BEIJING - A government health official said that no substantial mutations have been detected in the strains of influenza virus currently circulating throughout the country.

Shu Yuelong, director of the Chinese National Influenza Center affiliated with the Ministry of Health, said at a Wednesday press conference that this season's flu vaccine is still acceptable for use against the virus strains currently in circulation.

Information collected from China's influenza monitoring network has revealed an increase of flu cases since January this year, with the number of cases currently at its peak level, Shu said.

However, Shu said the total number of cases remains within an acceptable range.

Shu said influenza B is the most predominant flu strain in China this year.

Also at the press conference, Wang Yu, director of the Chinese Center for Disease Control and Prevention under the Ministry of Health, said there should be "no compromise" in China's efforts to control tobacco.

"I think research and techniques that are aimed at making cigarettes less harmful, such as adding traditional Chinese herbs to cigarettes, are just a waste of resources," he said.

Wang added that his comments were not a reference to Xie Jianping, a researcher known for his research on low-tar cigarette studies.

Xie, who serves as the deputy head of a tobacco research institute under the China National Tobacco Corporation, came under fire by Chinese netizens late last year after being honored with a seat in the elite Chinese Academy of Engineering.