The head of NHS England has warned that "vaccination deniers" are gaining traction on social media as part of a "fake news" movement. Simon Stevens said parents were seeing "fake messages" online about vaccines, which was making it harder to "win the public argument" on vaccination.
NHS England is considering what action can be taken to stop such messages spreading, Mr Stevens said. He said the health service needed to support parents on the issue.
Speaking at a health summit held by the Nuffield Trust think tank, Mr Stevens said that there had been a "steady decline" in the uptake of the measles vaccine over the last five years.
He went on to describe the uptake of the MMR vaccine among five-year-olds in England (87.5% compared with the World Health Organization target of 95%) as a "real problem".
Mr Stevens said parents at his daughter's primary school have expressed concern about vaccines. In January, the Royal Society for Public Health (RSPH) warned that social media is helping to spread "misleading and dangerous information" about vaccines.
Experts called for more to be done to challenge untruths about possible side effects of vaccines and said that social media giants should clamp down on "fake news".
The study said social media is a "breeding ground for misleading information and negative messaging around vaccination".