Analysis of the universal immunization programme and introduction of a rotavirus vaccine in India with IndiaSim

India has the highest under-five death toll globally, approximately 20% of which is attributed to vaccine-preventable diseases. India's Universal Immunization Programme (UIP) is working both to increase immunization coverage and to introduce new vaccines. Here, we analyze the disease and financial burden alleviated across India's population (by wealth quintile, rural or urban area, and state) through increasing vaccination rates and introducing a rotavirus vaccine. We use IndiaSim, a simulated agent-based model (ABM) of the Indian population (including socio-economic characteristics and immunization status) and the health system to model three interventions. In the first intervention, a rotavirus vaccine is introduced at the current DPT3 immunization coverage level in India. In the second intervention, coverage of three doses of rotavirus and DPT and one dose of the measles vaccine are increased to 90% randomly across the population. In the third, we evaluate an increase in immunization coverage to 90% through targeted increases in rural and urban regions (across all states) that are below that level at baseline. For each intervention, we evaluate the disease and financial burden alleviated, costs incurred, and the cost per disability-adjusted life-year (DALY) averted. Baseline immunization coverage is low and has a large variance across population segments and regions. Targeting specific regions can approximately equate the rural and urban immunization rates. Introducing a rotavirus vaccine at the current DPT3 level (intervention one) averts 34.7 (95% uncertainty range [UR], 31.7–37.7) deaths and $215,569 (95% UR, $207,846–$223,292) out-of-pocket (OOP) expenditure per 100,000 under-five children. Increasing all immunization rates to 90% (intervention two) averts an additional 22.1 (95% UR, 18.6–25.7) deaths and $45,914 (95% UR, $37,909–$53,920) OOP expenditure. Scaling up immunization by targeting regions with low coverage (intervention three) averts a slightly higher number of deaths and OOP expenditure. The reduced burden of rotavirus diarrhea is the primary driver of the estimated health and economic benefits in all intervention scenarios. All three interventions are cost saving. Improving immunization coverage and the introduction of a rotavirus vaccine significantly alleviates disease and financial burden in Indian households. Population subgroups or regions with low existing immunization coverage benefit the most from the intervention. Increasing coverage by targeting those subgroups alleviates the burden more than simply increasing coverage in the population at large