attenuated bacteria vaccine

例句：

1. 1.The vaccine was attenuated to be less harmful.
   该疫苗被制成了减轻其危害的版本。
2. 2. The bacteria in the vaccine were attenuated to survive in the human body.
   疫苗中的细菌被制成了可以在人体中存活的版本。
3. 3.The attenuated bacteria are used to treat infections.
   这种减毒细菌用于治疗感染。