Immunisation against infectious disease has probably saved more lives than any other public health intervention, apart from the provision of clean water.1 Although other factors were important, it would not have been possible to eradicate smallpox without vaccination; the eradication of wild polio from the western hemisphere is largely due to immunisation; and the immense reductions in Haemophilus influenzae type b infections, diphtheria, whooping cough, and measles are also evidence of the value of immunisation.

Despite, or perhaps because of, the success of the immunisation programme in the United Kingdom a vocal minority of parents have cast doubt on the wisdom of having their children immunised, particularly with the measles, mumps, and rubella vaccine.2 Not only does this place their own children at risk, but if a significant number of children remain unimmunised it poses a risk to the general population.3 In this article we suggest how health professionals, particularly those within the primary healthcare team, can respond to parents' concerns.