title: The effect of influenza vaccination on the incidence of chronic obstructive pulmonary disease exacerbations in the immediate postvaccination period.
abstract: BACKGROUND
  Influenza vaccination is an important strategy in the prevention of exacerbations in patients with chronic obstructive pulmonary disease (COPD). Despite the proven benefits, there are patients who are reluctant to have this intervention for fear of triggering an exacerbation. There are very few studies looking at the effect of the vaccination on exacerbation rates of COPD in primary care.
  
  
  METHODS
  Medical records were obtained from six primary care practices in the Derbyshire area (UK), and 293 pairs of patients were selected. All patients had a diagnosis of COPD based on post bronchodilator spirometry. Patients were matched according to age, sex, severity of COPD and comorbidities. The first group of patients received the influenza vaccination while the other group served as a control (either never received the vaccination or received it at a later date). The incidence of COPD exacerbations of both groups was recorded.
  
  
  RESULTS
  There were 21 exacerbations in the control group compared to 11 in the vaccinated group. The difference in exacerbation rates between groups was not statistically significant (McNemar's p=0.11). In the 2 weeks after receiving the influenza vaccination, the risk of experiencing an exacerbation in this group of patients was 0.52 in the vaccinated group compared to the non-vaccinated group (OR 0.52, CI 0.29 to 1.14).
  
  
  CONCLUSIONS
  Patients with COPD should be reassured that the influenza vaccination is safe and does not cause an increase in exacerbations. They should be encouraged to take up the vaccination annually before the onset of winter.
authors.affiliation: Chesterfield Royal Hospital NHS Foundation Trust, Chesterfield, Derbyshire, UK. s.ting@nhs.net
authors.forename: S C H
authors.initials: SC
authors.lastname: Ting
authors.forename: S W
authors.initials: SW
authors.lastname: Crooks
authors.forename: G
authors.initials: G
authors.lastname: South
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001993:Bronchodilator Agents / Q000627:therapeutic use; D015897:Comorbidity; D035061:Control Groups; D004739:England / Q000453:epidemiology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D015994:Incidence; D007252:Influenza Vaccines / Q000009:adverse effects* / Q000627:therapeutic use; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000145:classification / Q000150:complications* / Q000453:epidemiology; D012042:Registries; D012189:Retrospective Studies; D012720:Severity of Illness Index; D017678:Sex Distribution; D013147:Spirometry; D016896:Treatment Outcome
chemical_list: D001993:Bronchodilator Agents; D007252:Influenza Vaccines