Income-Related Inequity in Child Immunization in India : Accounting for Horizontal and Vertical Inequity

India witnesses more than one million deaths of under-five children annually and two-third of all these deaths occur due to vaccine preventable diseases High share of incomplete immunization in India (WHO, 2022) leaves socioeconomically disadvantage group exposed to high morbidity and mortality risk factors. It demands comprehensive assessment of nature and extent of socioeconomic related inequity in child immunisation. Using the indirect standardisation method and Erreygers' corrected concentration index we first measured the degree of horizontal and vertical inequities, and then linearly decompose them to identify the major factors contributing towards the respective indices. We also adopt several strategies for robustness and sensitivity check on our findings. Our findings show that the incomplete immunisation is significantly concentrated among children belonging to poorer households. After controlling for the confounding effects of need factors, the inequity is still significantly pro-poor (indicating horizontal inequity). Its decomposition reveals that lower education, lower consumption and rural dwelling are the major factors driving the corresponding inequity. Further, the differential effect of needs between all and the target groups (at least based on education), is observed however is not significant enough to realise into inequity (indicating vertical equity). Hence, the direction and magnitude of vertical inequity is ambiguous but not significant. Overall, the inequity is being induced via non-need factors, but public health services (like Anganwadi) found to be the major reducing factor