
proteins are identical.
Q: Why did they not produce just an Omicron monovalent vaccine?
A: It was important to include the original Wuhan-hu-1 strain as the virus may mutate out of the Omicron lineage. We do not know what variant may come next and it may be more like the original than Omicron.
Q: Is the bivalent booster necessary?
A: It is unknown. The original mRNA vaccines are very good at preventing hospitalization and death but not as good at preventing milder infections. The vaccines could be better as about forty percent of hospitalization are among the vaccinated. Clinical
trials demonstrate that people boosted with bivalent vaccines produce antibodies good at neutralizing Omicron variants. Hopefully, these antibodies will decrease serious illnesses even further. Trials studying effectiveness are underway.
Q: Why do some vaccinated people still end up being hospitalized?
A: To be clear, nearly 70 percent of the U.S. population has received their primary COVID-19 vaccine series. The 30 percent who are unvaccinated make up 60 percent of the hospitalizations. Those vaccinated individuals who develop severe disease are more
likely to be 85 years or older or have other health conditions that place them at risk. Their health conditions tend to be so serious that even the common cold may put them in the hospital. There are also “healthy” individuals who appear
to be genetically vulnerable to COVID-19. Still, everyone does better vaccinated than not.
Q: Who can receive a bivalent booster?
A: Anyone 12 years and older who received their primary series if it is at least 2 months since their last COVID-19 vaccine. The Pfizer bivalent is approved for those 12 and older and the Moderna bivalent is approved for those 18 and older. A bivalent
vaccine has not been approved for younger children.
Q: What if I just had COVID-19?
A: It is likely you had the Omicron variant and so it is reasonable to wait three months to get boosted, as natural immunity is protective for at least that long. But if you want, it is fine to receive the booster as soon as you are out of isolation.
Q: Can I receive other vaccines like the flu shot at the same time?
A: YES! It is a great idea to get both the bivalent COVID-19 and flu shots at the same time. The one exception is for young men under 30 who received the monkeypox vaccine; it is best for them to wait four weeks before receiving a COVID-19 vaccine
to minimize the rare risk of inflammation of the heart.
is written by Sealy Institute for Vaccine Sciences faculty members Drs. Megan Berman
, an associate professor of internal medicine, and Richard Rupp
, a professor of pediatrics
at the University of Texas Medical Branch. For questions about vaccines, email firstname.lastname@example.org