An influenza strain that killed a six-year-old girl on Christmas Eve 2000 became the most common type of flu in Hong Kong last year. In the first 11 months of the year, 1,191 people contracted the New Caledonia strain of H1N1, according to the latest Department of Health figures. In contrast, 136 people contracted the Sydney flu H3N2 strain during the same period. The New Caledonia strain, which is related to Beijing flu, was first detected in the South Pacific in 1999. It has affected mainly youngsters since appearing in Hong Kong in 2000. The six-year-old girl died from acute encephalitis two days after being admitted to hospital. It was the first SAR death associated with New Caledonia. Legislator Dr Lo Wing-lok, an infectious disease specialist and president of the Hong Kong Medical Association, said youngsters were more susceptible to the New Caledonia strain because older people had, through exposure to other H1N1 strains, developed partial immunity to it. Most flu epidemics have been caused by H1N1 strains, the Department of Health said. Officials urged people to take precautions against influenza as the territory entered its peak flu season this month. Last year more than 45,000 people were given free anti-flu injections during the department's vaccination campaign.