title: Memory immune response and safety of a booster dose of Japanese encephalitis chimeric virus vaccine (JE-CV) in JE-CV-primed children.
abstract: Japanese encephalitis chimeric virus vaccine (JE-CV) is a licensed vaccine indicated in a single dose administration for primary immunization. This controlled phase III comparative trial enrolled children aged 36-42 mo in the Philippines. 345 children who had received one dose of JE-CV in a study two years earlier, received a JE-CV booster dose. 105 JE-vaccine-naïve children in general good health were randomized to receive JE-CV (JE-vaccine naïve group; 46 children) or varicella vaccine (safety control group; 59 children). JE neutralizing antibody titers were assessed using PRNT50. Immunological memory was observed in children who had received the primary dose of JE-CV before. Seven days after the JE-CV booster dose administration, 96.2% and 66.8% of children were seroprotected and had seroconverted, respectively, and the geometric mean titer (GMT) was 231 1/dil. Twenty-eight days after the JE-CV booster dose seroprotection and seroconversion were achieved in 100% and 95.3% of children, respectively, and the GMT was 2,242 1/dil. In contrast, only 15.4% of JE-CV-vaccine naïve children who had not received any prior JE vaccine were seroprotected seven days after they received JE-CV. One year after receiving the JE-CV booster dose, 99.4% of children remained seroprotected. We conclude that JE-CV is effective and safe, both as a single dose and when administrated as a booster dose. A booster dose increases the peak GMT above the peak level reached after primary immunization and the antibody persistence is maintained at least one year after the JE-CV booster dose administration. Five year follow up is ongoing.
authors: Sanofi Pasteur Clinical Development Department; Marcy l'Etoile, France.
authors: Emmanuel
authors: E
authors: Feroldi
authors: Maria Rosario
authors: MR
authors: Capeding
authors: Mark
authors: M
authors: Boaz
authors: Sophia
authors: S
authors: Gailhardou
authors: Claude
authors: C
authors: Meric
authors: Alain
authors: A
authors: Bouckenooghe
mesh_terms: D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D002675:Child, Preschool; D004672:Encephalitis, Japanese / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007117:Immunization, Secondary / Q000009:adverse effects / Q000379:methods*; D007156:Immunologic Memory; D022321:Japanese Encephalitis Vaccines / Q000008:administration & dosage* / Q000009:adverse effects / Q000276:immunology*; D008297:Male; D010679:Philippines
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D022321:Japanese Encephalitis Vaccines
keywords: Japanese encephalitis vaccines; active immunization; attenuated vaccines; booster immunization; humoral immune response