im ‧ mu ‧ nize BrE AmE ( also immunise British English ) /ˈɪmjənaɪz, ˈɪmjʊnaɪz/ verb [transitive]
to protect someone from a particular illness by giving them a ↑ vaccine SYN vaccinate , inoculate
immunize somebody against something
There is still no vaccine to immunize people against the virus.
—immunization /ˌɪmjənaɪˈzeɪʃ ə n, ˌɪmjʊnaɪˈzeɪʃ ə n $ -nə-/ noun [uncountable and countable]