No "serious adverse reaction" has been reported in the tens of thousands of citizens inoculated with China-made A/H1N1 flu vaccines, the country's health minister Chen Zhu said on Monday.

He did not elaborate on the definition of "serious adverse reaction". Previously, Beijing had reported 14 cases of adverse reaction out of 39,000 residents inoculated.

Liang Xiaofeng, director of the immunization center under the Chinese Center for Disease Control and Prevention, told reporters at a news briefing on Sept. 23 that "the inoculations are safe, but the possibility of adverse reactions cannot be ruled out."

Liang said four of the 14 adverse reactions "may be" related to the vaccines and an investigation into the reasons was underway.

Liang also said there was still uncertainty about the safety of vaccination for "sensitive groups" such as pregnant and breastfeeding women.

The medical cost for A/H1N1 flu patients, especially for those suffering from heavy symptoms, will be compensated within the framework of the established medicare system, Chen Zhu said.

China is focusing inoculation on vulnerable groups such as students, teachers and patients of chronic diseases.

In response to possible adverse effects, China has established a system which enables local health departments to halt inoculation if serious cases like death or deformity occurred, or there appeared an apparent tendency of mass suspected cases of adverse reactions from A/H1N1 flu vaccines.

By Friday, among the more than 15,900 confirmed cases of A/H1N1 flu on the Chinese mainland, about 71.8 percent have recovered. There have been no deaths reported, according to the notice on the website of the Health Ministry.