Immunogenicity of live attenuated Japanese encephalitis SA 14-14-2 vaccine among Sri Lankan children with previous receipt of inactivated JE vaccine. Issue 48 (21st November 2016)

• Record Type: Journal Article
• Authors: Wijesinghe, Pushpa Ranjan; Abeysinghe, M.R. Nihal; Yoksan, Sutee; Yao, Yafu; Zhou, Benli; Zhang, Lei; Fleming, Jessica A.; Marfin, Anthony A.; Victor, John C.
• Is Part Of: Vaccine. Volume 34:Issue 48(2016)
• Page Start: 5923
• Page End: 5928
• Publication Date: 2016-11-21
• Subjects: Japanese encephalitis vaccines -- Clinical trial -- Humoral immune response -- Secondary immune response -- Safety; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2016.10.028
• Languages: English
• ISSNs: 0264-410X

Abstract

Abstract: Background: The performance of live attenuated Japanese Encephalitis SA 14-14-2 vaccine (CD-JEV) among children previously given inactivated mouse brain-derived JE vaccine (IMBV) is unknown. We evaluated the safety and immunogenicity of CD-JEV administered to 2- and 5-year-old children in Sri Lanka. Methods: In this open-label, single arm trial in the Colombo District of Sri Lanka, generally healthy children 2 and 5 years of age who had previously received two and three doses of IMBV, respectively, were administered one dose of CD-JEV subcutaneously. Participants were monitored for adverse events for one year post-vaccination. Serum neutralizing antibody responses were evaluated pre and 28 and 365 days post-vaccination using JE plaque reduction neutralization test and characterized as the proportion of participants seroconverting. Seroconversion was defined as either reaching a titer considered seroprotective (⩾1:10) among participants with a baseline titer <1:10 or achieving at least a 4-fold rise in titer among participants with a baseline titer ⩾1:10. Results: Of 305 children given CD-JEV, 294 were included in the primary analysis of immunogenicity. Prior to vaccination, 144/147 (98.0%) 2-year-olds and 146/147 (99.3%) 5-year-olds had seroprotective levels. 28 days post-vaccination, 79/147 [53.7% (95% CI, 45.3–62.0)] 2-year olds and of 60/147 [40.8% (95% CI, 32.8–49.2)] 5-year olds achieved seroconversion. Among 2-year-olds, geometric mean titers (GMTs) rose from 697 to 3175 28 days post-vaccination. Among 5-year-olds, GMTs rose from 926 to 2776. Most adverse reactions were mild, and no serious adverse events were related to study vaccination. Conclusion: Administration of CD-JEV to these children with pre-existing neutralizing JE antibody titers was safe and resulted in substantial boosting of antibody levels. These results may inform other countries in Asia considering switching from IMBV to now WHO-prequalified CD-JEV vaccine to combat this disease of public health importance.