Booster Shots of COVID-19 Vaccines Effective Against Omicron Subvariant

What you need to know

A small study supported by the National Cancer Institute found that booster doses of COVID-19 vaccines already in use produce neutralizing antibodies effective against a recent subvariant of the SARS-CoV-2 Omicron variant.

What did the researchers do?

Like all coronaviruses, SARS-CoV-2 — the virus that causes COVID-19 — has spike proteins on its surface that give it the ability to latch onto and infect cells. The Omicron variant of SARS-CoV-2 (BA.1) and its most common subvariant (BA.2) have spike proteins that are better at doing this than the original virus.

Vaccines against SARS-CoV-2 prompt the immune system to make neutralizing antibodies — Y-shaped proteins that bind to the virus and prevent it from infecting cells. Researchers wanted to know whether the vaccines available today stimulate enough antibodies to protect people from BA.2.

Researchers tested antibodies from the blood of 24 people after vaccination and booster doses of the Pfizer-BioNTech vaccine. They also looked at antibodies from eight people who had recovered from COVID-19, seven of whom had been vaccinated.

Participants who had a two-dose vaccination and received a booster shot had a high number of antibodies that could recognize BA.2 and BA.1. That number was even higher than the number of antibodies that could recognize the original SARS-CoV-2 after a two-dose vaccination.

People who received only the primary two-dose vaccination had far fewer neutralizing antibodies against BA.2 — 20 times lower than the number of antibodies that recognized the original SARS-CoV-2.

Why is this research important?

As of May 2022, the Omicron variant is the most dominant strain of SARS-CoV-2 in the world. According to the researchers, the results of this study indicate that the increase in COVID-19 cases from the BA.2 subvariant is more likely due to the virus being more easily spread among people than to its ability to evade our immune systems — which is good news. It gives researchers confidence that vaccines in use today are still effective at slowing the spread of the virus.

Previous research has already shown the importance of booster doses in protecting people from severe COVID-19, and these new findings add to that body of research.

Where can I go to learn more?

Antibodies recognize new SARS-CoV-2 Omicron variant after booster

• An article in NIH Research Matters explains the results of this study.

Understanding SARS-CoV-2 antibody binding

• A primer on how the virus that causes COVID-19 attaches to and enters cells.

Measuring protection after COVID-19 vaccination

• A description of how researchers are working to shorten the time it takes to test vaccines in the future.

Sources

Yu, J., Collier, A. Y., Rowe, M., Mardas, F., Ventura, J. D., Wan, H., Miller, J., Powers, O., Chung, B., Siamatu, M., Hachmann, N. P., Surve, N., Nampanya, F., Chandrashekar, A., & Barouch, D. H. (2022). Neutralization of the SARS-CoV-2 Omicron BA.1 and BA.2 variants. New England Journal of Medicine, 386, 1579–80. https://doi.org/10.1056/NEJMc2201849