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This fact brief was originally published as an experiment to test the concepts behind fact briefs.

Readers should be aware that while there is still a lot of useful information in fact briefs like this one, not all of them reflect Gigafact's current methods and standards for fact briefs. If you come across any that you feel are out of date, don't hesitate to contact us at support@gigafact.org.

FACT BRIEF

Does data show that the Pfizer COVID-19 vaccine’s protective effects last at least six months?

Monday, April 5, 2021

By Gus Fisher

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YES

The Pfizer-BioNTech COVID-19 vaccine remains highly effective against the disease for at least six months after the second dose, according to the developers’ April 2021 update of clinical trial results. Pfizer said their analysis found that for at least six months, the vaccine is 91.3% effective against all COVID-19 cases, and 100% effective against severe cases as defined by the Centers for Disease Control.

Experts are still learning more about exactly how long vaccines protect against COVID-19, the CDC reports—in part because the evidence can only accumulate as time goes by. A review of vaccine progress published in Nature observes that “only time will tell how long the vaccine-elicited protection will last, and how frequent the booster injections should be administered to keep the protection fully active.”

This fact brief is responsive to conversations such as this one.

Sources

Pfizer Pfizer and BioNTech update confirm efficacy and safety for up to six months following second COVID-19 vaccine dose

Centers for Disease Control Myths and facts about COVID-19 vaccines

UC Davis How the COVID-19 vaccine works, potential side effects and more

Nature COVID-19 vaccines: where we stand and challenges ahead

ABOUT THE CONTRIBUTOR

Gigafact

Between 2020 and 2022, under close editorial supervision, Gigafact contracted a group of freelance writers and editors to test the concepts for fact briefs and provide inputs to our software development process. We call this effort Gigafact Foundry. Over the course of these two years, Gigafact Foundry writers published over 1500 fact briefs in response to claims they found online. Their important work forms the basis of Gigafact formats and editorial guidelines, and is available to the public on Gigafact.org. Readers should be aware that while there is still a lot of relevant information to be found, not all fact briefs produced by Gigafact Foundry reflect Gigafact's current methods and standards for fact briefs. If you come across any that you feel are out of date and need to be looked at with fresh eyes, don't hesitate to contact us at support@gigafact.org.

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About fact briefs published on Gigafact

Fact briefs are short, credibly sourced summaries that offer “yes/no” answers in response to claims found online. They rely on publicly available, often primary source data and documents. Fact briefs are created by contributors to Gigafact —a nonprofit project looking to expand participation in fact-checking and protect the democratic process. See all fact briefs here.