preventive vaccine

• 预防用疫苗

preventive vaccine的用法和样例：

例句

1. Is there a human vaccine to protect from swine influenza?
   是否有人用疫苗来保护免于感染猪流感病毒？
2. The target of the vaccine is a hormone called ghrelin.
   用疫苗的话，是一种称为脑肠肽的激素。