Progress and Innovation in Japanese Encephalitis Vaccines: Toward Global Immunization.

Abstract

Japanese encephalitis (JE) remains a major public health concern, especially in Asia and the Western Pacific, where more than 3 billion people are at risk. Despite advances in vaccine development, challenges such as viral strain diversity, limited crossprotection, and access barriers persist. JE directly impacts economic development because disease patterns are influenced by factors such as healthcare infrastructure, surveillance, vaccine availability, and agricultural trends across low-, middle-, upper-, and high-income countries. Current vaccines primarily target genotype III strains, but genotype I has become dominant in many endemic areas, raising concerns about vaccine efficacy. Furthermore, the need for booster doses, cold chain storage requirements, and high production costs all contribute to limited immunization coverage. Recent innovations, including thermostable formulations, multivalent vaccines, and mRNA-based candidates, offer promising solutions for JE prevention. Global initiatives by organizations such as WHO, GAVI, and PATH have played a critical role in increasing vaccine accessibility, yet gaps remain in achieving universal coverage. This review addresses the progress, challenges, and emerging strategies in JE vaccine development, emphasizing the importance of innovative approaches to ensure global protection against this life-threatening disease.