[1] Snopes: Did Merriam-Webster Update Its Entry on ‘Sexual Preference’ After Barrett Hearing? https://archive.ph/dFEIk
[2] Of course, they say only changed it merely "after" she used it, not "because" of it. But come on...
Jan 18th, 2021: https://web.archive.org/web/20210118193104/https://www.merri...
> a preparation of killed microorganisms, living attenuated organisms, or living fully virulent organisms that is administered to produce or artificially increase immunity to a particular disease
Now:
> a preparation that is administered (as by injection) to stimulate the body's immune response against a specific infectious agent or disease
Macmillan [1]: someone who believes that vaccinations are harmful to human health and so refuses to vaccinate their children against childhood diseases
Lexico (Oxford) [2]: A person who is opposed to vaccination.
Cambridge [3]: someone who does not agree with vaccinating people (= giving them injections to prevent disease) and spreads and encourages opinions against vaccines
Wikitionary [4]: A person who opposes vaccination, as for its purported dangerous effects.
Dictionary.com [5]: a person who distrusts or is against vaccination, especially a parent who refuses to have a young child vaccinated.
American Heritage [6] and Longman [7]: It seems that they do not have an entry. Collins also doesn't have an entry, but apparently there was a suggestion for adding it in 2015. [8]
[1]: https://www.macmillandictionary.com/dictionary/british/anti-...
[2]: https://www.lexico.com/en/definition/anti-vaxxer
[3]: https://dictionary.cambridge.org/dictionary/english/antivaxx...
[4]: https://en.wiktionary.org/w/index.php?title=anti-vaxxer&oldi...
[5]: https://www.dictionary.com/browse/antivaxxer
[6]: https://www.ahdictionary.com/word/search.html?q=anti-vaxxer
[7]: https://www.ldoceonline.com/spellcheck/english/?q=anti-vaxxe...
[8]: https://www.collinsdictionary.com/submission/15399/Anti-Vaxx...