Letters to the Editor
SARS or Not SARS: Outbreak of Fever in a State Mental Institute in Singapore
Dear Editor:
In mid-March 2003, Singapore reported its first cases of severe acute respiratory syndrome (SARS). By mid-July, the disease had claimed 32 lives, 206 people had been diagnosed with SARS, and 722 suspect cases had been reported. The outbreak in Singapore was characterized by the rapidity of nosocomial transmission, concentration in health care settings, and the large number of health care workers (HCWs) infected in several general hospitals.
Woodbridge Hospital is the only state mental institution in Singapore. It has 1900 beds, more than one-half of which are taken up by long-stay residents. A surveillance system was implemented following the SARS outbreak; it included monitoring the body temperature of all patients and staff 3 times daily, restricting movement of patients and visitors, and keeping track of staff movement to high-risk areas. On 8 May, 3 cases of fever were reported in 1 long- stay psychogeriatric ward; by 13 May, 34 patients and 14 HCWs developed fever. After consulting with the Ministry of Health, hospital administrators decided that the prudent course was to assume a SARS outbreak until proven otherwise. A “no-movement” order was imposed; that is, there were no admissions or discharges during this period. Further, the entire hospital staff—more than 1300 individuals—voluntarily quarantined themselves in specific facilities.
After investigations, the final diagnoses showed considerable heterogeneity: viral fever (60.4%), respiratory tract infection (22.9%), urinary tract infection (6.3%), soft tissue infection (2.1%), and fever of undetermined origin (8.3%). For all patients, polymerase chain reaction serology was negative for SARS- associated corona virus (SAR-CoV). Six out of 9 individuals tested positive for influenza B virus antigen on enzyme-linked immunosorbent assay. The quarantine was subsequently lifted, and normal services were restored in the hospital.
The high index of suspicion and lowered threshold for defining fever, coupled with the rigorous monitoring measures, resulted in the identification of a large number of febrile cases that might have been routinely missed. Fever is a cardinal sign of SARS (1); however, in long-stay facilities, a wide range of illnesses can cause the initial SARS-like symptoms of fever, myalgia, and dry cough. In countries affected by SARS, an outbreak of fever in a long-stay facility can create a dilemma concerning the appropriate course of action. To err on the side of caution by assuming SARS entails expending more resources, disrupting normal services, and creating emotional stress for all concerned. Conversely, erroneously assuming that an outbreak is not SARS would have dire consequences.
Surveillance of nosocomial infections is the cornerstone of all infection-control programs; it provides facility-endemic infection rates that help with tracking the time and place of infection trends (2). Another effective strategy is vaccination against influenza. The vaccine is cheap, has few side effects (3), and is recommended for preventing influenza (4). In SARS-affected regions, vaccination against influenza would also lessen the “background noise” in the crucial initial stages of deciding on the etiology of an outbreak of fever in long-stay facilities.
References
1. Tomlinson B, Cockram C. SARS: experience at Prince of Wales Hospital, Hong Kong. Lancet 2003;361:1486–87.
2. Stevenson KB. Regional data set of infection rates for long-term care facilities: description of a valuable benchmarking tool. Am J Infect Control 1999;27:20–6.
3. Stott DJ, Kerr G, Carman WF. Nosocomial transmission of influenza. Occup Med 2002;52:249–53.
4. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report. Recommendations and Reports 1999;48:1–28.
Siow Ann Chong, MBBS, MMed Psychiatry
Mythily Subramaniam, MBBS, MD Biochemistry
Hong Choon Chua, MBBS, MMed Psychiatry
Chien Earn Lee, MBBS. MMed
Republic of Singapore
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