Japanese encephalitis (JE) is the leading viral cause of disability in Asia. The mosquitoes that transmit JE breed in areas of standing water, such as rice paddies, making rural communities of Asia particularly vulnerable. Immunization is the best method to prevent JE, but control efforts have been hindered by inadequate disease surveillance, limited/unstable vaccine supply, variable guidance and programmatic support, and competing country/state priorities. Over the past several years, focused efforts from PATH and other partners have improved the landscape of JE control across the country.In 2006, the government launched the Japanese Encephalitis Vaccine (JEV) campaign, rolling out a successful program within eight months. Over nine million children were able to receive JEV ahead of the JE season in India. This proved to be a landmark year for India’s rural population after decades of suffering from recurring JE outbreaks.This document details the phased JEV campaign across select endemic districts of Bihar, followed by the introduction of JEV in the routine immunization schedule and the lessons learned for strengthening immunization program all across.