title: [Pandemic influenza A (H1N1) virus infection factors among healthcare workers - a case-control study].
abstract: OBJECTIVE
  To explore factors related to pandemic influenza A (H1N1) virus infection among healthcare workers.
  
  
  METHODS
  H1N1 influenza confirmed cases of health workers in hospital of Beijing from Aug 30th 2009 to Jan 31st 2010 were included. A 1:4 matched case-control study was conducted with 54 healthcare workers who were infected by influenza A(H1N1) virus and 216 matched controls who were not infected. Face-to-face interview with questionnaires was used to collect information of work and family aspects of the study participants. Conditional logistic regression was used to analyze the H1N1 infection factors.
  
  
  RESULTS
  The age was 29.6 ± 7.4 years old and male subjects accounted for 17.4% (47/270). There were 5.6% (3/54) and 34.4% (74/216) of the cases get the influenza A (H1N1) vaccine immunization separately in the case group and control group. Among 18.5% (10/54) and 40.1% (88/216) of the cases and controls used high protection level masks during the epidemic. Besides, 33 (61.1%)and 161 (74.5%) cases lengthening the time of mask wearing separately. There were 13 (24.1%) and 85 (39.4%) cases using disposable tissue to clean hands in the case group and control group, 24 (44.4%) and 46 (21.3%) cases feel they were much easier to get infected in respiratory disease than others based on experience in the case and control group. Univariate analysis showed that factors such as using disposable tissue to clean hands (OR = 0.15, 95%CI = 0.04 - 0.57), lengthening the time of mask wearing (OR = 0.43, 95%CI = 0.20 - 0.92), using high protection level masks (OR = 0.26, 95%CI = 0.11 - 0.58), getting influenza A (H1N1) vaccine immunization (OR = 0.04, 95%CI = 0.01 - 0.32), much easier to get infected in respiratory disease than others based on experience (OR = 2.85, 95%CI = 1.44 - 5.62), were all associated with influenza A (H1N1) infection. Results of multivariate logistic regression analysis showed that variables such as history of influenza A (H1N1) virus immunization (OR = 0.18, 95%CI = 0.06 - 0.51), using high protection level masks (OR = 0.05, 95%CI = 0.01 - 0.35), much easier to get infected in respiratory disease than others based on experience (OR = 3.69, 95%CI = 1.58 - 8.63) were all correlated to influenza A (H1N1) infection.
  
  
  CONCLUSIONS
  Factors such as history of influenza A (H1N1) vaccine immunization, using high protection level masks and improving respiratory health can protect healthcare workers from infection of influenza A (H1N1).
authors.affiliation: Beijing Center for Disease Prevention and Control, Beijing 100013, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Deng
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiao-Li
authors.initials: XL
authors.lastname: Wang
authors.forename: Wen-Ting
authors.initials: WT
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Duan
authors.forename: Peng
authors.initials: P
authors.lastname: Yang
authors.forename: Xing-Huo
authors.initials: XH
authors.lastname: Pang
authors.forename: Quan-Yi
authors.initials: QY
authors.lastname: Wang
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D005260:Female; D006282:Health Personnel / Q000706:statistics & numerical data*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000453:epidemiology* / Q000517:prevention & control / Q000821:virology*; D008297:Male; D016272:Occupational Health; D058873:Pandemics; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines