Measles is among the most infectious diseases of humans. Prior to the introduction of vaccination, virtually every child in the UK caught measles during two-yearly epidemics that each involved up to 700 000 reported cases. The illness presents with fever, coryza, cough and conjunctivitis before progressing to the classic rash after 2–4 days.1 Complications are more common in the very young and in adults and include otitis media, pneumonia, diarrhoea, keratitis and encephalitis. Although measles still kills around 150 000 children per year worldwide, in industrialised countries, case-fatality ratios are low with around one death for every 2000–5000 reported cases.1 ,2 The infection is most serious for individuals who are immunosuppressed, who may experience diffuse progressive pneumonitis or a delayed form of encephalitis, both associated with a high risk of death. For example, between 1974 and 1984, nearly one-third of deaths in British children in remission from leukaemia were measles related.3 The WHO aims to achieve measles elimination in at least five WHO regions by 2020, with the elimination target for the European region set at 2015.4

In the UK, measles vaccine was first introduced in 1968 for children in the second year of life. Although a single dose of measles vaccine provides between 90 and 95% protection,5–7 coverage remained low and measles continued to cause regular epidemics right up until the late 1980s. In 1988, the year that measles-mumps-rubella (MMR) vaccine was introduced, around 86 000 cases and 16 deaths were reported in England and Wales.8 Following the introduction of MMR, coverage improved to 92% and was sustained at this high level throughout the early 1990s. In November 1994, to prevent a predicted epidemic of measles amongst older children, combined measles-rubella vaccine was offered to all school children aged 5–16 years in a national vaccination campaign. …