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Fact Check: Has Merriam-Webster’s Definition Of "Anti-Vaxxer" And "Vaccine" Changed?


Tom Hale

Tom is a writer in London with a Master's degree in Journalism whose editorial work covers anything from health and the environment to technology and archaeology.

Senior Journalist


The rephrased definitions are marginal, updated to reflect the latest science and COVID reality. Image credit: Anna Gawlik/

People on social media are claiming that Merriam-Webster, a leading publisher of dictionaries, has changed its definition of anti-vaxxer in an “Orwellian” fashion to now include those who oppose “regulations mandating vaccination.” While it's true its definition has slightly changed, this claim is misleading.

One recent Twitter post claims: “None of us were ‘anti-vaxxers’ until they literally changed the definition to include those who ‘oppose the use of... regulations mandating vaccination. The most Orwellian thing to happen during this pandemic is the real-time altering of definitions to gaslight the world.”


However, the change of definition was marginal, updated to reflect the COVID reality, not an "Orwellian" distortion of the truth. The current Merriam-Webster definition of “anti-vaxxer” is “a person who opposes the use of vaccines or regulations mandating vaccination.” Since at least 2018 it had read “laws mandating vaccination,” but it was changed in October 2021 from “laws” to “regulations.” 

In a statement to the Associated Press, Peter Sokolowski, Merriam-Webster editor-at-large, explained: “The reason for the change from ‘laws’ to ‘regulations’ is that overwhelming citational evidence shows that this term is used regarding vaccine policies for school districts, restaurants, concert venues, and bars, and that many of these policies are not laws.”

There have been many public health COVID measures issued by governments and public health authorities, but not all of them made it into law. 

There have also been claims that Merriam-Webster removed the immunity part of its “vaccine” definition. A Facebook post from November 2021 reads: “Vaccine used to be defined as a substance that provides 'immunity' to a specific disease. Now, Merriam Webster has literally changed the definition of 'vaccine' and removed the 'immunity' portion in order to possibly cover for the fact that the COVID 'vaccines' don't actually provide immunity from COVID."


The definition has indeed been rephrased but not removed. Merriam-Webster revised its definition of vaccine to replace "immunity" with "immune response". It now reads: "A preparation that is administered (as by injection) to stimulate the body's immune response against a specific infectious agent or disease."

Sokolowski explained to USA Today that the definition simply evolved to reflect how a vaccine scientifically works. This mirrors a similar alteration recently taken by the US Centers for Disease Control and Prevention (CDC), which changed its vaccine definition from “a product that stimulates a person’s immune system to produce immunity to a specific disease” to "a preparation that is used to stimulate the body’s immune response against diseases."

A CDC spokesperson told McClatchy News that they made this alteration because the old definition could have been “interpreted to mean that vaccines were 100 percent effective, which has never been the case for any vaccine, so the current definition is more transparent.”


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