title: General practice encounters following seasonal influenza vaccination as a proxy measure of early-onset adverse events.
abstract: BACKGROUND
  In 2010, use of seasonal trivalent influenza vaccine (TIV) in children <5 years of age was suspended in Australia following reports of vaccine-related febrile convulsions. We investigated the utility of data on primary care [general practice (GP)] consultations for any reason within three days of receipt of influenza vaccine as recorded on the Australian Childhood Immunisation Register (ACIR) as a means of signal detection.
  
  
  METHODS
  Data on GP consultations were obtained from Medicare Australia (Australian Government Department of Human Services) for children recorded on the ACIR as receiving either TIV or monovalent influenza vaccine. Rates of GP consultation by day following ACIR-recorded receipt of influenza vaccine were compared by year (2008-2010), vaccine type, age and region.
  
  
  RESULTS
  In 2010, GP encounter rates on the day after receipt of the TIV manufactured by bioCSL (formerly CSL Biotherapies (Fluvax(®)) were significantly higher than both bioCSL TIVs in the previous two years [rate ratio (RR) 1.9; 95% CI: 1.7-2.2] and Sanofi Pasteur TIV, Vaxigrip(®) [RR 1.6, 95% CI 1.4-1.7] in 2009-2010. Encounter rates were also higher than for CSL Monovalent influenza vaccine, Panvax(®) [RR 1.9, 95% CI 1.7-2.2] in 2009-2010. These findings were robust to adjustment for age group (≤ 2, >2 years) and region (Western Australia vs other Australian states/territories).
  
  
  CONCLUSIONS
  A primary care consultation on the day after vaccine receipt is a reasonable proxy for early reactogenicity and has potential for use in various settings.
authors.affiliation: National Centre for Immunisation Research and Surveillance, Sydney, NSW, Australia; Discipline of Paediatrics and Child Health, University of Sydney, Sydney, NSW, Australia. Electronic address: aditi.dey@health.nsw.gov.au.
authors.forename: A
authors.initials: A
authors.lastname: Dey
authors.affiliation: National Centre for Immunisation Research and Surveillance, Sydney, NSW, Australia; School of Public Health and Community Medicine, University of New South Wales, Sydney, NSW, Australia.
authors.forename: H F
authors.initials: HF
authors.lastname: Gidding
authors.affiliation: National Centre for Immunisation Research and Surveillance, Sydney, NSW, Australia; Discipline of Paediatrics and Child Health, University of Sydney, Sydney, NSW, Australia.
authors.forename: R
authors.initials: R
authors.lastname: Menzies
authors.affiliation: National Centre for Immunisation Research and Surveillance, Sydney, NSW, Australia; Discipline of Paediatrics and Child Health, University of Sydney, Sydney, NSW, Australia; School of Public Health, University of Sydney, Sydney, NSW, Australia; The Children's Hospital at Westmead, Sydney, NSW, Australia.
authors.forename: P
authors.initials: P
authors.lastname: McIntyre
mesh_terms: D016907:Adverse Drug Reaction Reporting Systems / Q000706:statistics & numerical data*; D001315:Australia / Q000453:epidemiology; D002675:Child, Preschool; D064420:Drug-Related Side Effects and Adverse Reactions / Q000175:diagnosis / Q000453:epidemiology*; D058006:General Practice / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D007252:Influenza Vaccines / Q000009:adverse effects*; D011320:Primary Health Care; D003294:Seizures, Febrile / Q000139:chemically induced; D014611:Vaccination / Q000009:adverse effects*; D015164:Vaccines, Inactivated / Q000009:adverse effects
chemical_list: D007252:Influenza Vaccines; D015164:Vaccines, Inactivated; C551358:panvax; C478242:vaxigrip
keywords: Adverse events; General practice; Influenza; Primary care