Bridging the immunisation gap: socioeconomic and geographic drivers of pediatric immunisation disparities between different Indian states

Immunising children saves 2–3 million lives every year, making it one of the most effective public health interventions. India’s childhood immunisation rates are steadily improving, but there are still significant differences between states. Tamil Nadu consistently has one of the highest rates of child immunisation, while Nagaland is below the national average. If we figure out the socioeconomic factors that contribute to this difference, we can guide context-specific strategies to improve coverage. To compare the level and socioeconomic and geographic determinants of full immunisation coverage among children aged 12–23 months in Tamil Nadu and Nagaland using data from the fifth National Family Health Survey (NFHS-5, 2019-21). A survey-weighted cross-sectional analysis was performed on 1851 children (Tamil Nadu: 1291; Nagaland: 560). To be fully immunised, a child had to receive BCG, three doses of DPT, three doses of OPV, and one dose of MCV. Weighted bivariate chi-square tests and multivariable logistic regression models were used to assess associations between full Immunisation and socioeconomic, demographic, and geographic characteristics. We performed sensitivity analysis by restricting to only children who possessed vaccination cards, to assess the robustness of our findings. Immunisation coverage was higher in Tamil Nadu (89.2%) than in Nagaland (57.9%). In bivariate analysis, maternal education was significantly associated with full Immunisation in both states, while wealth, residence, distance to health facility, and birth order were additionally significant in Nagaland, and residence and religion in Tamil Nadu.In multivariable analysis, maternal education remained the most consistent predictor in Nagaland (AOR=2.61; p=0.003) and Tamil Nadu (AOR=2.32; p=0.029). In Nagaland, distance to health facility was also significant (p=0.034), whereas in Tamil Nadu, urban residence (AOR=1.83; p=0.008) and religion (AOR=4.00; p=0.003) were associated with Immunisation status. Other variables were not significant after adjustment. The main factors for the differences in immunisation coverage between states are gaps in maternal education and access to healthcare. To increase vaccination coverage in states with lower coverage, it is crucial to enhance women's education, extend outreach to rural populations, and address socioeconomic barriers.