title: Pandemic influenza A(H1N1)pdm09: risk of infection in primary healthcare workers.
abstract: BACKGROUND
  Healthcare workers in primary care are at risk of infection during an influenza pandemic. The 2009 influenza pandemic provided an opportunity to assess this risk.
  
  
  OBJECTIVE
  To measure the prevalence of seropositivity to influenza A(H1N1)pdm09 among primary healthcare workers in Canterbury, New Zealand, following the 2009 influenza pandemic, and to examine associations between seropositivity and participants' sociodemographic characteristics, professional roles, work patterns, and seasonal influenza vaccination status.
  
  
  METHODS
  An observational study involving a questionnaire and testing for influenza A(H1N1)pdm09 seropositivity in all primary healthcare workers in Canterbury, New Zealand between December 2009 and February 2010. Method Participants completed a questionnaire that recorded sociodemographic and professional data, symptoms of influenza-like illness, history of seasonal influenza vaccination, and work patterns. Serum samples were collected and haemagglutination inhibition antibody titres to influenza A(H1N1)pdm09 measured.
  
  
  RESULTS
  Questionnaires and serum samples were received from 1027 participants, from a workforce of 1476 (response rate 70%). Seropositivity was detected in 224 participants (22%). Receipt of seasonal influenza vaccine (odds ratio [OR] = 2.0, 95% confidence interval [CI] = 1.2 to 3.3), recall of influenza (OR = 1.9, 95% CI = 1.3 to 2.8), and age ≤45 years (OR = 1.4, 95% CI = 1.0 to 1.9) were associated with seropositivity.
  
  
  CONCLUSIONS
  A total of 22% of primary care healthcare workers were seropositive. Younger participants, those who recalled having influenza, and those who had been vaccinated against seasonal influenza were more likely to be seropositive. Working in a dedicated influenza centre was not associated with an increased risk of seropositivity.
authors.affiliation: Department of Public Health and General Practice, University of Otago, Christchurch, New Zealand. ben.hudson@otago.ac.nz
authors.forename: Ben
authors.initials: B
authors.lastname: Hudson
authors.forename: Les
authors.initials: L
authors.lastname: Toop
authors.forename: Dee
authors.initials: D
authors.lastname: Mangin
authors.forename: Cheryl
authors.initials: C
authors.lastname: Brunton
authors.forename: Lance
authors.initials: L
authors.lastname: Jennings
authors.forename: Lynn
authors.initials: L
authors.lastname: Fletcher
mesh_terms: D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood; D005260:Female; D006282:Health Personnel; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D017758:Infectious Disease Transmission, Patient-to-Professional; D053118:Influenza A Virus, H1N1 Subtype / Q000472:pathogenicity*; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000097:blood / Q000635:transmission*; D008297:Male; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D058873:Pandemics; D015995:Prevalence; D011320:Primary Health Care; D016036:Seroepidemiologic Studies; D011795:Surveys and Questionnaires; D013997:Time Factors
chemical_list: D000914:Antibodies, Viral; D007252:Influenza Vaccines