Epidemiology: University Hospital experience

In March 2003, there was an outbreak of atypical pneumonia in Hong Kong and our institution was at its epicentre. Epidemiological investigations revealed that the initial outbreak at our institution was related to a single index case admitted to one of our medical wards.

In the early phase of the outbreak, the index case infected

• 55 health care workers in the same ward;

• 16 medical students who clinically examined the index case;

• 54 patients who were either nursed in the same ward or had visited their relatives.

It is postulated that the use of nebulized salbutamol for muco-ciliary clearance may have potentiated its transmission.

Diagnosis of SARS

At the time of writing, the diagnosis of severe acute respiratory syndrome (SARS) is still based on clinical and epidemiological information as in our previously reported cohort. According to the WHO case definition, patients are classified as ‘suspect’ or ‘probable’ cases, as discussed in the earlier chapter (Chapter 1). Cases are excluded if an alternative diagnosis can fully explain their illness. However, clinicians are advised that patients should not have their case definition category downgraded while awaiting results of laboratory testing or on the bases of negative results.