SARS in Healthcare Facilities, Toronto and Taiwan (original) (raw)

2004, Emerging Infectious Diseases

High Risk for Transmission in Healthcare Workers, Patients, and Visitors At the onset of the global outbreak, patients infected with SARS coronavirus (SARS-CoV) sought care at emergency departments for symptoms of what appeared to be common respiratory infections. During such encounters, minimal infection control measures were implemented since most known infections did not warrant them. However, in some circumstances, conditions were favorable for efficient transmission of SARS. Many exposed healthcare workers, patients, and visitors became infected and subsequently transmitted infection to others in their healthcare facilities. Nosocomial transmission was the primary accelerator of SARS infections, accounting for 72% of cases in Toronto (3) and 55% of probable cases in Taiwan (Table) (4). In Toronto, the outbreak unfolded in two phases, both attributable to nosocomial transmission (Figure 1). The first phase resulted from a case of unrecognized SARS in an infected contact of a recent traveler to Hong Kong (5). The second phase resulted from unknown transmission of SARS among hospitalized patients during a period when healthcare workers were being instructed to wear personal protective equipment, including gowns, gloves, and masks (6). In Taiwan, the outbreak had two phases (Figure 1). The first phase consisted of sporadic SARS cases in travelers without nosocomial transmission (7). In the second phase, transmission at one municipal hospital ignited a number of subsequent nosocomial outbreaks when SARS patients were transferred to other facilities (4). A number of factors may make nosocomial transmission a common mode of infection. Unlike many other viral respiratory diseases in which the concentration of virus is greatest on disease onset, the concentration of SARS-CoV in secretions appears to peak approximately 10 days after symptom onset (8) when a patient's symptoms are often worsening and may require medical attention. Thus, patients may be most capable of transmitting the virus at the point when they encounter healthcare workers. In addition, transmission appears to be primarily through exposure to respiratory droplets and direct contact with patients