And in Singapore, they predict the country could move away from its containment strategy to the mitigation phase - that is, caring for those who are ill - as early as in a week or two.

In a span of just under three weeks, Singapore has detected some 50 confirmed H1N1 flu cases. And the numbers are expected to surge with the rapid movement of the virus brought about by travel patterns during Singapore's traditional mid-year school holidays.

Health experts said Singapore's current strategy of containment - that is, quarantining H1N1 cases - may no longer be sustainable.

The Health Ministry has said it will move to the mitigation stage only when there is sustained community spread. So far there has only been one local H1N1 transmission in the country.

Dr Chong Yeh Woei, president, Singapore Medical Association, said: "We will be going into the mitigation phase sooner rather than later. I say this because I think that the resources of contact tracing, and quarantining people and isolating people - all these resources, I believe are being stretched to the limit right now.

"We have 74 countries that have the H1N1 virus, we have 10 countries that are put on the hot list. I think it is a matter of time before our resources are overwhelmed and we will have to go to the mitigation phase. Coupled by the fact the we have the school holidays, and the children coming back from holidays will be coming back to school."

The infection rate for H1N1 is relatively high - for every confirmed case, the virus may infect another 2.2 or 3 patients.

Mortality rate is about double that of seasonal flu. So death occurs in about two in every 1,000 patients.

So as a precautionary measure, doctors said it may be practical to keep schools closed for at least another week.

Dr Lee Yik Voon, family physician, said: "This may be based on what is experienced by other countries when the students come back from school holidays...you have a very high infection rate, like Japan, like Australia.

"For flu to spread, it requires close proximity. School is a place where kids get together. If you can prevent that for two weeks, I think you can break the chain of infection."

And since Home Quarantine Orders will no longer be enforced once mitigation sets in, experts said the onus is on the individual to act responsibly - meaning voluntary home quarantine if you are infected.

Dr Chong said: "The onus will be on the individual. He will have to make sure that if he is unwell, he will be getting early treatment, he will be looking after his loved ones and family members. He will make sure that he isolates himself, he will not infect his family members and he waits till he is completely well before he goes back to work."

Dr Philippe Barrault, group medical director, Asia, International SOS, said: "We need to remember this is very much an unknown virus with the ability to mutate very rapidly, to catch the patterns of virus it may meet in the process of going from, for example, one hemisphere to the other one.

"So far the severity is not one of the main issues, but it may become a big problem."

Doctors said they would be looking out for certain groups of vulnerable patients, including pregnant women, those between the ages of 30 and 50, and those with respiratory and cardio diseases. Also at risk are immuno-compromised patients such as those undergoing chemotherapy.

Dr Lee said: "You no longer have the fear of being ferried or pushed to Tan Tock Seng Hospital anymore. What happens is that you will probably be tested in that clinic. We will probably do a swab to test to see whether you are Influenza positive, and if you are, and you belong to a high risk group, we start treating you with Tamiflu."

Doctors here said that as soon as the alert button is pushed and Singapore moves to the mitigation stage, the Health Ministry will issue a stockpile of Tamiflu to all 900 or so Pandemic Preparedness Clinics. Already, the clinics have been issued Personal Protection Gears by the the Ministry, in an exercise conducted about two weeks ago.

Some virologists are warning of a potentially more lethal and stronger spread of the virus when the Northern hemisphere experiences winter at the end of the year.

They are watching to see how the virus mutates and reacts. But doctors said the hope could really lie in the development of a vaccine to counter-act against the effects of the H1N1 flu. - CNA/ms

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