title: Immunogenicity of a Japanese encephalitis chimeric virus vaccine as a booster dose after primary vaccination with SA14-14-2 vaccine in Thai children.
abstract: Japanese Encephalitis chimeric virus vaccine (JE-CV) and SA14-14-2 vaccine are live-attenuated JE vaccines produced from the same virus strain. Data on interchangeability is limited.
  
  
  
  To evaluate the immunogenicity and safety of JE-CV booster after primary vaccination with SA14-14-2 vaccine.
  
  
  
  This study was an open-label clinical trial in Thai children who had received a primary SA14-14-2 vaccination at 12-24monthsbefore enrollment (ClinicalTrials.gov NCT02602652). JE-CV was administered. A 50% plaque reduction neutralization test (PRNT50) against three virus strains; JE-CV, SA-14-14-2andwild-type JE virus was measured before and 28-days post vaccination. The laboratory was performed at PRNT50titers ⩾10 (1/dil) were considered seroprotective against JE. Geometric mean titer (GMT) of PRNT50was calculated. Adverse events were observed for 28days.
  
  
  
  From March 2014 to June 2015, 50 children (64% male) were enrolled. Mean age and duration after primary vaccination was 26.9 (SD 4.6) and 12.8 (SD 2.7) months, respectively. The proportion of participants who had PRNT50pre and post-booster vaccination were 92% and 96% against JE-CV virus, 56% and 98% against SA-14-14-2 strain and 70% and 98% against wild-type JE virus, respectively. Solicited injection site reactions including erythema, pain and swelling occurred in 18%, 10% and 4% of subjects, respectively. Four children (8%) had fever (⩾37.7Celsius). Eight children (16%) had adverse events, which were not related to the vaccine.
  
  
  
  AJE-CV booster dose is highly immunogenic and safe among children who previously received SA14-14-2 vaccine.
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand.
authors.forename: Pakpoom
authors.initials: P
authors.lastname: Janewongwirot
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand; Research Unit in Pediatric Infectious Diseases and Vaccine, Chulalongkorn University, Bangkok, Thailand. Electronic address: thanyawee.p@chula.ac.th.
authors.forename: Thanyawee
authors.initials: T
authors.lastname: Puthanakit
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand; Research Unit in Pediatric Infectious Diseases and Vaccine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Suvaporn
authors.initials: S
authors.lastname: Anugulruengkitt
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand; Research Unit in Pediatric Infectious Diseases and Vaccine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Watsamon
authors.initials: W
authors.lastname: Jantarabenjakul
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand; Research Unit in Pediatric Infectious Diseases and Vaccine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Chayapa
authors.initials: C
authors.lastname: Phasomsap
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand; Research Unit in Pediatric Infectious Diseases and Vaccine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Sompong
authors.initials: S
authors.lastname: Chumket
authors.affiliation: Center for Vaccine Development, Institute of Molecular Biosciences, Mahidol University, Bangkok, Thailand.
authors.forename: Sutee
authors.initials: S
authors.lastname: Yoksan
authors.affiliation: Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine, Chulalongkorn University, Rama IV Road, Bangkok 10330, Thailand; Research Unit in Pediatric Infectious Diseases and Vaccine, Chulalongkorn University, Bangkok, Thailand.
authors.forename: Chitsanu
authors.initials: C
authors.lastname: Pancharoen
mesh_terms: D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood*; D002675:Child, Preschool; D004664:Encephalitis Virus, Japanese / Q000276:immunology*; D004672:Encephalitis, Japanese / Q000517:prevention & control*; D005260:Female; D005334:Fever / Q000209:etiology; D006801:Humans; D007117:Immunization, Secondary; D000071497:Immunogenicity, Vaccine; D007223:Infant; D000075662:Injection Site Reaction; D022321:Japanese Encephalitis Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000235:genetics / Q000276:immunology*; D008297:Male; D009500:Neutralization Tests; D013785:Thailand; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000009:adverse effects / Q000276:immunology
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D022321:Japanese Encephalitis Vaccines; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic
keywords: Children; Immunogenicity; Japanese encephalitis vaccine; Safety