Reported measles immunisation and serological immunity in children attending general practitioners

To determine the feasibility of serological testing for measles immunity in children attending general practitioners and to assess the validity of establishing immune status by reported immunisation history compared with serology, a cross-sectional descriptive study was conducted in general practices in the Illawarra area south of Sydney, New South Wales. Participants were 234 children under 15 years attending general practitioners. 87 per cent of children were reported to have been immunised against measles, but 46 per cent of these children were seronegative for measles antibody using an ELISA test on finger-prick blood. This could not be explained by inaccurate reporting of immunisation. No causes other than failure to seroconvert or inadequate specificity of the test on the blood samples were evident. Failure to seroconvert as a result of inadequate adherence to cold chain requirements is a possibility that needs further investigation. The results further question whether a single vaccination is adequate to achieve the public health aims of measles immunisation programs.