Specific features of the contact history of probable cases of severe acute respiratory syndrome

To describe the specific features of the contact history of probable cases of severe acute respiratory syndrome (SARS) in Beijing.Data of SARS cases notified from the Beijing Municipal Center for Disease Control and Prevention (BCDC) and supplemented by other channels were collected. All the data were analyzed by descriptive epidemiology.(1) The number of probable cases with contact history was significantly higher than the excluded cases. (2) The proportion of probable cases with contact history descended with epidemic development, but this situation did not occur in health care workers (HCWs). (3) The fatality rate of probable cases with contact history was significantly higher than the cases without contact history (OR = 1.489). (4) The proportion of probable cases with contact history was 85.86% among health care workers, which was significantly higher than that of non-health care workers (85.86% v.s. 56.44%, OR=4.69).(1) The susceptible persons with contact history may not get infected, and the contact history is just a sufficient condition of infecting SARS; (2) There are 3 conceivable reasons for the descending trend of the proportion in probable cases with contact history; (3) The contact history is one of the risk factors of the death of SARS cases; (4) The risk of contacting with SARS among health care workers is approximately 5 times higher than that of non-HCWs.