title: Risk factors and effectiveness of preventive measures against influenza in the community.
abstract: BACKGROUND
  The role of different risk exposures and preventive measures against influenza has not been well established.
  
  
  OBJECTIVE
  The aim of this study was to evaluate risk factors and measures to prevent influenza infection in the community.
  
  
  METHODS
  We conducted a multicenter case-control study. Cases were 481 outpatients aged 18 years or older with laboratory-confirmed influenza A(H1N1)09 in the 2009-2010 season in Spain. A control was selected for each case from outpatients from the same area matched by age and date of consultation. Information on risk situations, preventive measures and other variables was obtained by interview and review of the medical record.
  
  
  RESULTS
  In the multivariate conditional logistic regression analysis, the risk of a diagnosis of influenza increased with the number of cohabitants (compared with <3 cohabitants, three cohabitants had an OR= 1·80, 95% CI 1·12-2·89, and ≥5 cohabitants had an OR = 2·66, 95% CI 1·31-5·41) and for health care workers (OR = 2·94, 95% CI 1·53-5·66). The use of metropolitan public transport was associated with a lower frequency of a diagnosis of influenza (OR = 0·45, 95% CI 0·30-0·68) but not the use of taxis or long-distance transport. The influenza A(H1N1)09 vaccine had a protective effect (OR =0·13, 95% CI 0·04-0·48), unlike hand washing after touching contaminated surfaces or the use of alcohol-based hand sanitizers.
  
  
  CONCLUSIONS
  The home environment appears to play an important role in the spread of influenza in adults, but not the use of public transport. Health care workers have a higher risk of contracting influenza. Vaccination was the most effective preventive measure.
authors.affiliation: Instituto de Salud Pública de Navarra, 31003 Pamplona, Spain. jcastilc@navarra.es
authors.forename: Jesús
authors.initials: J
authors.lastname: Castilla
authors.forename: Pere
authors.initials: P
authors.lastname: Godoy
authors.forename: Ángela
authors.initials: Á
authors.lastname: Domínguez
authors.forename: Vicente
authors.initials: V
authors.lastname: Martín
authors.forename: Miguel
authors.initials: M
authors.lastname: Delgado-Rodríguez
authors.forename: Iván
authors.initials: I
authors.lastname: Martínez-Baz
authors.forename: Maretva
authors.initials: M
authors.lastname: Baricot
authors.forename: Nuria
authors.initials: N
authors.lastname: Soldevila
authors.forename: José M
authors.initials: JM
authors.lastname: Mayoral
authors.forename: Jenaro
authors.initials: J
authors.lastname: Astray
authors.forename: José M
authors.initials: JM
authors.lastname: Quintana
authors.forename: Rafael
authors.initials: R
authors.lastname: Cantón
authors.forename: Ady
authors.initials: A
authors.lastname: Castro
authors.forename: Fernando
authors.initials: F
authors.lastname: González-Candelas
authors.forename: Jordi
authors.initials: J
authors.lastname: Alonso
authors.forename: Marc
authors.initials: M
authors.lastname: Saez
authors.forename: Sonia
authors.initials: S
authors.lastname: Tamames
authors.forename: Tomás
authors.initials: T
authors.lastname: Pumarola
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000517:prevention & control*; D005191:Family Characteristics; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control*; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D011247:Pregnancy; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology; D014186:Transportation; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines