title: Pediatric anaphylactic adverse events following immunization in Victoria, Australia from 2007 to 2013.
abstract: BACKGROUND
  Anaphylaxis is a rare life-threatening adverse event following immunization (AEFI). Variability in presentation can make differentiation between anaphylaxis and other AEFI difficult. This study summarizes pediatric anaphylaxis AEFI reported to an Australian state-based passive surveillance system.
  
  
  METHODS
  All suspected and reported pediatric (<18 years) anaphylaxis AEFI notified to SAEFVIC (Surveillance of Adverse Events Following Vaccination In the Community) Melbourne, Australia, between May 2007 to May 2013 were analyzed. Clinical descriptions of the AEFI, using the internationally recognized Brighton Collaboration case definition (BCCD) and final outcome were documented.
  
  
  RESULTS
  93% (25/27) of AEFI classified as anaphylaxis met BCCD criteria, with 36% (9/25), assessed as the highest level of diagnostic certainty (Level 1). Median age was 4.7 years (range 0.3-16.2); 48% of cases were male. The vaccine antigens administered included: diphtheria, tetanus, acellular pertussis (DTaP) alone or in combination vaccines containing other antigens in 11 of 25 cases (44%); and live attenuated measles mumps rubella (MMR) vaccine for six (five also had other vaccines concomitantly administered). The estimated incidence rate of anaphylaxis for DTaP vaccines was 0.36 cases per 100,000 doses, and 1.25 per 100,000 doses for MMR vaccines. The majority of cases had rapid onset, but in 24% (6/25) of cases, first symptoms of anaphylaxis developed ≥30 min after immunization. In 60% (15/25) of cases, symptoms resolved ≤60 min of presentation. Intramuscular adrenaline was administered in 90% (18/25) of cases. All cases made a full recovery with no sequelae identified.
  
  
  CONCLUSIONS
  This comprehensive case series of pediatric anaphylaxis as an AEFI identified that diagnostic criteria are useful when applied to a passive vaccine surveillance system when adequate clinical information is available. Anaphylaxis as an AEFI is rare and usually begins within 30 min of vaccination. However, healthcare professionals and vaccinees/parents should be aware that onset of anaphylaxis can be delayed beyond 30 min following immunization and that medical attention should be sought promptly if anaphylaxis is suspected.
authors.affiliation: Department of General Medicine, The Royal Children's Hospital, Melbourne, VIC, Australia; Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA. Electronic address: daryl.cheng@rch.org.au.
authors.forename: Daryl R
authors.initials: DR
authors.lastname: Cheng
authors.affiliation: Department of General Medicine, The Royal Children's Hospital, Melbourne, VIC, Australia; Vaccine and Immunisation Research Group (VIRGo), Murdoch Childrens Research Institute and Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia; Department of Allergy and Immunology, Royal Children's Hospital, Melbourne, VIC, Australia.
authors.forename: Kirsten P
authors.initials: KP
authors.lastname: Perrett
authors.affiliation: Department of Allergy and Immunology, Royal Children's Hospital, Melbourne, VIC, Australia.
authors.forename: Sharon
authors.initials: S
authors.lastname: Choo
authors.affiliation: Department of General Medicine, The Royal Children's Hospital, Melbourne, VIC, Australia; Vaccine and Immunisation Research Group (VIRGo), Murdoch Childrens Research Institute and Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, VIC, Australia; Department of Pediatrics, The University of Melbourne, Melbourne, VIC, Australia.
authors.forename: Margie
authors.initials: M
authors.lastname: Danchin
authors.affiliation: SAEFVIC, Murdoch Children's Research Institute, Melbourne, VIC, Australia.
authors.forename: Jim P
authors.initials: JP
authors.lastname: Buttery
authors.affiliation: Department of General Medicine, The Royal Children's Hospital, Melbourne, VIC, Australia; Department of Pediatrics, The University of Melbourne, Melbourne, VIC, Australia; SAEFVIC, Murdoch Children's Research Institute, Melbourne, VIC, Australia.
authors.forename: Nigel W
authors.initials: NW
authors.lastname: Crawford
mesh_terms: D000293:Adolescent; D016907:Adverse Drug Reaction Reporting Systems; D000707:Anaphylaxis / Q000175:diagnosis / Q000209:etiology*; D001315:Australia / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004168:Diphtheria Toxoid / Q000008:administration & dosage / Q000009:adverse effects*; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D022542:Measles-Mumps-Rubella Vaccine / Q000008:administration & dosage / Q000009:adverse effects*; D010567:Pertussis Vaccine / Q000009:adverse effects*; D062486:Public Health Surveillance; D013745:Tetanus Toxoid / Q000008:administration & dosage / Q000009:adverse effects*; D013997:Time Factors; D014611:Vaccination; D017778:Vaccines, Combined / Q000008:administration & dosage / Q000009:adverse effects; D014739:Victoria / Q000453:epidemiology
chemical_list: D004168:Diphtheria Toxoid; D022542:Measles-Mumps-Rubella Vaccine; D010567:Pertussis Vaccine; D013745:Tetanus Toxoid; D017778:Vaccines, Combined; D004837:Epinephrine
keywords: AEFI; Anaphylaxis; Immunization; Vaccine safety