Vaccines confiscated. [Photo provided by the police]

The first category, under which residents are required to be vaccinated and there is no charge, may differ between areas.

Under the second category, the vaccines are not free and residents can choose whether they want to be inoculated.

According to Shandong police, the vaccines confiscated in the case include 25 types that fall under the second category. According to the suspects' account book, they were resold in 24 provincial areas.

Police said even though all vaccines involved in the case are made by licensed producers, their quality is questionable as they were not stored or transported under approved conditions.

The mother, 47, surnamed Pang, is a former doctor from Shandong. She and her daughter were detained by police on April 28 last year. They have been transferred to prosecutors who are preparing charges of illegal trading.