Safety and immunogenicity of a freeze-dried, Vero cell culture-derived, inactivated Japanese encephalitis vaccine (KD-287, ENCEVAC®) versus a mouse brain-derived inactivated Japanese encephalitis vaccine in children: a phase III, multicenter, double-blinded, randomized trial
- Yun, Ki Wook; Lee, Hoan Jong; Kang, Jin Han; Eun, Byung Wook; Kim, Yae-Jean; Kim, Kyung-Hyo; Kim, Nam Hee; Hong, Young Jin; Kim, Dong Ho; Kim, Hwang Min; Cha, Sung-Ho
- Issue Date
- BioMed Central
- BMC Infectious Diseases. 15:7
- Background: Although mouse brain-derived, inactivated Japanese encephalitis vaccines (JE-MBs) have been successfully used for a long time, potential rare neurological complications have prompted the development of a Vero cell culture-derived inactivated vaccine (JE-VC). In a phase III clinical study, we aimed to compare the safety and immunogenicity of a JE-VC, KD-287 with a JE-MB, JEV-GCC, in children.
Methods: In this multicenter, double-blinded, randomized controlled trial, the study population consisted of 205 healthy Korean children aged 12–23 months. Each subject was subcutaneously vaccinated with either KD-287 or JEV-GCC twice at an interval of 2 weeks and then vaccinated once 12 months after the second vaccination. Neutralizing antibodies were measured by the plaque reduction neutralization test using the homologous and heterologous, as a post hoc analysis, challenge virus strains.
Results: The three-dose regimen of KD-287 showed a comparable safety profile with JEV-GCC except higher incidence of fever after the first dose (30.4% and 14.7%, respectively). Most of the fever was mild degree (61.3% and 66.7%, respectively). KD-287 fulfilled the non-inferiority criteria for seroconversion rate (SCR) and geometric mean titer (GMT) of the neutralizing antibody, which were the primary endpoints, at 4 weeks after the third vaccination (95% CI: −1.00, 3.10 for the SCR difference and 10.8, 17.6 for the GMT ratio). The SCRs of KD-287 were all 100% and the GMTs were higher in the KD-287 group than in the JEV-GCC group after the second vaccination and before and after the third vaccination (GMT ratio: 5.59, 20.13, and 13.79, respectively, p < 0.001 in all). GMTs were higher in the KD-287 group in the heterologous analysis also (GMT ratio: 4.05, 5.15, and 4.19, respectively, p < 0.001 in all).
Conclusions: This study suggests that the KD-287, a JE-VC is as safe as and may be more effective than the licensed MB-derived vaccine. KD-287 could thus be useful as a second-generation vaccine and substitute for the current JE-MB vaccine in Korean children.
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