title: A comparative epidemiologic analysis of SARS in Hong Kong, Beijing and Taiwan.
abstract: BACKGROUND
  The 2002-2003 Severe Acute Respiratory Syndrome (SARS) outbreak infected 8,422 individuals leading to 916 deaths around the world. However, there have been few epidemiological studies of SARS comparing epidemiologic features across regions. The aim of this study is to identify similarities and differences in SARS epidemiology in three populations with similar host and viral genotype.
  
  
  METHODS
  We present a comparative epidemiologic analysis of SARS, based on an integrated dataset with 3,336 SARS patients from Hong Kong, Beijing and Taiwan, epidemiological and clinical characteristics such as incubation, onset-to-admission, onset-to-discharge and onset-to-death periods, case fatality ratios (CFRs) and presenting symptoms are described and compared between regions. We further explored the influence of demographic and clinical variables on the apparently large differences in CFRs between the three regions.
  
  
  RESULTS
  All three regions showed similar incubation periods and progressive shortening of the onset-to-admission interval through the epidemic. Adjusted for sex, health care worker status and nosocomial setting, older age was associated with a higher fatality, with adjusted odds ratio (AOR): 2.10 (95% confidence interval: 1.45, 3.04) for those aged 51-60; AOR: 4.57 (95% confidence interval: 3.32, 7.30) for those aged above 60 compared to those aged 41-50 years. Presence of pre-existing comorbid conditions was also associated with greater mortality (AOR: 1.74; 95% confidence interval: 1.36, 2.21).
  
  
  CONCLUSIONS
  The large discrepancy in crude fatality ratios across the three regions can only be partly explained by epidemiological and clinical heterogeneities. Our findings underline the importance of a common data collection platform, especially in an emerging epidemic, in order to identify and explain consistencies and differences in the eventual clinical and public health outcomes of infectious disease outbreaks, which is becoming increasingly important in our highly interconnected world.
authors.affiliation: School of Public Health, The University of Hong Kong, Pokfulam Road, Hong Kong.
authors.forename: Eric H Y
authors.initials: EH
authors.lastname: Lau
authors.forename: C Agnes
authors.initials: CA
authors.lastname: Hsiung
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Cowling
authors.forename: Chang-Hsun
authors.initials: CH
authors.lastname: Chen
authors.forename: Lai-Ming
authors.initials: LM
authors.lastname: Ho
authors.forename: Thomas
authors.initials: T
authors.lastname: Tsang
authors.forename: Chiu-Wen
authors.initials: CW
authors.lastname: Chang
authors.forename: Christl A
authors.initials: CA
authors.lastname: Donnelly
authors.forename: Gabriel M
authors.initials: GM
authors.lastname: Leung
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002681:China / Q000453:epidemiology; D015897:Comorbidity; D004196:Disease Outbreaks; D005260:Female; D005843:Geography; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D045169:Severe Acute Respiratory Syndrome / Q000453:epidemiology* / Q000401:mortality*; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult