Chan, Hong Kong's former director of health, was speaking at the annual meeting of the WHO's Western Pacific region. She said rising swine flu infections in Hong Kong, Japan, Canada and Britain showed a winter peak in infections was coming.

At least 190 countries have reported swine flu infections, and the disease is killing more people aged 30 to 50, including pregnant women, than flu commonly does. Hong Kong yesterday reported its 16th death from swine flu - a 37-year-old man with no underlying condition that would have made him more vulnerable to infection.

The city reported 446 new cases of swine flu yesterday, taking the total to 22,500. Hong Kong's secretary for food and health, Dr York Chow Yat-ngok, said it was important the city continue tracking the virus.

He said Hong Kong would consider winding down some of its measures against swine flu 'in due course', and admitted that the function of health declarations at the borders was diminishing. But he said the measure helped alert travellers to the risks of swine flu.

Chan said evidence was growing that antiviral drugs could reduce the risk of severe cases, and results of early clinical trials suggested that a single dose of vaccine would be sufficient to confer protection in healthy adults.

'If confirmed, this finding will literally double the amount of vaccine available,' she told the conference.

Representatives of 37 states and territories are attending the conference. Fair access to vaccines is now high on the WHO's agenda. It aims to secure 300 million doses of swine flu vaccine for poor countries by persuading drug makers to donate 150 million and soliciting donations to buy a further 150 million. That would be enough to protect 15 per cent of people in the 85 poorest countries.

The new virus had not mutated, the conference heard, and its resistance to drug treatment was low, with only about 25 patients worldwide having failed to respond to treatment with Tamiflu - the main antiviral used on people suffering from the A(H1N1) flu.

WHO regional director Dr Shin Young-soo said the Western Pacific, having been ground zero in the battle against Sars and bird flu, was well prepared to deal with swine flu. China had become the first country to start inoculating its people after the government approved vaccines produced by five domestic firms.

Chow said Beijing had promised to help the city out if it could not get vaccine supplies elsewhere. 'The mainland has a shortage of vaccine, so it is unlikely Hong Kong will buy vaccine from it. But the central government has assured us that if Hong Kong cannot get the supplies from other sources, we can get help.'

The man who died of swine flu in Hong Kong yesterday came down with flu symptoms on September 1 and was admitted to the isolation ward at Alice Ho Miu Ling Nethersole Hospital on September 5, when he was confirmed to have the disease. He was prescribed Tamiflu and antibiotics but his condition deteriorated. He was transferred to the intensive care unit and put on a ventilator.

The burden of swine flu on the city's public health care system has not yet worsened despite a rise in cases. Yesterday, hospitals were treating 196 cases, eight of them serious and seven critical. The daily average is around 150 patients, including 10 with severe complications.

Eleven schools will suspend classes for a week from today because of swine flu outbreaks. Of 824 pupils who have fallen ill at the schools, seven were admitted to hospital and another 23 confirmed to have been infected. Meanwhile, residents and staff at a Sheung Shui elderly people's home were put under medical watch after a 86-year-old resident contracted swine flu. He is in stable condition.

Chow said some doctors thought it might not be a bad thing for Hong Kong to experience mild cases of swine flu. 'It means as we approach the winter peak, quite a number of people will already have immunity.'