What does vax mean?
Vax is an informal English shortening of vaccine that became especially prominent during the COVID-19 pandemic. As a noun, it refers to a vaccine, most often a COVID-19 vaccine, and appears in conversational phrases involving getting, receiving, or receiving booster doses. As a verb, vax means to vaccinate someone or, intransitively, to receive a vaccine. The word is chiefly associated with American English, although it is now understood and used informally in many countries. Its tone is casual and direct rather than technical, making it especially common in news interviews, social media, and everyday discussions of vaccination. For formal medical or public-health writing, vaccine, vaccination, and vaccinate are normally preferred. Vax is also memorable because it compresses vaccine into a blunt, readily memorable nickname. It is not a separate technical medical term but an ordinary abbreviated form of vaccine, with plural vaxes used particularly in informal American English.
An informal term for a vaccine, especially a COVID-19 vaccine.
"She received her first booster vax at the local pharmacy."
Chiefly American and informal; the plural vaxes is common in the same register.
To vaccinate someone or, intransitively, to receive a vaccine.
"The rural clinic began to vax residents as soon as doses arrived."
Both vaxed and the spelling variant vaxxed are used; the verb is informal and chiefly American.
The plural is chiefly used in informal American English; vaccines remains the standard plural in formal usage.
"The two vaxes were administered an hour apart."
In a pandemic, “vax” turned “vaccine” into a household shorthand.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of vax
Vax is an early 21st-century informal alteration of vaccine that became widely established in American English around the beginning of the COVID-19 pandemic. Its ultimate linguistic root is Latin vacca, meaning “cow,” through the development of vaccinus and the English word vaccine. Related forms include vaccinate, vaccination, and vaccine.
Related word forms
How vax is actually used
The word is informal, chiefly associated with American English, and especially prominent in pandemic-related conversation. It can sound dismissive when used casually about vaccination, so formal medical and public-health contexts generally prefer vaccine, vaccination, and vaccinate.
Easily confused with vax
Vaccine is the standard, formal term for the preparation that provides immunity, whereas vax is its shorter, informal counterpart.