Surveillance of severe acute respiratory syndrome (SARS) in the post-outbreak period.

INTRODUCTION: This retrospective one-month survey evaluated the practicality of post-severe acute respiratory syndrome (SARS) surveillance recommendations in previously SARS-affected countries, namely Singapore. These included staff medical sick leave for febrile illness, inpatient fevers, inpatient pneumonia, atypical pneumonia, febrile illnesses with significant travel history and sudden unexplained deaths from pneumonia/ adult respiratory distress syndrome (ARDS). METHODS: Surveillance data on medical sick leave of staff, all inpatient fevers, all febrile (temperature greater than or equal to 38 degrees Celsius) inpatient pneumonia, including atypical pneumonia, and deaths from pneumonia were collected from sick leave reports, ward reports, isolation room rounds and mortuary reports from 1 to 28 September 2003. RESULTS: Baseline results show 167 (1.4/1000 staff-days) observed in staff sick leave for febrile illnesses, and 1798 (71.3/1000 bed-days) observed for inpatient fever. There were 40, 31 and 12 instances, respectively, of staff having temperatures of high fever (greater than or equal to 38 degrees Celsius), prolonged sick leave (3 days or more), and repeated sick leave (within 7 days) for febrile illnesses. An average of 4.6 wards a day potentially fulfilled the World Health Organisation SARS alert criteria. Of 27 cases with fever, pneumonia and a total white count of less than 10,000 cells per cubic mm as per Ministry of Health, Singapore criteria for the diagnosis of atypical pneumonia, only five were identified by clinicians. CONCLUSION: Surveillance is time-consuming and current recommendations are not specific enough to be used practically. Surveillance indicators for inpatients must overcome a high degree of background noise.