The WHO has praised Hong Kong's health and hygiene measures, and local officials remain committed to maintaining the city's Sars-free status.

Health measures at border crossings and Hong Kong International Airport (HKIA) have been stringent since the last outbreak of the virus. Temperature screening and health declaration forms are routine procedures for every passenger travelling into and out of Hong Kong. The Government allocated HK$400 million (US$51 million) to provide some 1,300 isolation beds for Sars patients in nine hospitals that are being upgraded for this purpose. Active surveillance is carried out in clinics, schools, hospitals and throughout the community.

"We have done all we can to better prepare ourselves for a re-emergence of Sars," said Dr Yeoh. "We have sufficient facilities and manpower to deal with any new cases."

WHO regional director for the Western Pacific region, Dr Shigeri Omi, said that the case was confirmed as the Sars virus but "There were no pneumonia findings in the chest X-ray. This is not being viewed as a return of the disease, although continued vigilance is recommended."

The WHO is working with China's Ministry of Health on an enhanced Sars surveillance initiative.

"In the coming months, there will likely be false alarms for Sars. But rather than creating anxiety, these alerts should serve as evidence that the disease surveillance system is working, since the disease's symptoms closely resemble those of many other respiratory illnesses," said WHO's China Representative Dr Henk Bekedam.

Reuters reported that Swiss company Berna Biotech has developed a prototype vaccine against the Sars virus and would develop the product if the disease showed signs of re-emerging.