The impact of early-life access to oral polio vaccines on disability: evidence from India

Abstract

We evaluate the impact of oral polio vaccines on the incidence of all disabilities (locomotor, hearing, visual, speech, and mental) in India, focusing on polio-related disability, which constitutes the largest fraction of locomotor disabilities. Polio was hyperendemic in India even as recently as the early 1990s, but the country was declared wild polio virus-free in 2014. Intent-to-treat effects from difference-in-differences with multiple time period models that condition on demographic and socio-economic characteristics reveal that access to oral polio vaccines in the year of birth reduced the incidence of any disability, locomotor disability, and polio-related disability by 20.5%, 11.6%, and 7.2%, respectively, signaling substantial gains. Impacts on any disability underline that polio vaccines had positive spillover effects on other disability categories as well. The eradication of polio in India, while relatively late, brought significant health benefits and is a notable health economics success story in a developing context.