title: Human papillomavirus vaccine in boys: background rates of potential adverse events.
abstract: OBJECTIVE
  To determine background rates of potential adverse events following immunisation (AEFI) before expansion of the quadrivalent human papillomavirus (4vHPV) vaccination program to adolescent boys.
  
  
  METHODS
  Retrospective analysis of hospital discharge data obtained from the Victorian Admitted Episodes Dataset and emergency department visit data obtained from the Victorian Emergency Minimum Dataset for boys aged 12 to < 16 2013s during the period 1 July 2004 to 30 June 2009.
  
  
  METHODS
  Numbers of and incidence rates for Guillain-Barré syndrome, anaphylaxis, seizures, syncope and other potential AEFI from 1 July 2004 to 30 June 2009, and estimated numbers of events after 4vHPV vaccination assuming no association (other than temporal) with the vaccine.
  
  
  RESULTS
  We estimated background rates of neurological and allergic events in adolescent boys to be 252.9 and 175.2 per 100 000 person-2013s, respectively. Assuming an 80% vaccination rate with three doses per person - which equates to 1 440 000 doses administered nationally per 2013 in the first 2 2013s of the program - about 2.4 episodes of Guillain-Barré syndrome would be expected to occur in the 6 weeks following vaccination. Within 1 day of vaccination, about 3.9 seizures, 0.3 episodes of anaphylaxis and 6.5 acute allergy presentations would be expected.
  
  
  CONCLUSIONS
  Routinely collected health outcome administration data can inform postlicensure safety surveillance of target conditions that might be perceived as AEFI.
authors.affiliation: Surveillance of Adverse Events Following Vaccination in the Community SAEFVIC, Murdoch Childrens Research Institute, Melbourne, VIC. hazel.clothier@mcri.edu.au
authors.forename: Hazel J
authors.initials: HJ
authors.lastname: Clothier
authors.forename: Katherine J
authors.initials: KJ
authors.lastname: Lee
authors.forename: Vijaya
authors.initials: V
authors.lastname: Sundararajan
authors.forename: Jim P
authors.initials: JP
authors.lastname: Buttery
authors.forename: Nigel W
authors.initials: NW
authors.lastname: Crawford
mesh_terms: D000293:Adolescent; D002648:Child; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D015994:Incidence; D008297:Male; D009422:Nervous System Diseases / Q000453:epidemiology / Q000209:etiology*; D053918:Papillomavirus Vaccines / Q000009:adverse effects*; D012189:Retrospective Studies; D014739:Victoria / Q000453:epidemiology
chemical_list: D053918:Papillomavirus Vaccines