BEIJING - A cross-departmental team will investigate the recent case of improper vaccines trading, Xinhua learned Monday.

The group, established by the State Council, will be led by Bi Jingquan, head of the China Food and Drug Administration (CFDA). Senior officials from the National Health and Family Planning Commission, the Ministry of Public Security, Ministry of Supervision and the CFDA are deputy heads.

Officials from the Publicity Department of the Communist Party of China Central Committee, Cyberspace Administration of China and the Supreme People's Procuratorate are also in the team.

The State Council has also formed a supervision team to oversee the investigation.

A large quantity of improperly stored or expired vaccines have allegedly been sold across the country since 2011. Twenty-nine pharmaceutical companies have been implicated in sales, and 16 institutions in purchases. More than 130 people have been questioned and 69 criminal cases have been filed.

Bernhard Schwartlander, World Health Organization (WHO) representative in China, called the national immunization system "one of the best in the world" in an interview with Xinhua on Monday.

The WHO has confidence in all Chinese vaccine manufacturers, based on over 15 years of working closely with the national vaccine regulators, Dr Schwartlander said, pointing out that the biggest risk is that parents might avoid routine vaccination of their children as a result of diminished confidence in the system.

He called for urgent action to restore public trust.