Bivalent Omicron COVID-19 Boosters: Effectiveness, Safety, and Other Important Information

An MSK employee (seated) receives a COVID-19 vaccination.

New bivalent booster shots are administered in the exact same way as previous COVID-19 vaccines.

You may have read about COVID-19 booster shots that provide protection against Omicron subvariants BA.4/5.

At Memorial Sloan Kettering Cancer Center (MSK), we recommend our patients strongly consider getting a booster shot as soon as they are eligible, in order to have the best possible protection from tCOVID-19.

Mini Kamboj

Mini Kamboj

Mini Kamboj, Chief Medical Epidemiologist at MSK, has answers to common questions about the shots.

What does it mean that these boosters are bivalent? How are they different?

The term “bivalent” means that they target two strains of COVID-19: the original strain that first appeared in the U.S. in early 2020 and the Omicron subvariants BA.4 and BA.5 that emerged more recently in the summer of 2022. The news media has also referred to these booster shots as “Omicron-specific.”

These bivalent boosters are made by Pfizer-BioNTech and Moderna using the same technology as the monovalent vaccines that have been given to more than 200 million people in the U.S. They are mRNA vaccines and they work in the exact same way as the original vaccines, but they have been updated slightly for added protection against Omicron BA.4/5.

Since the COVID-19 virus continues to change, it is important that vaccines keep pace. This is not a new approach. Each year, there are new dominant strains of the flu. Scientists create a seasonal flu vaccine that target these strains. The FDA has been planning the same for COVID-19 vaccines and has now taken an important first step: Scientists will regularly produce an updated vaccine so people have the best protection against strains that are spreading or are predicted to spread.

How effective are the bivalent Omicron boosters?

It is well understood that staying up to date on your vaccinations provides strong protection against severe disease, hospitalization, and death from COVID-19. The CDC published data in early December 2022 showing that bivalent boosters provided significant additional protection for people who had received monovalent shots. Omicron subvariants are predicted to continue to circulate. Improving protection against this variant is of vital importance.

Are the bivalent Omicron boosters safe? How do we know?

These vaccines work in the same way as the original COVID-19 vaccines and booster shots, and they are made using the same process. Clinical studies and real-life data on bivalent boosters so far show that people experience the same side effects as the monovalent vaccines.

To date, more than 657 million doses of COVID-19 vaccine have been given in the U.S. Serious side effects are treatable and have been very rare.

It’s important to note that the FDA, the Centers for Disease Control and Prevention (CDC), and companies that make the vaccines have been rigorously monitoring safety data for primary vaccines and booster shots. That crucial work is continuing with these bivalent boosters.

Am I eligible to get a bivalent Omicron booster?

The single-dose bivalent booster is authorized for everyone age 6 months and older who have completed their primary series of COVID-19 vaccination. (The CDC’s website has information about how many doses you need to complete your primary series.)

People who have received more than 1 original (monovalent) booster are also recommended to get a bivalent booster.

You must wait 2 months from your most recent COVID-19 shot to get a bivalent booster.

For young children, there are a few essential things to know:

  • Children age 6 months through 5 years who got the 2-dose Moderna vaccination must also wait 2 months for a bivalent shot.
  • The Pfizer vaccination for children age 6 months through 4 years is given as a 3-dose series. These children who get the Pfizer vaccination can get the bivalent shot as their 3rd dose. If they already received all 3 Pfizer shots, they are not eligible to get a Pfizer bivalent shot (which would be their 4th dose).

What about people who have cancer or have had cancer? Can they get the bivalent booster?

Yes. At MSK, we strongly encourage all of our patients to get vaccinated and boosted.

People who have cancer now or who have had cancer may have a weakened immune system because of the disease or its treatment. Because of this, they are particularly susceptible to severe COVID-19. These bivalent boosters provide another layer of protection beyond the primary vaccine shots and booster shots that you may have received.

What about people who are pregnant, expecting to become pregnant, or are breastfeeding? Can they get a bivalent booster shot? Should they?

Yes. People who are pregnant, expecting to become pregnant, or are breastfeeding are eligible to get a bivalent booster shot.

Can I still get the regular (monovalent) COVID-19 booster shot? What if I just completed my primary vaccine series?

No. When the FDA authorized these bivalent boosters, they also removed authorization for monovalent boosters.

If the bivalent booster provides better protection, can I get it as my primary shot?

No. The bivalent boosters have not been developed for that purpose yet. They are currently designed to be used as booster shots, meaning they have only been studied in previously vaccinated people.

I was infected with COVID-19 recently. Should I get the bivalent booster? When?

Yes, it’s recommended that people who have been infected with COVID-19 should still get the bivalent booster.

We know from past research that primary vaccination and booster doses after infection increase protection against future infection and severe disease. This applies to bivalent booster shots too.

People who were recently infected may choose to wait 3 months to receive their booster shot.

Can I get the bivalent booster at the same time as my flu vaccine?

Yes. All COVID-19 vaccines (including boosters) are safe and effective when given with other vaccines. There is no specific time interval that is recommended between routine vaccinations and the COVID-19 vaccine. The most important thing is that you take both vaccines. Whether it is on the same day or different days, that is your choice.

If vaccinated on the same day, it is recommended that the shots are given in different arms.

Should I get the same brand of bivalent booster as my other shots? Or can I mix and match between brands?

It is acceptable to mix and match if the booster is approved for your age group. You can switch brands again or stick with what you’ve received in the past.

I am eligible for the bivalent Omicron booster. When should I get it?

You should take the bivalent booster as soon as you can. The variants targeted by the bivalent booster (Omicron BA.4/5) are expected to continue to circulate throughout the U.S.

Can I get my bivalent booster shot at MSK? How do I schedule an appointment?

Adult patients can schedule their bivalent booster shot at MSK using this link »

For pediatric patients, you will need to call your child’s primary care doctor at MSK. A parent or guardian must be on-site to consent to their child getting the vaccine. They cannot give consent over the phone or electronically.

However, there is no need to wait to be vaccinated at MSK. We encourage patients to use the following websites to find a location with vaccine availability:

December 14, 2022

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