title: Side effects of influenza vaccination in healthy older people: a randomised single-blind placebo-controlled trial.
abstract: OBJECTIVE
  To investigate the frequency of side effects following influenza vaccination in healthy participants aged 65-74 years.
  
  
  METHODS
  A single-blind randomised placebo-controlled trial was performed in general practices in central Liverpool on 729 healthy individuals (341 females and 388 males) aged 65-74 (median age 68.9) years, of whom 552 received influenza vaccine and 177 received placebo. The main outcome measures were analysed from adverse reactions reported by the subjects on a postal questionnaire 3 days after vaccination.
  
  
  RESULTS
  724 (99.3%) questionnaires were returned. 62 (11.3%) participants who received influenza vaccination complained of local symptoms compared with 9 (5.1%) participants who received placebo (difference 6.2%; 95% CI 1.3 to 10.0%; p = 0.02). 192 (35.1%) individuals who received influenza vaccine complained of one or more systemic side effects compared with 75 (42.4%) who received placebo (difference -7.3%; 95% CI -15.6 to 0.9%; p = 0.10).
  
  
  CONCLUSIONS
  Healthy people belonging to this age group can be reassured that, when compared with placebo, influenza vaccination causes few, if any, systemic side effects and only a low incidence of local side effects.
authors.affiliation: Department of Geriatric Medicine, University of Liverpool, UK. flutrial@liv.ac.uk
authors.forename: S J
authors.initials: SJ
authors.lastname: Allsup
authors.forename: M
authors.initials: M
authors.lastname: Gosney
authors.forename: M
authors.initials: M
authors.lastname: Regan
authors.forename: A
authors.initials: A
authors.lastname: Haycox
authors.forename: S
authors.initials: S
authors.lastname: Fear
authors.forename: F C
authors.initials: FC
authors.lastname: Johnstone
mesh_terms: D000367:Age Factors; D000368:Aged; D016001:Confidence Intervals; D003362:Cost-Benefit Analysis; D005260:Female; D006801:Humans; D015994:Incidence; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000009:adverse effects* / Q000191:economics; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D011336:Probability; D012016:Reference Values; D018570:Risk Assessment; D017678:Sex Distribution; D012737:Sex Factors; D016037:Single-Blind Method; D006113:United Kingdom; D014611:Vaccination / Q000009:adverse effects* / Q000191:economics / Q000379:methods
chemical_list: D007252:Influenza Vaccines