Tolerability of Japanese encephalitis vaccine in pediatric patients

Background. Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus endemic to parts of Asia. Manufacture of JE-VAX, the mouse brain-derived vaccine against JEV, was discontinued in February 2011. IXIARO, an inactivated cell culture-derived vaccine, was approved in 2009 for use in adult patients. Although IXIARO was not licensed for pediatric patients until 2013, our clinic routinely used this vaccine in at-risk children starting in 2011. The purpose of this study was to review our experience as to the tolerability of the new IXIARO vaccine in children. Methods. We performed a retrospective chart review of all patients less than 18 years of age who received at least 1 dose of IXIARO in our Family Travel Clinic from November 2011 through August 2014. Subjects' electronic medical records were reviewed for any documented medical visits within 3 months after vaccination. Each visit was assessed for possible adverse events with relationship to vaccine administration as determined by the reviewer. Results. Ninety-two patients less than 18 years of age received a total of 145 doses of IXIARO between November 2011 and August 2014. Seven adverse events were documented. Only 1 was deemed to be possibly related. No serious adverse events were found on chart review. Conclusions. Our study reinforces the recent decision to expand IXIARO vaccination to the pediatric population. The experience in our clinic since vaccine introduction shows it to be overall tolerable when used in routine clinical practice. Practitioners should feel comfortable recommending vaccination against JEV for any pediatric traveler to an area of risk.