Adverse events after Japanese encephalitis vaccination: review of post-marketing surveillance data from Japan and the United States

We determined the reporting rates for adverse events following the administ ration of inactivated mouse-brain derived Japanese encephalitis vaccine (JE V) based on post-marketing surveillance data from Japan and the United Stat es. The rate of total adverse events per 100,000 doses was 2.8 in Japan and 15.0 in the United States. In Japan, 17 neurological disorders were report ed from April 1996 to October 1998 for a rate of 0.2 per 100,000 doses. In the United States, no serious neurological adverse events temporally associ ated with JEV were reported from January 1993 to June 1999. Rates for syste mic hypersensitivity reactions were 0.8 and 6.3 per 100,000 doses in Japan and the United States, respectively. Passively collected VAERS surveillance data indicate that characteristic hypersensitivity reactions with a delaye d onset continue to occur among JEV recipients and that conservative recomm endations limiting its use to travelers at high risk of infection with Japa nese encephalitis are appropriate. Published by Elsevier Science Ltd.