/'væksi:n; [US] væk'si:n; væk`sin/
n [U, C] substance that is injected into the bloodstream and protects the body by making it have a mild form of the disease 疫苗; 菌苗
*develop a smallpox, polio, rabies, etc vaccine 培养天花、小儿麻痹症、狂犬病等的疫苗. Cf 参看 serum2.

n [U and C]
[Date: 1700-1800; Language: Latin;Origin: vaccinus 'of a cow', from vacca 'cow'; because the substance was originally obtained from sick cows]
a substance which contains a weak form of the bacteria or virus that causes a disease and is used to protect people from that disease
　a polio vaccine
　Doctors worried that there would not be enough vaccine for everyone who needed it.