Epidemiology and Infection



Environmental factors on the SARS epidemic: air temperature, passage of time and multiplicative effect of hospital infection


KUN LIN a1c1, DANIEL YEE-TAK FONG a2a3, BILIU ZHU a1 and JOHAN KARLBERG a3
a1 Department of Public Health, Shantou University Medical College, Shantou, PR China
a2 Department of Nursing Studies, Faculty of Medicine, the University of Hong Kong, Hong Kong SAR, PR China
a3 Clinical Trials Centre, Faculty of Medicine, the University of Hong Kong, Hong Kong SAR, PR China

Article author query
lin k   [PubMed][Google Scholar] 
yee-tak fong d   [PubMed][Google Scholar] 
zhu b   [PubMed][Google Scholar] 
karlberg j   [PubMed][Google Scholar] 

Abstract

The study sought to identify factors involved in the emergence, prevention and elimination of severe acute respiratory syndrome (SARS) in Hong Kong during 11 March to 22 May 2003. A structured multiphase regression analysis was used to estimate the potential effects of weather, time and interaction effect of hospital infection. In days with a lower air temperature during the epidemic, the risk of increased daily incidence of SARS was 18·18-fold (95% confidence interval 5·6–58·8) higher than in days with a higher temperature. The total daily new cases might naturally decrease by an average of 2·8 patients for every 10 days during the epidemic. The multiplicative effect of infected hospital staff with patients in an intensive care unit (ICU) and the proportion of SARS patients in ICUs might respectively increase the risk of a larger SARS epidemic in the community. The provision of protective gear in hospitals was also a very important factor for the prevention of SARS infection. SARS transmission appeared to be dependent on seasonal temperature changes and the multiplicative effect of hospital infection. SARS also appeared to retreat naturally over time.

(Published Online September 7 2005)
(Accepted June 15 2005)
(September 7 2005)


Correspondence:
c1 Department of Public Health, Shantou University Medical College, 22, Xin Ling Road, Shantou 515031, Guangdong, People's Republic of China. (Email: klin@stu.edu.cn)


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