Abstract
Background
Health equity is a priority for India and numerous studies demonstrate that mean levels of vaccination coverage mask significant sub-national inequities, which persist for reasons linked with multiple socio-demographic, geographic, and supply-side barriers to access. Despite these multiple contributing dimensions, most inequity metrics only examine disparities along one dimension, such as wealth or urban/rural status, which may mask persistent disparities correlated with multiple dimensions. Our study utilizes the Vaccine Economics Research for Sustainability & Equity (VERSE) toolkit to compare measures of wealth-based inequity with a composite multivariate measure of inequity for fully-immunized status across 3 rounds of India’s National Family Health Survey (NFHS).
Methods
The VERSE tool produces a composite equity concentration index (CI) and absolute equity gap (AEG) based on this index, which, in its ranking procedure, accounts for multiple factors influencing equity in vaccination coverage, including maternal education level, sex of the child, household wealth, urban/rural designation, state of residence, and insurance coverage. To focus on inequities and not inequalities, age of the child is utilized to control for need by matching child age with the national immunization schedule recommendations. The VERSE equity tool is then applied to three rounds of India’s NFHS conducted between 2005-2021 to compare changes in the level of inequity in fully-immunized status that is captured using only a wealth-based CI vs. using the composite ranking criteria to generate a CI. For consistency across years, fully-immunized is defined as having received all recommended doses of BCG, DTP, Polio, and Measles vaccine appropriate for the current age of the child included in the NFHS, according to India’s national immunization schedule.
Results
Across the three rounds of the NFHS spanning 2006, 2016, and 2021 the wealth-based CI for fully-immunized status was 0.062, 0.042, and 0.021, respectively with a corresponding AEG of 41.1, 18.7, and 5.3 percentage points. Utilizing composite ranking, the CI for fully-immunized status was 0.273, 0.140, and 0.101, respectively with a corresponding AEG of 56.6, 37.1, and 22.1 percentage points. Over this same time period, fully-immunized coverage was 40.4, 54.1, and 47.9 percent, respectively.
Conclusion
While both composite and wealth-based CIs show improvement in inequities over time for India, wealth-based measures of inequity show a decline in the AEG between the poorest and richest quintiles of 87.1% (from 41.1 to 5.3 percentage points) between 2006 and 2021, while composite metrics indicate that this gap has only reduced by 61% (from 56.6 to 22.1 percentage points). The existing coverage gap in 2021 is approximately 4 times larger when measured utilizing composite ranking than when measured utilizing wealth alone (5.3 percentage points vs. 22.1 percentage points). As such, closing the coverage gap between the richest and poorest is unlikely to eliminate persistent socio-demographic inequities in vaccine coverage in India. The results suggest that pro-poor interventions and programs utilizing needs-based targeting based on poverty should consider expanding their targeting criteria to include other dimensions to reduce inequities. Additionally, a composite metric should be considered when setting targets and measuring progress toward reducing inequities in vaccination coverage.