Friendly exchange: Secretary for Health, Welfare & Food Dr Yeoh Eng-kiong and Director of Health Dr Margaret Chan speak by videophone with WHO's Executive Director for Communicable Disease, Dr David Heymann, who is in Geneva.

Hong Kong has already met one of three conditions necessary for the World Health Organisation to lift its travel advisory, Secretary for Health, Welfare & Food Dr Yeoh Eng-kiong says.

Speaking after a videoconference with the WHO's Executive Director for Communicable Disease, Dr David Heymann in Geneva, Dr Yeoh said that Hong Kong had not exported a single severe acute respiratory syndrome case for several weeks.

But there are two other conditions that have a stronger bearing on the advisory decision.

Magic new case number: 5

"They are most interested in the number of new cases on a daily basis - that's the main figure that they're interested in," Dr Yeoh said, adding that number is five. While Hong Kong has seen the number of new cases fall into the single digits in the last three days - to nine today, and eight in the two days previous - we need to continue our rigorous preventive measures.

"Dr Heymann was pleased that our control measures are effective and our numbers are coming down slowly but surely," Dr Yeoh said. "They can see the cases are coming down, but they're afraid they could go down and then go up again. We want to see them remain on the low side, that will give them confidence that the situation is under control."

Active SARS cases should fall to 60

The WHO would also like to see the number of active SARS cases fall to 60; as of today, there are 495 SARS patients in public hospitals, including 73 in ICU, and 91 recovering in convalescence wards.

The third condition revolves around the mode of transmission in the community. Dr Yeoh said the WHO is concerned there could be many cases in the community, and they have to look at the cases of infection from healthcare workers to others and from others to healthcare workers.

There is a flaw in the WHO definition of SARS, Dr Yeoh said: Anyone with atypical pneumonia who visited a SARS-affected area could be considered a suspect. Since Hong Kong is itself a SARS-affected area, many atypical pneumonia cases that are not caused by coronavirus - the virus identified as causing SARS - may be getting wrongly classified, he said.

"We may have overestimated the number of confirmed SARS cases," he says. "In future, we will do further lab tests to see how many are related to the coronavirus."

Blood tests to aid in SARS confirmation

The Hospital Authority is collecting blood samples from all of the 1,646 confirmed cases and will be able to do RNA sampling to see if the coronavirus is present. In another test, it will also check for antibodies to the coronavirus. "The WHO is looking forward to the information we're going to provide," Dr Yeoh said.

The WHO wishes to see good control and be assured that the measures are able to control the spread of the disease in the community, he said.

"We ourselves are very concerned about the control measures. If we had further outbreaks, even if they lift the travel advisory , it will just come back to haunt us."

WHO thanks HK for helping Malaysian ship's crew

He added that the WHO has been very encouraging. It also expressed its appreciation for Hong Kong's efforts to help sick crew members aboard a Malaysian-registered ship who thought they might have SARS symptoms. 

Dr Yeoh said that another videoconference will be arranged next week. "The travel alerts are considered on a weekly basis," he said. "But if there is any need, it could even be done in between."

The two sides had also discussed Hong Kong's plan to set up a centre for disease control. Both agreed that in future, Hong Kong would need to train more people. "The WHO is willing to work together with us in relation to the CDC concept... The form and nature of the centre will be discussed at greater length in future."

Boundary crossing measures deemed effective

Hong Kong's relationship with the Mainland also came into the conversation. The WHO asked about detailed arrangements at the land-boundary crossings. "We did explain to them that those measures [such as using infrared scanners to take temperature checks] are effective, that we've referred many cases to hospital for examination, and that two patients were intercepted and found to have SARS," he added.

"The WHO asked for this information to share with other countries for their reference."