prophylactic immunization

例句：

1. 1. The doctor prescribed a prophylactic vaccine for her to protect againstthe flu.
   医生给她开了一种预防性的疫苗，以预防流感。
2. 2. Thecompany is implementing prophylactic measures to reduce employeeturnover.
   该公司正在实施预防性措施，以减少员工流失。
3. 3. Prophylactics are usedto prevent diseases before they occur.
   预防性药物用于在疾病发生前预防。