A retrospective cohort study of risk factors for missing preschool booster immunisation.

AIM To identify factors associated with non-uptake of preschool booster immunisation. DESIGN Data from the computerised child health system was used to study all children born in 1990 and living in South Glamorgan, Wales, on their 5th birthday. Factors associated with preschool booster uptake were investigated using multiple logistic regression. RESULTS Preschool booster coverage in the study cohort was 91.4%. After adjustment for other variables, uptake was associated most strongly with completed primary immunisation for diphtheria, tetanus, and polio vaccine or first dose measles, mumps, and rubella vaccine. Identifying children who miss either of these predicts 52.4% of those who miss the preschool booster. CONCLUSION Effective targeting of children who have missed previous immunisations could improve preschool booster uptake and ensure maximum uptake of at least one dose of measles, mumps, and rubella vaccine. Achieving optimum measles vaccine coverage is vital to achieve the goal of measles elimination.