title: Phase III clinical trials comparing the immunogenicity and safety of the vero cell-derived Japanese encephalitis vaccine Encevac with those of mouse brain-derived vaccine by using the Beijing-1 strain.
abstract: The immunogenicity and safety of an inactivated cell culture Japanese encephalitis vaccine (CC-JEV) were compared with those of an inactivated mouse brain-derived Japanese encephalitis vaccine (MB-JEV) in phase III clinical multicenter trials conducted in children. The vaccines contain the same Japanese encephalitis virus strain, the Beijing-1 strain. Two independent clinical trials (trials 1 and 2) were conducted. Trial 1 was conducted in 468 healthy children. Each subject was injected with 17 μg per dose of either CC-JEV or MB-JEV, and the immunogenicity and safety of the vaccines were investigated. Trial 1 showed that CC-JEV was more immunogenic and reactive than MB-JEV at the same dose. Therefore, to adjust the immunogenicity of CC-JEV to that of MB-JEV, a vaccine that has had a good track record regarding its efficacy for a long time, trial 2 was conducted in 484 healthy children. To improve the stability, CC-JEV was converted from a liquid type to a freeze-dried type of vaccine. Each subject was injected subcutaneously with either 4 μg per dose of CC-JEV, 8 μg per dose of CC-JEV, or 17 μg per dose of MB-JEV twice, at an interval of 2 to 4 weeks, followed by an additional booster immunization 1 to 15 months after the primary immunization. Based on the results of trial 2, 4 μg per dose of the freeze-dried CC-JEV (under the label Encevac) was selected as a substitute for the MB-JEV. Encevac was approved and launched in 2011 and has since been in use as a 2nd-generation Japanese encephalitis vaccine in Japan. (These studies have been registered at the JapicCTI under registration no. JapicCTI-132063 and JapicCTI-080586 for trials 1 and 2, respectively).
authors: Fukuoka-West Rehabilitation Center for Children, Fukuoka, Japan.
authors: Chiaki
authors: C
authors: Miyazaki
authors: Kenji
authors: K
authors: Okada
authors: Takao
authors: T
authors: Ozaki
authors: Mizuo
authors: M
authors: Hirose
authors: Kaneshige
authors: K
authors: Iribe
authors: Hiroyuki
authors: H
authors: Yokote
authors: Yuji
authors: Y
authors: Ishikawa
authors: Takehiro
authors: T
authors: Togashi
authors: Kohji
authors: K
authors: Ueda
mesh_terms: D000818:Animals; D002648:Child; D002675:Child, Preschool; D004672:Encephalitis, Japanese / Q000517:prevention & control*; D006801:Humans; D007223:Infant; D022321:Japanese Encephalitis Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology* / Q000302:isolation & purification; D051379:Mice; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology / Q000302:isolation & purification; D014709:Vero Cells
chemical_list: D022321:Japanese Encephalitis Vaccines; D015164:Vaccines, Inactivated