title: A Japanese study to assess immunogenicity and safety of a typhoid Vi polysaccharide vaccine.
abstract: BACKGROUND
  Although typhoid fever is rare in Japan, imported cases have been reported occasionally in travelers returning from endemic areas. To achieve licensing of a typhoid Vi polysaccharide vaccine (Typhim Vi(®)) and make it widely available in Japan, this study was conducted at the request of the Japanese Ministry of Health Labor and Welfare to assess the immunogenicity and safety of this vaccine when given as a single dose (the recommended schedule of administration) in a Japanese population.
  
  
  METHODS
  In this multi-center, open-label, non-comparative, intervention study performed in Japan, 200 healthy volunteers (188 adults [≥ 18 years of age], 7 adolescents [12-17 years of age] and 5 children [2-11 years of age]) were administered Typhim Vi(®). Immunogenicity was assessed 28 days after vaccinations using an ELISA method of anti-Vi antibody detection. A 4-fold increase in anti-Vi titer was considered as the threshold for seroconversion for anti-Vi antibodies. Safety was assessed up to 28 days following vaccination.
  
  
  RESULTS
  Overall, 92.0% (95% confidence interval [CI]: 87.3-95.4%) of participants achieved seroconversion 28 days after a single dose of typhoid Vi polysaccharide vaccine. GMTs of Vi antibody titers increased from 6.6 (95% CI: 5.8-7.4) prior to vaccination to 157.3 (95% CI: 135.1-183.2) on Day 28 after vaccination. The geometric mean of individual anti-Vi antibody titer ratios (Day 28/Day 0) was 23.9 (95% CI: 20.3-28.3). There were no immediate adverse events and no adverse events led to the discontinuation of participants from the study. Across all age groups, pain and myalgia were the most frequently reported injection site and systemic reactions, respectively. Most of these reactions were mild in intensity and resolved within 7 days.
  
  
  CONCLUSIONS
  A single dose of typhoid Vi polysaccharide vaccine, Typhim Vi(®), demonstrated good safety and immunogenicity profile in a Japanese population.
authors.affiliation: Meitetsu Hospital, Sako, Nishi-ku, Nagoya-Shi, Aichi, Japan. Electronic address: mmiyazu@meitetsu-hpt.jp.
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Miyazu
authors.affiliation: Meitetsu Hospital, Sako, Nishi-ku, Nagoya-Shi, Aichi, Japan. Electronic address: hkikuchi@meitetsu-hpt.jp.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kikuchi
authors.affiliation: Tokyo Medical University Hospital, Nishi-Shinjuku, Shinjuku-Ku, Tokyo, Japan. Electronic address: a-hamada@tokyo-med.ac.jp.
authors.forename: Atsuo
authors.initials: A
authors.lastname: Hamada
authors.affiliation: Tokyo Medical University Hospital, Nishi-Shinjuku, Shinjuku-Ku, Tokyo, Japan. Electronic address: fuku789@tokyo-med.ac.jp.
authors.forename: Shinji
authors.initials: S
authors.lastname: Fukushima
authors.affiliation: Kawasaki Medical School, Matsushima 577, Kurashiki-Shi, Okayama, Japan. Electronic address: kouchi@med.kawasaki-m.ac.jp.
authors.forename: Kazunobu
authors.initials: K
authors.lastname: Ouchi
authors.affiliation: Sanofi Pasteur, Marcy l'Etoile, France. Electronic address: valerie.boschcastells@sanofipasteur.com.
authors.forename: Valerie
authors.initials: V
authors.lastname: Bosch Castells
authors.affiliation: Sanofi K.K., Tokyo, Japan. Electronic address: hanako.mihara@sanofi.com.
authors.forename: Hanako
authors.initials: H
authors.lastname: Mihara
authors.affiliation: Sanofi Pasteur, Marcy l'Etoile, France. Electronic address: marieclaudebonnet38@gmail.com.
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Bonnet
mesh_terms: D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood; D002648:Child; D002675:Child, Preschool; D064420:Drug-Related Side Effects and Adverse Reactions / Q000453:epidemiology / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D011135:Polysaccharides, Bacterial / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D016896:Treatment Outcome; D014435:Typhoid Fever / Q000517:prevention & control*; D014436:Typhoid-Paratyphoid Vaccines / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology*; D055815:Young Adult
chemical_list: D000907:Antibodies, Bacterial; D011135:Polysaccharides, Bacterial; D014436:Typhoid-Paratyphoid Vaccines; C057664:Vi polysaccharide vaccine, typhoid
keywords: Immunogenicity; Japan; Safety; Typhoid; Vaccine