它们可以产生足够多的新病毒来训练免疫系统杀死并记住它们，所以人们只需要接种一次疫苗。

They can produce enough new viruses to train the immune system to kill and remember them, so people only need to take the vaccine once.

youdao

这些卫生工作者在卫生、急救、免疫接种和其他基本的初级卫生保健服务上训练有素，成为应对任何紧急情况的医疗骨干。

These workers are trained in hygiene, first aid, immunization and other essential primary health care services and form the backbone of any emergency health response.

youdao

通过促进初级卫生保健的公平获取来提高卫生的可及性，特别是免疫接种、母亲和儿童健康以及在每一座村庄或城市地区配备一名训练有素的接生员；

increased access to health through promotion of equitable access to primary health care, in particular vaccination, mother and child health and one trained birth attendant per village or city quarter;

youdao

通过促进初级卫生保健的公平获取来提高卫生的可及性，特别是免疫接种、母亲和儿童健康以及在每一座村庄或城市地区配备一名训练有素的接生员；

increased access to health through promotion of equitable access to primary health care, in particular vaccination, mother and child health and one trained birth attendant per village or city quarter;

youdao