About 33.4 million doses of vaccines have been approved for use as of Saturday, 26 million of which have been dispatched to local medical institutions.

Vaccination was one of the effective ways to prevent flu spreading, but seasonal flu vaccines would not help protect people against the A/H1N1 flu, experts said.

Calculating on their existing production capacities, the eight domestic vaccine manufacturers are expected to produce a total of 100 million doses of A/H1N1 flu vaccines by the first quarter of next year, according to the ministry.

But for now, about 390 million people on the Chinese mainland needed inoculation. Targeted groups included the People's Liberation Army (PLA) and armed police forces, police, medical staff, teachers, students, people working at key public service posts, and patients with chronic or cardiovascular diseases, experts said.

Children under the age of three and pregnant women are not included in the targeted groups due to lack of clinical data, said the ministry, adding that relevant departments are considering to carry out clinical tests.

Currently, youngsters are the high risk groups of the flu, Liang said.

As of Oct. 31, more than 1,500 cases of mass infection have been reported on the Chinese mainland, 98 percent of which were related to schools, according to the ministry.

The Chinese mainland has now 411 laboratories and 556 hospitals engaging in monitoring flu cases.