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Influenza vaccine safety

Adverse reactions following vaccination

The European Medicines Agency (EMA) is evaluating, approving, and continuously monitoring the safety of vaccines in the European Union. The 2014 EMA Interim guidance on enhanced safety surveillance for seasonal influenza vaccines sets out specific criteria for annual enhanced safety surveillance to rapidly detect any increased local and systemic reactogenicity or other unexpected adverse immune response that may arise during the influenza vaccine product life-cycle [4].

Risks of an adverse event following influenza vaccination are far less common than complications related to influenza itself (Table 1), and the adverse events are generally localized and mild. Adverse reactions are more common in children not previously exposed to the vaccine or virus than in adults. The benefits of vaccination substantially outweigh the risks.

Table 1: Comparison of risks associated with influenza disease and inactivated seasonal influenza vaccination

Risks associated with seasonal influenza infectionRisks associated with inactivated seasonal influenza vaccination [1]

Common symptoms

  • Fever, sore throat, runny nose, dry cough, fatigue, headache, and muscle ache
  • Croup and bronchiolitis common in children

Common adverse event (<1/100)

  • Soreness/pain, redness and/or swelling around the injection site
  • Short-term fever (1–2 days), may be high (>39.0 C°) in children
  • Short-term fatigue (1–2 days)
  • Muscle ache (1–2 days)

Possible complications

  • Bacterial pneumonia
  • Ear infection
  • Sinus infection
  • Myocarditis
  • Pericarditis
  • Worsening of chronic medical condition present before influenza illness (e.g. congestive heart failure)
  • Precipitation of severe cardiovascular or cerebrovascular event

Rare adverse event (<1/1000)

  • Urticaria
  • Febrile convulsions in children

Rare complications

  • Septicaemia
  • Encephalopathy
  • Guillain-Barré syndrome [2]
  • Death

Very rare adverse event (<1/10.000)

  • Anaphylaxis
  • Paresthesia
  1. Reported risks refer to inactivated influenza vaccines commonly used in organised immunisation programmes in the European Union. For details see Summary of Product Characteristics for each vaccine available on national regulatory agency websites. The European Medicines Agency (EMA) disseminates vaccine safety information through its official website, assessment reports and press releases
  2. Julia Stowe, Nick Andrews, Lesley Wise, Elizabeth Miller Investigation of the Temporal Association of Guillain-Barré Syndrome With Influenza Vaccine and Influenza-like Illness Using the United Kingdom General Practice Research Database, American Journal of Epidemiology, Volume 169, Issue 3, 1 February 2009, Pages 382–388
Page last updated 27 Mar 2024