Objective To investigate the epidemiologic features of an outbreak of SARS that occurred in a single diabetes room of a general hospital in Beijing in late March 2003.
Methods Field investigation was carried out in the ward, the nursing log and the hospitalization medical record of correlative patients were consulted. SARS-CoV in serum specimen from SARS patient was detected by PCR.
Results The room where SARS outbreak occurred was on the 13th floor of the 16-story main ward building. There were 6 beds in the room, living with 6 female patients (aged 45-67) who were all hospitalized due to type 2 diabetes. On March 24, 2003, Patient 1 began to have a fever and cough, chest X-ray showed pneumonia. Five and six days later, Patient 2 and Patient 3 began to have a fever, respectively. Finally, all of these 3 patients died. Their beds were all at the same side of the room, and the other 3 patients at the opposite side were not infected. Serum SARS CoV-RNA of the Patient 3 was positive by nest-PCR. The daughter-in-law of Patient 1 who accompanied Patient 1 by the bedside several days, mainly near the window, upwind of Patient 1, was not infected. Medical staff, family members and visitors of the 6 patients were not infected.
Conclusions This outbreak was not transmitted by aerosol. The distance droplets travels could be up to 3.43 meters. Droplet spread has direction, and the droplets direction of propagation is closely related with the wind direction and speed. Those at the downwind position of SARS patients were susceptible to be infected. Medical staff wore face masks and good natural ventilation of this ward building may be important reasons for the prevention of infection.
1 WHO. Case Definitions for Surveillance of Severe Acute Respiratory Syndrome (SARS). www.who.int/csr/sars/casedefinition/
2 Siegel JD, Rhinehart E, Jackson M, Chiarello L and the Healthcare Infection Control Practices Advisory Committee, 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings. http://www.cdc.gov/ncidod/dhqp/pdf/isolation2007.pdf.
3 Feigin RD, Baker CJ, Herwaldt LA, Lampe RM, Mason EO, Whitney SE. Epidemic meningococcal disease in an elementaryschool classroom. N Engl J Med 1982; 307(20):1255-1257.
4 Dick EC, Jennings LC, Mink KA, Wartgow CD, Inhorn SL. Aerosol transmission of rhinovirus colds. J Infect Dis 1987;156(3):442-448.
5 Xie X, Li Y, Chwang AT, Ho PL, Seto WH. How far droplets can move in indoor environments--revisiting the Wells evaporationfalling curve. Indoor Air 2007;17(3):211-225.
6 Dwosh HA, Hong HH, Austgarden D, Herman S, Schabas R. Identification and containment of an outbreak of SARS in a community hospital. CMAJ 2003;168(11):1415-1420.
7 Varia M, Wilson S, Sarwal S, McGeer A, Gournis E, Galanis E, et al. Investigation of a nosocomial outbreak of severe acute respiratory syndrome (SARS) in Toronto, Canada. CMAJ 2003;169:285-292.
8 Seto WH, Tsang D, Yung RW, Ching TY, Ng TK, Ho M, et al. Effectiveness of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome (SARS). Lancet 2003; 361(9368):1519-1520.
9 Lee N, Hui D, Wu A, Chan P, Cameron P, Joynt GM, et al. A major outbreak of severe acute respiratory syndrome in Hong Kong. N Engl J Med 2003; 348(20):1986-1994.
10 Chow KY, Lee CE, Ling ML, Heng DM, Yap SG. Outbreak of severe acute respiratory syndrome in a tertiary hospital in Singapore, linked to an index patient with atypical presentation: epidemiological study. BMJ 2004; 328(7433): 195.
12 Le DH, Bloom SA, Nguyen QH, Maloney SA, Le QM, Leitmeyer KC, et al. Lack of SARS transmission among public hospital workers, Vietnam. Emerg Infect Dis 2004; 10:265-268.
13 Jiang S, Huang L, Chen X, Wang J, Wu W, Yin S, et al. Ventilation of wards and nosocomial outbreak of severe acute respiratory syndrome among healthcare workers. Chin Med J (Engl) 2003;116(9):1293-1297.
14 Wei MT, de Vlas SJ, Yang Z, Borsboom GJ, Wang L, Li H, et al. The SARS outbreak in a general hospital in Tianjin, China: clinical aspects and risk factors for disease outcome. Trop Med Int Health 2009;14 Suppl 1:60-70.