The avian influenza strain of H7N9 is highly likely to return and affect humans in the autumn and winter on the Chinese mainland, warned Zeng Guang, chief epidemiologist at the Chinese Center for Disease Control and Prevention.
China has remained free of new human H7N9 cases for more than a month since the last fatality - a 51-year-old woman who died of multiple organ failure caused by the virus on Aug 12 in Huizhou, Guangdong province - according to the National Health and Family Planning Commission.
The woman, who was transferred from Langfang, Hebei province, in mid July, worked in slaughtering poultry at a local market.
China has reported 134 human infections of H7N9 on the mainland, including 45 deaths, official statistics show.
"Given that the virus never stopped circulating among birds, humans are also at risk of infection, particularly in the common peak flu season, which usually lasts till spring,"Zeng said.
An overlap of the peak flu season and more frequent smoggy weather could make the situation even worse and intervention efforts more complicated, he said.
Flu prevention requires good ventilation, which can't be easily supplied in smoggy weather, he explained.
He urged the public to take precautions such as to avoid staying in public places for long and to be aware of good personal hygiene, including frequent hand-washing.