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Severe Acute Respiratory Syndrome --- Taiwan, 2003
On April 22, 2003, the Taiwan Department of Health (DOH) was notified of seven cases of severe acute respiratory syndrome (SARS) among health-care workers (HCWs) at a large municipal hospital in Taipei (hospital A). Subsequent cases at eight hospitals have been associated with exposures at hospital A. Previously, all reported cases had been associated with persons recently returning to Taiwan from SARS-affected regions. This report summarizes epidemiologic findings of the outbreak in Taiwan and describes the impact of health-care--associated transmission of SARS.
As of May 22, a total of 483 probable cases had been reported (Figure 1). All probable SARS patients were hospitalized; 84 (17%) had been discharged, and 60 (12%) had died (Table). The median age of probable SARS patients was 43 years (range: 9 months--91 years); 341 (71%) cases were from Taipei City and Taipei County, the largest metropolitan region of the island. The first patient reported had onset of illness on February 25; the majority of cases occurred after April 21 and were associated with transmission in health-care settings.
Initial Cases (March 14--April 21)
Taiwan (2002 population: 23 million) has extensive business ties with Hong Kong and mainland China where SARS cases have been reported. The first case in Taiwan was identified on March 14 in a traveler from Guangdong Province in China. During March 14--April 21, Taiwan reported 28 probable SARS cases; of these, four resulted from secondary transmission (one HCW and three family contacts). During this period, SARS was characterized by sporadic cases among business travelers who were cared for primarily at large academic hospitals; secondary spread was limited to identified contacts. Initial actions by DOH included the formation of a SARS advisory committee, infection-control training, contact tracing and quarantine, and airport and border surveillance. Because of Taiwan's success with SARS control, in early April, the World Health Organization changed Taiwan's designation from an "affected area" to an "area with limited local transmission."
Health-Care--Associated Transmission (April 22--May 22)
Since April 22, SARS cases in Taiwan have increased and have been associated primarily with health-care settings. During April 22--May 1, the number of probable cases in Taiwan more than tripled, from 28 to 89. The source of the outbreak was hospital A, where an unrecognized SARS index patient had multiple exposures with patients, visitors, and HCWs who were not protected adequately to prevent acquisition of SARS.
Hospital A. The index patient was a laundry worker aged 42 years with diabetes mellitus and peripheral vascular disease who was employed at hospital A. On April 12, the worker had onset of fever and diarrhea and was evaluated in the emergency department (ED) on April 12, 14, and 15. The patient remained on duty and interacted frequently with patients, staff, and visitors. The patient had sleeping quarters in the hospital's basement and spent off-duty time socializing in the ED. On April 16, because of worsening symptoms, the patient was admitted to ward 8B of the hospital with a diagnosis of infectious enteritis. Stool samples revealed the presence of leukocytes, but cultures were negative. The patient was treated with intravenous antibiotics and the fever resolved. On April 18, the patient became short of breath. A chest radiograph showed bilateral infiltrates, and the patient was transferred to an isolation room in the intensive care unit for possible SARS. During the next few days, the patient had progressive respiratory failure and was intubated on April 22. A polymerase chain reaction (PCR) test was positive for SARS-associated coronavirus (SARS-CoV); the patient died on April 29. The source of infection for the patient is unknown.
The initial cluster of SARS cases reported on April 22 from hospital A included patients, visitors, and HCWs. The symptomatic HCWs included two nurses, a doctor, an administrator, a radiology technician, a nursing student, and another laundry worker. On the basis of epidemiologic links among the cases, 61 HCWs were identified and quarantined. Within 24 hours, 10 additional cases were identified from hospital A; none were from this quarantined cohort. By April 23, cases had been identified from the ED and from six different floors of the hospital, including ward 8B where the index patient had been admitted. The work location and number of case reports suggested widespread transmission. Because the index patient had been symptomatic for 6 days before SARS was diagnosed, the number of potentially exposed persons was estimated at 10,000 patients and visitors and 930 staff.
On April 23, DOH convened an emergency task force to plan the response to SARS transmission in hospital A. On April 24, hospital A was contained, and all patients, visitors, and staff were quarantined within the building. Home quarantine also was mandated for discharged patients and visitors who had been at hospital A since April 9. Inside the hospital, all recognized SARS patients were cohorted on two floors. Personal protective equipment (PPE) and disinfection materials were distributed, and active surveillance was enforced for all HCWs. However, incident SARS cases in hospital A continued to increase. During April 29--May 8, a total of 81 SARS patients were transferred to 15 hospitals throughout Taipei; it is unknown whether any of these patients were associated with secondary cases in other hospitals. All of the remaining patients (approximately 200) whose illnesses were not consistent with SARS case definitions were discharged to home quarantine or transferred to other facilities. As of May 22, a total of 137 probable cases were associated with exposures at hospital A, including 45 (33%) cases among HCWs; 26 (19%) persons died.
