High incidence indicates the winter season could merge into summer without the usual dip in cases The number of people seeing doctors for the flu has reached a six-year high, sparking official warnings that the city faces a 'special' flu season this year. The rate had reached 89.5 flu-like illnesses per 1,000 consultations at general practitioners' clinics at the end of last month, the highest level of the year. Thomas Tsang Ho-fai, a consultant at the Department of Health's Centre for Health Protection, said levels appeared to be staying high. The highest previous peak was reported in the week ending January 30, 1999, with 123 cases per 1,000 consultations. While the city normally has two flu peak seasons, this year's pattern seems to be a continuous flow. 'There are no signs that the rates are going down even by the end of May,' Dr Tsang said. 'It is quite special.' He expected the rates would remain high through the first two weeks of June, indicating the summer flu season would arrive earlier than the usual July to August. Dr Tsang said he was worried that with three flu strains circulating, the chance of their mixing was higher, raising the possibility of a stronger mutated strain. Most patients were elderly, particularly those who live in homes for the aged. Many had required hospital treatment, he said. Mass flu vaccination of the elderly might have helped but would not significantly reduce the number of people falling sick. The vaccine reduces the chance of people suffering from flu complications and lowers the number of people admitted to hospital. Dr Tsang said the vaccine containing the California (H3N2) flu strain, which is different from the previously circulating Fujian flu, would not be available in the city until August or September. The two other components in the vaccine would be the New Caledonia H1N1 flu, circulating since 1999, and the Shanghai flu B strain. On the first anniversary of the establishment of the Centre for Health Protection, its controller, Leung Pak-yin, said contingency plans for a flu pandemic, which is expected to make 15 per cent of the city population sick, have been put in place in many areas. A 24-hour website will be set up, he said. In the event of a pandemic, he said private doctors should continue their service so patients would not be concentrated in one place and to provide more choice. A flu pandemic would be different from the 2003 Sars outbreak, in that the aim of a flu preparedness plan was to decrease the mortality and morbidity and that flu could not be totally avoided, he said. With Sars, the strategy had been to prevent infection. The government's plan includes a three-level response system - alert, serious and emergency - based on different risk-graded scenarios. The plans came amid signs that the H5N1 bird flu is acquiring the ability to infect people more easily. Since January last year, there have been 97 human cases and 53 deaths reported in Vietnam, Thailand and Cambodia.