Primary school students are inoculated with A/H1N1 flu vaccine at Liuzhou, southwest China's Guangxi Zhuang Autonomous Region.

The A/H1N1 influenza was spreading rapidly across the country but it remained under control, an official with the Ministry of Health said Sunday.

"Currently close to 80 percent of the country's total flu infections are A/H1N1 flu cases, though the state of the flu was still mild and there was no evidence of virus mutation," Liang Wannian, deputy director of the Emergency Response Office of the Ministry of Health, said.

As of Saturday, more than 46,000 confirmed A/H1N1 flu cases had been reported on the Chinese mainland, 75 percent of whom had recovered. Among the 93 cases of serious condition, 55 were still in hospital, the ministry said. Chinese mainland has reported six deaths from the flu since Oct. 2.

Ministry experts warned that the flu has entered a period featured by high frequency and quick increase in the number of infected cases in the country, and it could last through March next year.

Liang urged health administrative departments across the country to "prepare for the worst and do the best".

He said, medical institutions and hospitals across the country are making preparations in terms of personnel, materials and technical support to cope with possible emergencies.

"China has taken a series of measures to prevent and control the spread of the flu, which proved to be effective, buying some time for the country to prepare for more serious epidemic situation," Liang said. "China's preventive measures have also greatly slowed down the spread of the flu and significantly reduced the deaths from the flu in the country."

As the first country in the world to issue a production license for vaccines against the flu, China had inoculated more than 3.78 million people as of Saturday, with no reports of serious adverse reaction, according to the ministry.

The vaccination is being carried out across the country except in Chongqing Municipality and the provinces of Anhui, Jiangxi and Sichuan.