Sales records of vaccines. [Photo: Agencies]

Police in China have confirmed 130 people have now been detained in the current vaccine trading scandal in China.

The Ministry of Public Security says a total of 69 criminal cases have been filed nationwide.

Meanwhile, health officials are now trying to trace the flow of a large quantity of improperly stored or expired vaccines had been sold in more than 20 provincial-level regions since 2011.

So far 29 different pharmaceutical companies are being accused of some form of involvement in the selling the illegal vaccines.

The issue first came to light after two people were busted in Shandong earlier this month attempting to sell black-market vaccines to hospitals.