COVID boosters might be needed as more research is done.
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Everything We Know About COVID-19 Vaccine Boosters So Far

If you’ve already been vaccinated, the booster is yet another question to consider.

Let’s take a second to acknowledge the positive: Americans now have three options, green-lit by the U.S. Food & Drug Administration (FDA), to become vaccinated against COVID-19. This news, and the subsequent distributions across the states, has provided hope and varying levels of relief, but our struggles with this life-altering virus are far from over. Parents are now wondering if teenagers should get the vaccine, what to do regarding the CDC mask guidelines and unvaccinated children, and how long a vaccine can actually offer protection. Will a booster be needed?

What Do We Know About COVID-19 Boosters So Far?

The idea of needing boosters or additional doses to remain resistant to COVID-19, or safeguard against possible new variants, is being discussed by the media, consumers, and company officials. Pfizer, one company behind a currently approved vaccine, shared on its website that in their studies of the Pfizer-BioNTech Covid-19 vaccine (BNT 162b2) in several hundred cases, it appeared effective for at least 6 months. And their research is ongoing into the possibility of using boosters to potentially renew protections or potentially offer protections from variants. Moderna, Inc. shared that the company is also studying the possibility of boosters for those already vaccinated and to address variants.

How Will We Know If We Need A COVID-19 Booster?

While multiple factors will go into determining whether or not boosters might offer more enduring protection, an uptick in “breakthrough infections in fully immunized persons” is a main one, says William Moss M.D., M.P.H., a professor at the Department of Epidemiology, International Health and Molecular Microbiology and Immunology at Johns Hopkins Bloomberg School of Public Health. “Particularly if these infections result in hospitalization or death. Measurement of waning neutralizing antibody levels in the laboratory would be supportive evidence.” Moss is also the executive director of International Vaccine Access Center.

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But it’s not just waning antibodies that are at stake. “Note that booster doses with the same vaccine, or additional doses with a modified vaccine, may be needed if a variant of concern emerges that can escape vaccine-induced immunity and result in hospitalization and death in fully immunized people,” Moss says.

While current available data isn’t showing that we need booster doses immediately, Moss says, recommendations on the matter would come from the Centers for Disease Control and Prevention, the Advisory Committee on Immunization Practices, and potentially the FDA. Might the determination to require a booster be impacted by, or differ depending on, which particular vaccination a person initially received? “Yes,” Moss says, “the need for booster doses may vary depending upon the type of vaccine a person received as the vaccines have different levels of effectiveness and the duration of immune protection may vary, although we do not know this yet.”

The bottom line? Yes, we have questions about boosters; yes, they might be a possibility in the future fight against COVID-19, and yes, the research is happening to learn more. Stay tuned.


William Moss M.D., M.P.H., professor, department of epidemiology, international health and molecular microbiology and immunology, Johns Hopkins Bloomberg School of Public Health. Executive director, International Vaccine Access Center.