MMR vaccine
The scientific consensus is that the MMR vaccine has no link to the development of autism, and that the vaccine's benefits greatly outweigh its risks. The false belief that the MMR vaccine causes autism led to a sharp drop in rates of vaccination in the UK and Ireland after 1998, creating a major public health risk. Lower vaccination rates were followed by increases in the incidence of measles and mumps, and the resulting cases of permanent disability and death.