ABSTRACT
Background: Japanese Encephalitis (JE) is common in the plains and mountainous areas in Asia \u2013 Pacific. Japanese encephalitis vaccine shows effectiveness in protecting children from JE in some countries such as Japan and Korea. Objective: To evaluate the efficacy of Japanese Encephalitis (JE) vaccination in Thai Binh province during 2003-2007. Subject and Method: Prospective, retrospective and sero-epidemiological methods were carried out on 329 samples collected from viral encephalitis patients and tested by JE MAC-ELISA, the positive average was 41.6% (137/329). Result: It had dramatically dropped from 85.2% in 2003 to 8.5 % in 2007 related to the rate of JE vaccination for children from 1 to 5 years old increasing from 49 % in 2003 to 77 % in 2007. Most of JE confirmed cases were un-vaccinated. Conclusion: JE etiology cause viral encephalitis in children in Thai Binh province was reduced thanks to JE vaccination in EPI program for 1 to 5 year old children. But more than 96% (131/136) of viral encephalitis in 15 years old upward was unknown etiology, the need for further study of the etiology cause viral encephalitis in adults.