SARS: hospital infection control and admission strategies

Abstract

Nosocomial clustering with transmission to health care workers, patients and visitors is a prominent feature of severe acute respiratory syndrome (SARS). Hospital outbreaks of SARS typically occurred within the first week after admission of the very first SARS cases when the disease was not recognized and before isolation measures were implemented. In the majority of nosocomial infections, there was a history of close contact with a SARS patient, and transmission occurred via large droplets, direct contact with infectious material or by contact with fomites contaminated by infectious material. In a few instances, potential airborne transmission was reported in association with endotracheal intubation, nebulised medications and non-invasive positive pressure ventilation of SARS patients. In all SARS-affected countries, nosocomial transmission of the disease was effectively halted by enforcement of routine standard, contact and droplet precautions in all clinical areas and additional airborne precautions in the high-risk areas. In Hong Kong, where there are few private rooms for patient isolation, some hospitals have obtained good outcome by having designated SARS teams and separate wards for patient triage, confirmed SARS cases and step-down of patients in whom SARS had been ruled out. In conclusion, SARS represents one of the new challenges for those who are involved in hospital infection control. As SARS might re-emerge, all hospitals should take advantage of the current SARS-free interval to review their infection control programmes, alert mechanisms, response capability and to repair any identified inadequacies.

Figure 1

Diagram showing patient flow at the Queen Mary Hospital during the outbreak period of SARS in Hong Kong, March—May 2003. ¹Total number of patients admitted to triage, step‐down or SARS wards. Number in brackets refers to number of patients subsequently identified as probable SARS. ²Once a patient was identified as a suspected SARS case, movement of all patients in the same cubicle were frozen (no new admission, no transfers‐in and no transfers‐out). This group of patients was be actively monitored for illness (fever and respiratory symptoms ± CXR), pending SARS clarification in the index patient. If probable SARS was confirmed in the index, active surveillance continued for 10 days.³Patients were kept for a minimum of 3 days in the step‐down ward before discharge. To prevent inadvertently sending an elderly person with incubating SARS back to an institute, residents of old age homes were kept in the step‐down ward or (after 3 days) in a cohorted area for 10 days before discharge. All patients discharged before the 10‐day minimum period of surveillance were monitored daily (by phone calls) for illness (fever and respiratory symptoms).