title: Spontaneous reporting of adverse events following immunisation against pandemic influenza in Denmark November 2009-March 2010.
abstract: Our study reviews the spontaneous reports of adverse events following immunisation submitted to the Danish Medicines Agency during the 2009-2010 influenza A/H1N1v season. During the study period (4 November 2009-31 March 2010), 607 reports comprising 1885 adverse events were reported among 339,507 influenza A/H1N1v vaccinated individuals (reporting rate, 179 per 100,000 vaccinated). The majority of individual case safety reports (85%) were submitted by physicians and other health care professionals and concerned known and non-serious reactions occurring within 1 day of vaccination (82%). Events of special interest as defined by EMA prior to vaccination campaign start, comprised 1% of all events. In conclusion, we did not observe any strong signals of any unknown or serious adverse events associated with influenza A/H1N1v vaccination in Denmark. Our experience also demonstrates the well-known limitations of spontaneous reports with respect to evaluation of a casual relationship and highlights the importance for a timely availability of background events rates and the need for new approaches to study late adverse effects following immunisation.
authors.affiliation: Danish Medicines Agency, Copenhagen, Denmark. mfolkenberg@gmail.com
authors.forename: Maja
authors.initials: M
authors.lastname: Folkenberg
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Callréus
authors.forename: Henrik
authors.initials: H
authors.lastname: Svanström
authors.forename: Palle
authors.initials: P
authors.lastname: Valentiner-Branth
authors.forename: Anders
authors.initials: A
authors.lastname: Hviid
mesh_terms: D000293:Adolescent; D000328:Adult; D016907:Adverse Drug Reaction Reporting Systems; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003718:Denmark; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000009:adverse effects*; D007251:Influenza, Human / Q000517:prevention & control* / Q000821:virology; D008297:Male; D008875:Middle Aged; D058873:Pandemics / Q000517:prevention & control*; D011247:Pregnancy; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines