A significant part of the recent debate about measles and its resurgence has played out on social media. In particular, unfounded concerns about the safety of the MMR (measles, mumps and rubella) vaccine were amplified and spread this way. The scientific and public health communities are increasingly conscious of this phenomenon, as demonstrated, for example, by a recent paper in The Lancet. Various social media platforms, including Facebook and Twitter, have made efforts to block certain anti-vaccine content and display factually correct information about vaccines more prominently, but  significant problems and scope for improvement remain.