Bivalent COVID-19 Boosters

By: Dr. Joseph Mechak and Dr. Emily Atwood


On September 1, 2022 the CDC and FDA each signed off on two versions of a bivalent COVID-19 booster vaccine (Moderna and Pfizer).  We are very excited about this new tool in our fight against COVID-19 and wanted to take some time to educate our parents and patients about the vaccine and why it is important.


What vaccines were approved and who is eligible?

Both Pfizer and Moderna produced new bivalent booster vaccines that were approved under Emergency Use Authorization. The Pfizer bivalent booster is approved for children 12 and older while Moderna’s bivalent booster is approved for adults 18 and older. To be eligible for the bivalent booster, you must have received a primary series of a COVID-19 vaccine and it must be more than 2 months since your most recent vaccine dose (primary or booster). If you have recently had COVID-19, you are eligible for the bivalent booster once you have completed isolation but may elect to wait up to three months before receiving the booster.


What is a bivalent vaccine?

Bivalent refers to the fact that there is mRNA from 2-strains of COVID-19 contained within the vaccine.  The vaccine has the mRNA from the original vaccine that was designed against the alpha-variant of COVID-19 but also contains mRNA from the more recent BA.4/5 variants.  


Why is this updated formulation important?

The new mRNA from the BA.4/5 contained within the vaccine is a much closer match to the currently circulating strains of COVID-19. Data suggest that the better the vaccine matches the circulating variant, the better the vaccine will protect against contracting COVID-19 and severe illness. There is also some data that suggest these new vaccines may be more durable and provide longer lasting protection compared with our current vaccines. 


How do we know these vaccines are safe and effective?

The new bivalent vaccines contain only small modifications from the original COVID-19 vaccines. The FDA and CDC have concluded that they are both safe and effective in three primary ways:

  • The original COVID-19 vaccines are the most studied and scrutinized vaccines in history.  They have proven to be safe and effective through multiple studies and ongoing real time data analysis through VAERS (Vaccines Adverse Events Reporting System). The new bivalent vaccines contain only small modifications from these original vaccines. Our experience with the original vaccine strongly indicates that these too will be safe and effective.
  • Animal studies were conducted to ensure appropriate immune response and safety of the bivalent vaccines. This is the same process used to evaluate and approve the flu vaccine each year.
  • Clinical trials in the United States and worldwide are underway.  There were no surprises or concerns in preliminary data but we are still awaiting the final analysis of these trials. 


What are the side effects of the bivalent COVID-19 vaccines?

Several small studies suggest the side effect profile of the original vaccine and the bivalent vaccine are very similar in nature, scope, and severity. The main side effects include fever, fatigue, arm pain/soreness. Severe reactions and myocarditis remain a very rare side effect; in the rare instances when it has occurred, vaccine-related myocarditis typically affects adolescent and young adult males. 


Can I get the COVID-19 bivalent booster and the flu shot at the same time? What about routine vaccines?

Yes! The COVID-19 bivalent vaccine may be given at the same time as the flu vaccine or any routine vaccines.  Further, any recently administered vaccines will not impact the COVID-19 booster and should not delay vaccination. There is now a lot of data to say that immunity from the COVID-19 vaccine is not impacted by co-administration or recent administration of any routine or flu vaccinations. Side effects are similar if COVID and Flu vaccines are given at the same time.


Will this booster be available for children under 12 years old?

Probably.  The CDC and FDA are planning to meet in the coming weeks to discuss bivalent COVID-19 vaccine booster doses for the younger pediatric population. We will provide more information as it becomes available. 


Will Potomac Pediatrics have the bivalent COVID-19 vaccines?

Yes.  We are scheduled to receive doses of both Pfizer and Moderna’s bivalent vaccine as early as next week.  We will provide information and how to register for these vaccines when they become available. 


Additional materials

FDA Press announcement on bivalent COVID-19 boosters

Nature – Bivalent COVID-19 boosters

CDC – Meeting materials 9/1/2022

AAP – Press release about bivalent vaccine in teens and adolescents