Vaccines are adequately refrigerated at a community health service center in Xiacheng district, Hangzhou, March 22. [Photo/VCG]

Vaccines available for private purchase are also important for children's health.

In fact, there are some vaccines currently only available on the private market in China, which WHO recommends be included in the national immunization program – including for pneumonia/meningitis, pneumococcal, and rotavirus.

This would ensure that all children in China would benefit from the use of these vaccines, and have the benefit of bringing them into the more tightly managed government distribution system.

The ongoing investigation by health authorities and the police into China's vaccine reselling ring shows how seriously the Chinese government is taking this incident.

WHO is in close contact with the health authorities as they conduct their investigation, and have offered our full support.

Ultimately, though, this incident has highlighted the need for much stricter enforcement of vaccine management regulations across the board.

Specifically, the same high standards used to distribute EPI vaccines should be used in the distribution of privately-purchased vaccines.

This would ensure that the activities which sparked the current investigation would never be able to happen again.

One of the problems with the current events is the risk that parents' confidence in immunisation will be diminished, and they will decline routine vaccination of their children.

This would be a terrible outcome – because vaccines are the only way to prevent a range of debilitating, deadly childhood diseases.

Improving management, monitoring and oversight of privately purchased vaccines in China is crucial to ensure the safety and effectiveness of all vaccines.

Urgent action to achieve is needed to restore the public's trust and confidence in vaccines in China, and to keep China's children healthy.

The author is World Health Organization representative in China.