title: Can influenza vaccination coverage among healthcare workers influence the risk of nosocomial influenza-like illness in hospitalized patients?
abstract: BACKGROUND
  Approximately 20% of healthcare workers are infected with influenza each year, causing nosocomial outbreaks and staff shortages. Despite influenza vaccination of healthcare workers representing the most effective preventive strategy, coverage remains low.
  
  
  OBJECTIVE
  To analyse the risk of nosocomial influenza-like illness (NILI) among patients admitted to an acute care hospital in relation to influenza vaccination coverage among healthcare workers.
  
  
  METHODS
  Data collected over seven consecutive influenza seasons (2005-2012) in an Italian acute care hospital were analysed retrospectively. Three different sources of data were used: hospital discharge records; influenza vaccination coverage among healthcare workers; and incidence of ILI in the general population. Clinical modification codes from the International Classification of Diseases, 9(th) Revision were used to define NILI.
  
  
  RESULTS
  Overall, 62,343 hospitalized patients were included in the study, 185 (0.03%) of whom were identified as NILI cases. Over the study period, influenza vaccination coverage among healthcare workers decreased from 13.2% to 3.1% (P < 0.001), whereas the frequency of NILI in hospitalized patients increased from 1.1‰ to 5.7‰ (P < 0.001). A significant inverse association was observed between influenza vaccination coverage among healthcare workers and rate of NILI among patients (adjusted odds ratio 0.97, 95% confidence interval 0.94-0.99).
  
  
  CONCLUSIONS
  Increasing influenza vaccination coverage among healthcare workers could reduce the risk of NILI in patients hospitalized in acute hospitals. This study offers a reliable and cost-saving methodology that could help hospital management to assess and make known the benefits of influenza vaccination among healthcare workers.
authors.affiliation: Department of Sciences for Health Promotion and Mother-Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy. Electronic address: emanuele.amodio@unipa.it.
authors.forename: E
authors.initials: E
authors.lastname: Amodio
authors.affiliation: Department of Sciences for Health Promotion and Mother-Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Restivo
authors.affiliation: Department of Sciences for Health Promotion and Mother-Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Firenze
authors.affiliation: Department of Sciences for Health Promotion and Mother-Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Mammina
authors.affiliation: Department of Sciences for Health Promotion and Mother-Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Tramuto
authors.affiliation: Department of Sciences for Health Promotion and Mother-Child Care 'G. D'Alessandro', University of Palermo, Palermo, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Vitale
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003428:Cross Infection / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D003430:Cross-Sectional Studies; D005260:Female; D006282:Health Personnel; D006801:Humans; D017053:Infection Control / Q000379:methods; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D014611:Vaccination / Q000706:statistics & numerical data*; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines
keywords: Healthcare workers; Infection control; Influenza vaccination; Nosocomial influenza