Safety and immunogenicity of a freeze-dried, cell culture-derived Japanese encephalitis vaccine (Inactivated) (JEBIK®V) in children

Freeze dried, cell culture-derived Japanese encephalitis vaccine (Inactivated) (JEBIK (c) V) is approved for a three-dose primary immunization followed by a one-dose booster immunization in Japan. We conducted a multicenter, double-blinded, randomized controlled trial of the safety and immunogenicity of the vaccine in 370 healthy children who received three doses of 5, 2.5 or 1.25 mu g of virus protein per 0.5 mL formulation subcutaneously. Children received two doses of test vaccine 7-28 days apart followed by a dose 6-12 months after the second vaccination. The three-dose regimen showed a good safety profile with no serious vaccine-related adverse events. Fever and reactions at the injection site were common adverse reactions at each dose of vaccine. The seroconversion rates were 100%, 99.2% and 95.0% after two doses in the 5, 2.5 and 1.25 mu g groups, respectively, and 100.0% after three doses in all groups. The geometric mean titers were high for all three formulations after the second and third doses, with a very clear dose-response relationship. These results indicate that JEBIK (c) V is likely to be a useful vaccine. (c) 2012 Elsevier Ltd. All rights reserved.