____________________ America was declared free of measles 15 years ago, but health officials say increasing numbers of parents were declining for vaccination driven by fears of possible side effects. ___________________美国在15年前声称摆脱了麻疹,但是医疗官员表示越来越多的家长们因为担心可能会引起的副作用而拒绝为孩子接受免疫工作..