Secondary Clusters. To date, HCW clusters at eight additional hospitals in Taiwan have been linked to the initial outbreak at hospital A. Preliminary data suggest that many of these clusters occurred when presymptomatic patients or patients with SARS symptoms attributed to other causes were discharged or transferred to other health-care facilities. SARS has now extended to multiple cities and regions of Taiwan, including several university and private hospitals (Figure 2). Four of these hospitals, including a 2,300-bed facility in southern Taiwan, have discontinued emergency and routine services. Sporadic community cases also have been reported in Taipei and southern Taiwan.
In response, DOH has reorganized its outbreak response structure, appointed a SARS task force commander, and created an emergency operations center. Efforts have focused on limiting nosocomial transmission by designating dedicated SARS hospitals throughout the island. Approximately 100 fever clinics also have been established to identify potential SARS patients and minimize risk for transmission in EDs. Patient care capacity will be expanded by the construction of 1,000 negative pressure isolation rooms; by the end of May, approximately 1,700 such rooms will be available. Campsites and military facilities have been identified to accommodate quarantined residents, and home quarantine will be enforced through web-based cameras. Screening for fever in all patients, HCWs, and visitors has been instituted at all health-care facilities. DOH also has developed an infection-control curriculum to train infection-control teams on educating and monitoring HCWs. Standard operating procedures for the management and containment of nosocomial SARS clusters are being finalized.
Reported by: ML Lee, MD, CJ Chen, ScD, IJ Su, MD, KT Chen, MD, CC Yeh, MD, CC King, PhD, HL Chang, MPH, YC Wu, MD, MS Ho, MD, DD Jiang, PhD, SARS Prevention Task Force, Dept of Health, Taiwan, Republic of China. World Health Organization, Geneva, Switzerland. SARS Investigative Team; D Wong, MD, EIS Officer, CDC.
Efforts to control SARS in Taiwan appeared to be effective for approximately 5 weeks after identification of the first travel-associated case (1). Despite national efforts to implement extensive control measures, unrecognized cases of SARS led to nosocomial clusters and subsequent spread to other health-care facilities and community settings. These clusters resulted in substantial morbidity and mortality and resulted in the closure of several large health-care facilities. In one neighborhood in Taipei, three hospitals were affected, impacting facility access and deterring residents from seeking routine medical care.
Although nosocomial transmission of SARS has been well-documented, Taiwan's experience demonstrates that spread among HCWs can occur despite knowledge about the epidemiology and transmission of SARS. Multiple factors probably contributed to the rapid and widespread transmission in hospital A. The index patient had been symptomatic with fever and diarrhea for 6 days before SARS was suspected, and infection-control procedures were implemented. SARS infection-control guidelines focused primarily on health-care workers. However, in Taiwan, visitors include personal attendants hired by families to provide care for inpatients. Personal attendants are not routinely supplied with PPE; some personal attendants had SARS and might have contributed to disease spread.
Unrecognized cases of SARS also have been implicated in recent outbreaks at health-care facilities in Singapore (2). Several factors might contribute to difficulties in recognizing cases of SARS. Early symptoms of SARS are nonspecific and are associated with other more common illnesses. Patients with SARS who are immunocompromised or who have chronic conditions (e.g., diabetes mellitus or chronic renal insufficiency) might not have fever when acutely ill or have symptoms attributable to underlying disease, delaying SARS diagnosis (2,3). PCR tests to detect SARS-CoV are readily available in Taiwan; however, these tests might not detect the virus early during illness, and a negative test result does not rule out SARS (4). Finally, some patients might not reveal useful contact information (e.g., exposure to an implicated health-care facility) for fear of being stigmatized by the local community or causing their friends and families to be quarantined.
In Taiwan, exposures within health-care facilities have accelerated SARS transmission. The public health investigation is ongoing, and the number of SARS cases associated with health-care settings will probably increase. The extensive outbreak in Taiwan underscores the need for HCW education that promotes the early recognition of SARS and the prompt implementation of appropriate infection-control procedures. These educational efforts should be directed to HCWs in all facilities, including smaller and nonacademic hospitals.
This report is based on data contributed by Taipei City Bur of Health; Field Epidemiology Training Program; Center for Disease Control Taiwan, Republic of China.
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