Coverage of childhood vaccination among children aged 12-23 months, Tamil Nadu, 2015, India.

BACKGROUND & OBJECTIVES: District-Level Household Survey-4 (DLHS-4) indicated that during 2012-2013, only 56 per cent of children aged 12-23 months in Tamil Nadu were fully vaccinated, which were lesser than those reported in earlier national surveys. We, therefore, conducted cluster surveys to estimate coverage of childhood vaccination in the State, and also to identify the factors associated with low coverage.

METHODS: Cross-sectional surveys were conducted in 15 strata [municipal corporation non-slum (n=1), municipal corporation slum (n=1), hilly (n=1), rural (n=6) and urban (n=6)]. From each stratum, 30 clusters were selected using probability proportional to the population size linear systematic sampling; seven children aged 12-23 months were selected from each cluster and their mothers/care-takers were interviewed to collect information about vaccination status of the child. A child was considered fully vaccinated if he/she received bacillus Calmette-Guérin (BCG), three doses of pentavalent, three doses of oral polio vaccine and one dose of measles vaccine, and appropriately vaccinated if all vaccine doses were given at right age and with right interval. Further, coverage of fully vaccinated children (FVC) as per vaccination cards or mothers' recall, validated coverage of FVC (V-FVC) among those having cards, and coverage of appropriately vaccinated children (AVC) were estimated using survey data analysis module with appropriate sampling weights.

RESULTS: A total of 3150 children were surveyed, of them 2528 (80.3%) had vaccination card. The weighted coverage of FVC, V-FVC and AVC in the State was 79.9 per cent [95% confidence interval (CI): 78.2-81.5], 78.8 per cent (95% CI: 76.9-80.5) and 69.7 per cent (95% CI: 67.7-71.7), respectively. The coverage of individual vaccine ranged between 84 per cent (measles) and 99.8 per cent (BCG). About 12 per cent V-FVC were not vaccinated as per the vaccination schedule.

INTERPRETATION & CONCLUSIONS: The coverage of FVC in Tamil Nadu was high, with about 80 per cent children completing primary vaccination. Efforts to increase vaccination coverage in the State need to focus on educating vaccinators about the need to adhere to the national vaccination schedule and strengthening supervision to ensure that children are vaccinated appropriately.