VOA慢速英语:联合国警告新冠疫情期间儿童疫苗接种量惊人下降

alarming – adj. something that is worrisome or dangerous

routine – adj. a common or usual activity

immunity – n. to be vaccinated against a disease

pandemic – n. a contagious disease that moves from one country to another

immunize – v. to vaccinate someone against a disease

challenge - n. something that is difficult to do