INTRODUCTION: The Danish childhood vaccination programme offers protection against measles, mumps, and rubella (MMR). Nevertheless, many children appear to be unvaccinated according to the national registers. The aim of this study was to estimate the MMR1 vaccination coverage based on a medical record review of children whose vaccination status is negative according to the register-based data. METHODS: We conducted a cross-sectional study of 19 randomly selected general practices in the Central Denmark Region including 1,712 children aged 18-42 months. The practices received a registration form listing children with a negative MMR1 vaccination status in the register-based data. The general practices then validated the children's vaccination status by medical record review. RESULTS: In total, 94% of the children had been vaccinated according to the medical records in general practice compared with 86% according to the register-based data. Of the 246 children who were unvaccinated according to the register-based data, 135 (55%) had been vaccinated according to the medical records. This discrepancy was due mainly to administrative reimbursement errors. CONCLUSIONS: The MMR1 vaccination coverage in Denmark seems to be considerably higher than reflected in national registers. Using medical record review to re-assess the vaccination status revealed that most of the supposedly unvaccinated children had, in fact, been vaccinated. FUNDING: The Danish Research Foundation for General Practice and the General Practitioners' Foundation for Education and Development. TRIAL REGISTRATION: not relevant.
INTRODUCTION: The Danish childhood vaccination programme offers protection against measles, mumps, and rubella (MMR). Nevertheless, many children appear to be unvaccinated according to the national registers. The aim of this study was to estimate the MMR1 vaccination coverage based on a medical record review of children whose vaccination status is negative according to the register-based data. METHODS: We conducted a cross-sectional study of 19 randomly selected general practices in the Central Denmark Region including 1,712 children aged 18-42 months. The practices received a registration form listing children with a negative MMR1 vaccination status in the register-based data. The general practices then validated the children's vaccination status by medical record review. RESULTS: In total, 94% of the children had been vaccinated according to the medical records in general practice compared with 86% according to the register-based data. Of the 246 children who were unvaccinated according to the register-based data, 135 (55%) had been vaccinated according to the medical records. This discrepancy was due mainly to administrative reimbursement errors. CONCLUSIONS: The MMR1 vaccination coverage in Denmark seems to be considerably higher than reflected in national registers. Using medical record review to re-assess the vaccination status revealed that most of the supposedly unvaccinated children had, in fact, been vaccinated. FUNDING: The Danish Research Foundation for General Practice and the General Practitioners' Foundation for Education and Development. TRIAL REGISTRATION: not relevant.