China's Ministry of Health (MOH) has launched an investigation into a report that defective vaccines had killed or sickened almost 80 children in north China's Shanxi Province, said a statement on the ministry website Wednesday.

The ministry had asked the provincial health authorities to report abnormalities caused by the vaccines as soon as possible, the statement said.

Field investigations by reporters found that encephalitis, hepatitis B, rabies and other vaccines had killed four children and sickened at least 74, the China Economic Times newspaper reported Wednesday.

The report said that Shanxi Province had been selling problem vaccines since 2006, causing viral encephalitis after vaccination, and provided the names and information of 15 ill children.

The report accused Shanxi Center for Disease Prevention and Control of exposing vaccines to heat in summer causing quality problems.

Earlier reports of defective vaccines had prompted the MOH to conduct a joint inspection with the State Food and Drug Administration in November 2008. Random samples were tested, but no quality problems were found, the statement said.

Li Shukai, deputy director of Shanxi Health Department, denied the accusations and said the report was "basically not true."

He said the provincial health authorities already investigated into some cases mentioned in the report, when they first surfaced in 2007.

"After thorough appraisal and examination, the provincial expert team believed that they were not abnormalities caused by the vaccines," he said.

Li said the Shanxi Health Department is investigating the cases of the 15 ill children named by the China Economic Times.

MOH investigations in November 2008 showed that from January 2006 to November 2008, 11 children reported discomfort after vaccination in Shanxi. Among them, six were identified as normal reaction. Four abnormal reactions were diagnosed as irrelevant with vaccines. The only case of vaccine-related abnormality was not caused the vaccines mentioned in the reports, according to the MOH statement.

(Xinhua News Agency March 18, 2010)