The current low uptake of measles, mumps, and rubella (MMR) vaccine in some parts of the United Kingdom has led to well publicised concerns about the potential for measles outbreaks among primary school entrants. This has coincided with prepublication publicity last week of a paper casting doubts on the adequacy of the evidence which secured the licence for MMR vaccine.1 Understandably some parents and health professionals are confused and anxious and, in an effort to protect their children against measles, have sought single antigen vaccines. We have reviewed the latest developments in this saga and are convinced that such confusion and anxiety about MMR vaccine are unfounded. The authors of the paper, Wakefield and Montgomery, imply that they have examined all the safety data relating to the licensing of the vaccine1 in the early 1970s (1971 in US and 1972 in UK, not 1975 and 1988 as they say). Although this is their aim, in support of their concerns they also cite studies that postdate the award of licences. Therefore it is surprising that they do not mention the classical Finnish double blind placebo controlled trial among twins.2 This was a rigorous study which reported a low incidence of side effects, including gastrointestinal symptoms. The omission of this important study casts doubt on the completeness and impartiality of their review. The authors pay …