title: Successful methodology for large-scale surveillance of severe events following influenza vaccination in Canada, 2011 and 2012.
abstract: In 2011 and 2012, a nationwide Canadian vaccine safety surveillance network rapidly collected safety data from healthcare workers (HCW) during the first weeks of the annual influenza vaccination campaign. This network provided the first available post-marketing safety data on seasonal influenza vaccines with information on background rates as a comparator. In 2012, these data were used to investigate a possible safety concern regarding a particular vaccine. An online questionnaire was provided to participating HCW two weeks before the annual influenza vaccination campaign for controls, and eight days after influenza vaccination for vaccinees. Control and vaccinees were requested to report health events occurring in the seven days prior to receiving the questionnaire. Control data were used to calculate background rates. HCW reporting a severe event were followed-up by telephone within 48 hours of the online report to validate the report and check on their health status. More than 22,000 vaccinated HCW were enrolled and surveyed over two seasons and > 90% reported no severe event following vaccination. Validated severe event rates were similar in vaccinated HCW and unvaccinated HCW (2.2% vs 2.3%; p < 0.70). The questionnaire was accurately completed for most reported symptoms, matched the validated report and was able to detect events of interest. Prior to the safety concern, the implicated vaccine was in use at one centre. Reassuring safety data were provided to public health authorities 48 hours after the vaccine was temporarily suspended. Data from this and similar networks can be used for rapid evaluation of vaccine safety and for safety assessment as required by the European Medicines Agency in 2015.
authors.affiliation: Vaccine Evaluation Center, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Bettinger
authors.forename: I
authors.initials: I
authors.lastname: Rouleau
authors.forename: M C
authors.initials: MC
authors.lastname: Gariepy
authors.forename: W R
authors.initials: WR
authors.lastname: Bowie
authors.forename: L
authors.initials: L
authors.lastname: Valiquette
authors.forename: O G
authors.initials: OG
authors.lastname: Vanderkooi
authors.forename: J D
authors.initials: JD
authors.lastname: Kellner
authors.forename: B L
authors.initials: BL
authors.lastname: Coleman
authors.forename: S A
authors.initials: SA
authors.lastname: McNeil
authors.forename: A
authors.initials: A
authors.lastname: McCarthy
authors.forename: G
authors.initials: G
authors.lastname: De Serres
mesh_terms: D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems; D000368:Aged; D002170:Canada / Q000453:epidemiology; D016022:Case-Control Studies; D062665:Epidemiological Monitoring; D005260:Female; D006282:Health Personnel; D006801:Humans; D007114:Immunization / Q000009:adverse effects*; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods*; D015397:Program Evaluation; D011795:Surveys and Questionnaires; D014611:Vaccination / Q000379:methods*
chemical_list: D007252:Influenza Vaccines