Antibody persistence upto 5 years after primary immunization and booster with an inactivated chromatographically purified Vero cell-derived Japanese encephalitis vaccine in Thai children

• Published in: Human vaccines & immunotherapeutics Vol. 18; no. 1; p. 2028513
• Main Authors: Hattasingh, Weerawan, Chanthavanich, Pornthep, Sirivichayakul, Chukiat, Arunsodsai, Watcharee, Surangsrirat, Surachai, Srisuwannaporn, Termsang, Kaewma, Benjawan, Yoksan, Sutee, Limkittikul, Kriengsak, Yang, Junwei, Mao, Yu
• Format: Journal Article
• Language: English
• Published: United States Taylor & Francis 31.12.2022; Taylor & Francis Group
• Subjects: Animals; Antibodies, Viral; Antigens, Viral; Child; Children; Chlorocebus aethiops; chromatographical purify; Encephalitis, Japanese - prevention & control; Humans; immunogenicity; inactivated Vero cell-derived vaccine; Japanese encephalitis vaccine; Japanese Encephalitis Vaccines - adverse effects; Licensed Vaccines – Research Paper; long-term follow-up; Thailand; Vero Cells; Thailand; inactivated Vero cell-derived vaccine; Japanese encephalitis vaccine; Children; long-term follow-up; chromatographical purify; immunogenicity
• ISSN: 2164-5515; 2164-554X; 2164-554X
• DOI: 10.1080/21645515.2022.2028513

Japanese encephalitis is the main cause of viral encephalitis in Asia. In a previous single-arm vaccine trial, an inactivated chromatographically purified Japanese encephalitis Vero cell vaccine (CVI-JE; JEVAC TM ) was safe and immunogenic in 152 Thai children aged 1-3 years receiving a 2-dose primary immunization and booster dose 1 year later. We conducted a 5-year follow-up assessment of the persistence of the immune response the 144 children remaining in this cohort after first booster dose. Immunity was assessed by 50% plaque reduction neutralization test annually for up to 5 years post-booster. Seroprotection rates (95%CI) decreased from 100% (97.1-100) at 1 year post-booster to 93% (85.0-98.3) at 5 years post-booster. No serious vaccine-related adverse events or Japanese encephalitis infections were reported. A 2-dose primary immunization and booster 1 year later with CVI-JE provided long-lasting immunity in the majority of children.