active immunization

例句：

1. 1.Active immunization is a crucial step in preventing the spread of disease.
   主动免疫接种是预防疾病传播的关键步骤。
2. 2.The vaccine was designed to provide active immunization against the virus.
   这种疫苗被设计用来提供对病毒的主动免疫。
3. 3.Active immunization has been shown to be effective in protecting against certain diseases.
   研究表明，主动免疫接种能有效预防某些疾病。