A child receives measles vaccine at a vaccination site in Nanjing, east China's Jiangsu Province, Sept. 11, 2010. [File Photo: Xinhua]

The central government has established a cross-departmental working group to investigate the trade of improperly handled vaccines, a case that shook the country, Xinhua learned Monday.

The group was established by the State Council and is led by Bi Jingquan, head of the China Food and Drug Administration (CFDA).

Senior officials from departments such as the National Health and Family Planning Commission, the Ministry of Public Security, Ministry of Supervision and CFDA, are deputy heads of the group.

Officials from the Publicity Department of the Communist Party of China Central Committee, Cyberspace Administration of China, the Supreme People's Procuratorate also joined the work group.

The group also has an expert committee.

In the meantime, the State Council formed a supervision team to oversee and guide the investigation work, and will publicize timely supervision results.

The State Council said the scandal has exposed weaknesses in the vaccines distribution system.

The public were shocked by the news that a large quantity of improperly stored or expired vaccines had been allegedly sold in more than 20 provincial-level regions since 2011.

Twenty-nine pharmaceutical companies have been implicated in selling the illegal vaccines, and 16 vaccination institutions are suspected of buying them.

More than 130 people have been questioned and 69 criminal cases have been filed nationwide.