a substance which contains a form that is not harmful of a virus or bacterium (= extremely small organism ) and which is given to a person or animal to prevent them from getting the disease which the virus or bacterium causes
发音
例句
1. The polio vaccine has saved millions of lives. 脊髓灰质炎疫苗挽救了数以百万计的生命。 2. She takes a vaccine against influenza every fall. 她每年秋季接种流感疫苗。