The measles, mumps and rubella vaccine is 97% effective, so why are we seeing so many outbreaks? CNN’s Chief Medical Correspondent Dr. Sanjay Gupta explains why the contagious disease is spreading.The measles, mumps and rubella vaccine is 97% effective, so why are we seeing so many outbreaks? CNN’s Chief Medical Correspondent Dr. Sanjay Gupta explains why the contagious disease is spreading.
