Reasons for delayed compliance with the childhood vaccination schedule and some failings of computerised vaccination registers.

OBJECTIVE: To identify reasons for delay in completing the primary vaccination schedule.
METHOD: Brisbane, Queensland, 1995. Telephone interviews of a random sample of parents whose children according to a computerised database were fully vaccinated (100 parents) and parents whose children had commenced but not completed vaccination (200 parents).
RESULTS: The main reason for delaying vaccinations was medical advice to do so because of false contra-indications. The most significant factor in predicting timely vaccination, was the belief that giving vaccinations at the correct time was "very important", odds ratio 2.07 (95% CI 1.32-3.26). Eighty-six per cent of the children of interviewed parents from the group recorded as not fully vaccinated were in fact fully vaccinated.
CONCLUSIONS: The most important predictors of vaccination behaviour are the advice provided by medical practitioners and parental beliefs. Computerised vaccination records can seriously underestimate vaccination rates. IMPLICATIONS: Vaccination providers and the public need accurate knowledge about both the need for timely vaccination and the real contraindications to vaccination. For a vaccination register to record vaccination status with accuracy, service providers need to be highly co-operative in completing and returning vaccination records, and central data entry needs to be comprehensive and accurate.