RESUMEN
<p><b>OBJECTIVE</b>To describe epidemiological characteristics of an outbreak of severe acute respiratory syndrome (SRAS) in Dongcheng District, Beijing during March to June 2003.</p><p><b>METHODS</b>Data of SARS cases notified from Dongcheng District Center for Disease Control and Prevention (CDC) and supplemented by other channels were collected. All data were input into dataset files by Microsoft Excel-2000 software and analyzed with SPSS version 10.0 software.</p><p><b>RESULTS</b>Totally, 572 cases notified were collected during this period in Dongcheng District, Beijing, and 99 of them were excluded from SARS, because of diagnosis of common cold, pneumonia, measles, or rubella, etc. Actually, 473 SARS cases were analyzed. Attack rate of SARS in permanent residents of Dongcheng was 28.3 per 100,000. Forty-one of them died, with a case-fatality ratio of 8.7%. Outbreak of SARS in Dongcheng District started on March 14, with a peak during mid- and late April, and dropped from May 5, 2003. Persons were all susceptible to SARS, with the highest proportion at ages of 20-50 years, which accounted for 68.7% of the total cases. Average age of the patients at their onset was 40.7 years. No gender difference in SARS cases was found. Number of SARS cases in health care workers (HCWs) accounted for 18.0% and that in the retired persons accounted for 15.4% of the total cases. Cases occurred in all 10 sub-districts of Dongcheng. Totally, 230 of the 572 notified cases (40.2%) hospitalized at local hospitals under the jurisdiction of Dongcheng District. Eighteen of 85 cases of SARS occurred in health care workers of local hospitals, accounting for 4.5% of the total number of health care workers working at the wards caring for SARS patients or at fever clinics. There were 34.7% of SARS cases without any contact histories before their onset. Familial aggregation phenomena were observed in 41.8% of the cases and 18.1% of households. And, 7.4% (attack rate) in those exposed to SARS cases suffered the illness during the periods of quarantine.</p><p><b>CONCLUSIONS</b>SARS appeared outbreak in Dongcheng District, Beijing during March to June 2003. People were all susceptible to SARS, which mainly threatened the young adults and the middle-aged, as well as health care workers and the retired workers. Main mode of transmission was exposure to SARS patients in a near distance at hospitals or families. Prevention and control of SARS should be focused on early isolation of patients and quarantine for the contacts. Current available measures to prevent and control SARS proved effective.</p>