The food and drug administration of East China's Shandong province on Monday made public a list of problematic vaccines illegally sold in 18 provinces since 2011.

The 12 vaccines, 2 immune globulin and one therapeutic product were allegedly sold by a mother and daughter, who were arrested in Shandong.

China's drug regulator and police are trying to trace them, which are worth more than 570 million yuan ($88 million), and have given pharmaceutical companies and distributors involved a deadline of March 25 to come up with information about the whereabouts of the vaccines.

The two women were engaged in the purchase and sale of vaccines for a profit. Though produced by qualified manufacturers, the vaccines were not transported in approved conditions and so quality cannot be guaranteed. Such vaccines have potential side-effects and may even cause disability and death.

The case has been transferred to the procurators.