Socioeconomic inequality trends in childhood vaccination coverage in India: Findings from multiple rounds of National Family Health Survey.

Objectives: This article examines the inequality patterns in childhood vaccination coverage at various socio-economic levels using all four rounds of nationally representative National Family Health Surveys (NFHS) in India.

Methods: The analytic sample restricted to the most recent singleton surviving children aged 12-23 months in each survey, was 11,599 in NFHS-1 (1992-93); 10,209 in NFHS-2 (1998-99); 9582 in NFHS-3 (2005-06) and 49,284 in NFHS-4 (2015-16). Complete childhood vaccination is defined as a child aged 12-23 months who received one dose of BCG (Bacille Calmette Guerin), one dose of measles, and three doses each of DPT (Diphtheria, Pertussis, Tetanus), and polio vaccine (excluding the polio vaccine given at birth) at any time before the survey-according to the vaccination card or the mother's recall. To understand inequalities in childhood vaccination, four measures were computed for each survey rounds' data-absolute measures of inequality, the slope index of inequality (SII), and two relative measures: the ratio between the extreme groups and the concentration index (CIX) to see the degree of disparity.

Results: The pro-rich and pro-education inequality in childhood vaccination coverage increased between 1998-99 and 2005-06 and declined considerably thereafter. This study found that inequality in childhood vaccination coverage has been minimized at a macro level such as rural-urban, male-female, religion, ethnicity, and in select geographies, but not universally at the micro-level. Findings indicate that pro-rich and pro-education inequalities were large among specific sub-groups of population: children in rural areas, children living in the northern region of the country and among scheduled tribes-as absolute and relative inequalities remained significantly high.

Conclusion: These findings recommend robust program monitoring and policy-level support at the micro level to optimize the use of existing resources across all segments of the population in the country.