What you need to know

SARS-CoV-2, the virus that causes COVID-19, is continuously evolving, producing new variants. Some of these variants are able to evade the protection offered by the original COVID-19 vaccines and boosters. In response, new vaccine boosters that target more than one variant of the virus were developed. These updated, bivalent boosters are meant to protect people against both the original strain of SARS-CoV-2 and Omicron variants.

In a study supported by the National Institute of Allergy and Infectious Diseases, a team of researchers found that the bivalent boosters were significantly more effective than the original boosters at preventing hospitalization and death from COVID-19.

What did the researchers do?

To understand how effective the bivalent vaccine boosters were against Omicron compared to the originals, researchers looked at data collected by the North Carolina Department of Health and Human Services when Omicron was the predominant variant of the virus.

Between May and August of 2022, 300,000 people in North Carolina received the original monovalent booster shot, and between September and December of 2022, more than 1 million people in North Carolina received the bivalent booster. The researchers compared the incidence of severe COVID-19 within those two groups. Severe COVID-19 was defined as hospitalization and/or death due to COVID-19 from 15 to 99 days after receiving a vaccine booster.

The research team found that the bivalent boosters were 62% effective at preventing severe COVID-19 infection. The monovalent boosters were only 25% effective. In total, the bivalent boosters were 37% more effective in preventing hospitalization and death.

Why is this research important?

This study presents clear evidence that bivalent boosters are more effective at preventing severe COVID-19 infection. Due to the vaccines’ safety and efficacy, the Centers for Disease Control and Prevention (CDC) recommends that everyone age 6 months and older receive their primary two-dose vaccination series and an updated bivalent booster to get maximum protection from severe COVID-19.

Where can I go to learn more?

Bivalent boosters provide better protection against severe COVID-19

• An article in NIH Research Matters shares additional information about this study.

Variants of the Virus

• CDC has more information on SARS-CoV-2 variants, including how they work and what steps CDC is taking to track them.

mRNA Vaccine Technology: A Promising Idea for Fighting HIV

• mRNA vaccine technology offers new hope for developing safe, effective vaccines to reduce the global toll of HIV/AIDS.

Sources

Lin, D-Y., Xu, Y., Gu, Y., Zeng, D., Wheeler, B., Young, H., Sunny, S. K., & Moore, Z. (2023). Effectiveness of bivalent boosters against severe omicron infection. New England Journal of Medicine, 388(8): 764–766. https://doi.org/10.1056/NEJMc2215471