What does vaccine mean?
A vaccine is a medical preparation that teaches or prompts the immune system to recognize and defend against a particular pathogen, such as a virus or bacterium. Vaccines may contain weakened or inactivated organisms, subunits or antigens, genetic instructions, or another suitable biological material. In everyday use, the singular “a vaccine” and plural “vaccines” refer to these preparations, while “vaccination” usually describes the process of administering one. The word can also function as a verb: “to vaccinate” means to give someone a vaccine. Vaccine language is especially prominent in medicine, public health, science reporting, and discussions of personal choice and access. Its history is closely connected with cowpox and the work of Edward Jenner, who demonstrated that material from cowpox could protect against smallpox. Today, vaccines are developed for diseases ranging from seasonal influenza to polio, measles, and COVID-19.
A biological preparation that stimulates the immune system to develop protection against a specific disease or pathogen.
"The vaccine was tested in a large clinical trial before being approved for widespread use."
Usually countable, although collective expressions such as “the vaccine” are common in public-health discussion.
To administer a vaccine to someone in order to provide or promote immunity against a disease.
"Clinicians vaccinated more than ten thousand people during the campaign."
Often used in the passive form “to be vaccinated,” especially when referring to people receiving vaccination.
The standard plural is “vaccines.”
"The hospital received a new shipment of vaccines on Tuesday."
The word vaccine comes from Latin vacca, meaning “cow,” reflecting its origin in the use of cowpox to protect people against smallpox.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does vaccine come from?
The English word derives from the Latin adjective vaccinus, meaning “of or relating to cows,” from vacca, meaning “cow.” The term originally referred to cowpox and later developed into the general name for substances used to prevent infectious disease. Related English words include vaccinate, vaccination, vaccinator, and vaccinology.
Related word forms
How vaccine is actually used
In everyday public-health contexts, “vaccine” usually refers to a specific medical preparation, while “vaccination” refers to the procedure. The verb is common in formal and informal English, though “to administer a vaccine” may sound more formal.
Easily confused with vaccine
A vaccine is the preparation itself, whereas vaccination is the act or process of administering it.