title: Incidence and risk factors for acute respiratory illnesses and influenza virus infections in Australian travellers to Asia.
abstract: BACKGROUND
  Respiratory infections including influenza are a common cause of acute short-term morbidity in travellers and yet the risk of these infections is poorly defined.
  
  
  OBJECTIVE
  To estimate the incidence density of and risk factors for acute respiratory infections (ARIs) and influenza in Australian travellers to Asia.
  
  
  METHODS
  Travel-clinic attendees were prospectively identified and completed questionnaires (demographic data, travel itinerary, health and vaccination history) and also provided pre and post-travel serological samples for Influenza A and B (complement fixation test). Returned travellers with an ARI provided nasopharyngeal specimens for RT-PCR identification of respiratory viruses.
  
  
  RESULTS
  In this cohort (n = 387) of predominantly (72%) short-term travellers, 58% were female, the median age was 37 years and 69% were tourists. ARIs occurred in 109 travellers (28%) translating to an incidence of 106.4 ARIs per 10,000 traveller days (95% confidence interval CI 88.6-126.7). The traveller type of missionary or aid worker was a risk factor for acquiring an ARI (p = 0.03) and ARIs occurred early (< 30 days) in the travel period (p = 0.001). Four travellers (1%) acquired influenza A during travel translating to an incidence density of 3.4 infections per 10,000 days of travel (95% CI 1.4-8.6). Influenza vaccination was reported in 49% of travellers with a 3.5-fold higher incidence of influenza in unvaccinated travellers compared to vaccinated travellers (p = 0.883).
  
  
  CONCLUSIONS
  This is one of the largest prospective studies estimating the incidence of respiratory infections in travellers. These findings have important implications for practitioners advising prospective travellers and for public health authorities.
authors: Victorian Infectious Diseases Service, Royal Melbourne Hospital, Melbourne, Australia.
authors: Irani
authors: I
authors: Ratnam
authors: Jim
authors: J
authors: Black
authors: Karin
authors: K
authors: Leder
authors: Beverley-Ann
authors: BA
authors: Biggs
authors: Ian
authors: I
authors: Gordon
authors: Elizabeth
authors: E
authors: Matchett
authors: Alex
authors: A
authors: Padiglione
authors: Ian
authors: I
authors: Woolley
authors: Theo
authors: T
authors: Karapanagiotidis
authors: Tony
authors: T
authors: Gherardin
authors: Clarisse
authors: C
authors: Demont
authors: Christine
authors: C
authors: Luxemburger
authors: Joseph
authors: J
authors: Torresi
mesh_terms: D000208:Acute Disease; D000328:Adult; D001208:Asia / Q000453:epidemiology; D001315:Australia / Q000208:ethnology; D005260:Female; D006801:Humans; D015994:Incidence; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology*; D053208:Kaplan-Meier Estimate; D008297:Male; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D014195:Travel