By Monday, all 31 provinces and municipalities on the Chinese mainland had reported A/H1N1 flu cases, bringing the total to 5,592. So far, nearly 70 percent have recovered and no deaths have been reported.

Both the WHO and domestic experts say they believe the A/H1N1 flu epidemic will reach the peak in Autumn and Winter, Chen said.

He said China's situation was "grim" given the large number of students who started the new semester in September and the National Day celebrations.

In the past week, 95 percent of newly confirmed A/H1N1 flu cases were locals, he said.

A/H1N1 flu vaccine is formally put into production by China's domestic pharmaceutical company Sinovac Biotech Ltd., also known as Beijing Kexing Bioproducts, Sep.3, 2009. The State Food and Drug Administration (SFDA) issued the license for Sinovac's vaccine called Panflu.1, after it passed SFDA's experts evaluation on August 31. [Xinhua]

Since late-June, China has reported 128 cases of group infections. In some provinces there has been a rising proportion of A/H1N1 flu cases against other flu-linked illnesses.

On Friday, Shanghai reported an A/H1N1 flu patient showing severe symptoms, including respiratory and multi-organ function failures. On Sunday, eastern Zhejiang Province reported another patient in a critical situation with adult respiratory distress syndrome.

The Shanghai patient, though not completely out of danger, has shown signs of improvement, Chen said. The Zhejiang patient is also in a less critical situation.

A meeting presided over by Premier Wen Jiabao on Monday vowed to step up the prevention and control of the A/H1N1 flu virus in the run-up to the National Day celebrations.

Schools are currently the key battlegrounds in China's fight against the virus and classes would be suspended "properly" to avoid mass infection when an outbreak occurs, the meeting decided.

China's ability to produce A/H1N1 flu vaccines is still limited compared with its 1.3 billion population, Chen said.

"Therefore, we still need to carry out preventive measures proved effective previously, especially the public's ability to protect itself," he said.