Spontaneous reporting of adverse events following immunisation against pandemic influenza in Denmark November 2009-March 2010

Vaccine. 2011 Feb 1;29(6):1180-4. doi: 10.1016/j.vaccine.2010.12.008. Epub 2010 Dec 18.

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.

MeSH terms

  • Adolescent
  • Adult
  • Adverse Drug Reaction Reporting Systems
  • Aged
  • Aged, 80 and over
  • Child
  • Child, Preschool
  • Denmark
  • Female
  • Humans
  • Infant
  • Infant, Newborn
  • Influenza A Virus, H1N1 Subtype / immunology*
  • Influenza Vaccines / administration & dosage
  • Influenza Vaccines / adverse effects*
  • Influenza, Human / prevention & control*
  • Influenza, Human / virology
  • Male
  • Middle Aged
  • Pandemics / prevention & control*
  • Pregnancy
  • Young Adult

Substances

  • Influenza Vaccines