title: Comparative study of adverse events after yellow fever vaccination between elderly and non-elderly travellers: questionnaire survey in Japan over a 1-year period.
abstract: BACKGROUND
  A live attenuated yellow fever (YF) vaccination is required of all travellers visiting countries where YF virus is endemic. Although the risk of serious adverse events (AEs) after YF vaccination is known to be greater in elderly people than in younger people, information about other AEs among elderly travellers is lacking.
  
  
  METHODS
  A prospective observational questionnaire study was conducted to investigate the occurrence of AEs after YF vaccination in travellers who attended a designated YF vaccination centre in Tokyo, Japan, from 1 November 2011 to 31 October 2012. A questionnaire enquiring about any AEs experienced in the 2 weeks following YF vaccination was distributed to all vaccinees enrolled in this study, and responses were collected subsequently by mail or phone. For child vaccinees, their parents were allowed to respond in their stead.
  
  
  RESULTS
  Of the 1298 vaccinees who received the YF vaccine, 1044 (80.4%) were enrolled in the present study and 666 (63.8%) responded to the questionnaire. Of these 666 respondents, 370 (55.6%) reported AEs, of which 258 (38.7%) were systemic and 230 (34.5%) were local. No severe AEs associated with YF vaccination were reported. Elderly vaccinees (aged ≥60 years) reported fewer total AEs than those aged <60 years (42.9% vs 60.3%;P < 0.001).
  
  
  CONCLUSIONS
  Our study showed that fewer general AEs after yellow vaccination reported among elderly vaccinees than among non-elderly vaccinees. These results could provide supplementary information for judging the adaptation of vaccination in elderly travellers.
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Tanizaki
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan infinite_u@hotmail.com.
authors.forename: Mugen
authors.initials: M
authors.lastname: Ujiie
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Narumi
authors.initials: N
authors.lastname: Hori
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Shuzo
authors.initials: S
authors.lastname: Kanagawa
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kutsuna
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Takeshita
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Kayoko
authors.initials: K
authors.lastname: Hayakawa
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kato
authors.affiliation: Disease Control and Prevention Center, National Center for Global Health and Medicine, Tokyo, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Ohmagari
mesh_terms: D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D007564:Japan; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D010290:Parents; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D014195:Travel; D015004:Yellow Fever / Q000517:prevention & control*; D022341:Yellow Fever Vaccine / Q000009:adverse effects*; D015005:Yellow fever virus
chemical_list: D022341:Yellow Fever Vaccine
keywords: Yellow fever; adverse event; elderly; questionnaire; traveller; vaccination