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English definition of “vaccine”

vaccine

noun [C or U] uk   /ˈvæk.siːn/ us  
C2 a substance containing a virus or bacterium in a form that is not harmful, given to a person or animal to prevent them from getting the disease that the virus or bacterium causes: This vaccine protects against some kinds of the bacteria.
(Definition of vaccine from the Cambridge Advanced Learners Dictionary & Thesaurus © Cambridge University Press)
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