Children less than 15 years of age are principally affected. Most infections result in mild symptoms or no symptoms at all. About 30 percent of survivors will have serious neurological and psychiatric sequelae. There is no specific treatment for Japanese encephalitis. Care of patients focuses on treatment of symptoms and complications.
Vaccination is the single most important measure to control Japanese encephalitis.
The only vaccine that is commercially available on the international market is the mouse brain-derived inactivated vaccine. Recent work has been focused on developing and distributing newer vaccines that are more efficacious and with fewer side effects. Children over one year of age and adults can be vaccinated against Japanese encephalitis. No data exist about the safety and efficacy of the vaccine in infants less than one year of age. In endemic areas 2 doses are given 1-4 weeks apart, with a booster after 1 year and every 3 years after that, as needed.