Some advocacy groups have also expressed fears about the safety of the combined measles, mumps and rubella (MMR) vaccine, with some parents refusing to get their children vaccinated, officials say.

• 一些团体也开始对腮腺炎和风疹疫苗合用的安全性感到担心，官员称有的家长会拒绝给小孩打疫苗。