China is likely to face an earlier-than-usual flu season this winter, dominated by a strain different from last year's, health experts said as they urged the public, especially high-risk groups, to promptly get vaccinated.

The latest data from the Chinese Center for Disease Control and Prevention shows that flu activity is increasing in southern China, but levels in the north remain low.

While the typical peak season for influenza in much of China spans from late November through February, experts said this year's outbreak may arrive earlier — a trend that has already been observed in several Asian and European countries.

"Following a significant increase in cases in Japan, the nation's health authorities announced the start of this year's flu season on Oct 3, which is about five weeks earlier than the usual start in November or December," said Li Tongzeng, chief physician of the infectious disease department at Beijing You'an Hospital.

Similarly, South Korea's disease control agency issued a nationwide flu advisory on Oct 17, which was two months earlier than last year's, according to a report by The Chosun Daily.

Li added that a similar trend is emerging in Europe, with the United Kingdom, Italy and Germany recently reporting a marked increase in flu patients.

"Many experts predict that flu cases will rise earlier this year and reach higher numbers than in the previous season in China," he added.

Data from the China CDC also shows that for the week from Oct 6 to 12, more than 90 percent of flu samples tested nationwide were identified as the H3N2 strain of influenza A.

Li said that the H3N2 strain also dominated the past flu season in Australia and New Zealand in summer, as well as the recent surge in cases in Europe.

"Since last year's primary circulating strain was the H1N1 subtype of influenza A, the public may have lower immunity against H3N2 this year, making heightened precautions necessary," he said.

The H1N1, H3N2, and influenza B are the three main strains responsible for seasonal flu epidemics worldwide. They cause similar symptoms, including fever, cough, sore throat, fatigue and headache.

Given the likelihood of an early flu season, Li suggests that the public get vaccinated as soon as possible and prepare essential medications in advance. Those who suspect they have the flu should get tested and begin antiviral treatment early to prevent spreading the virus to family members and reduce the risk of severe illness.

Jiang Jianmin, a researcher at the Zhejiang Provincial Center for Disease Control and Prevention, said during a recent news conference that individuals age 60 and above, those with chronic diseases, and infants and children over 6 months old are key groups for flu vaccination.

"Healthcare workers, staff workers at nursing homes, child care centers and social welfare institutions, as well as people living with infants under 6 months old, are also among the priority groups for vaccination," she added.

wangxiaoyu@chinadaily.com.cn