A mother and daughter from East China's Shandong province have since 2010 allegedly sold vaccines worth 570 million yuan ($88 million) illegally in China, said the police on Friday.

The police department in Jinan, Shandong's capital city, confirmed an earlier report by The Paper, a Chinese news organization, showing that the not adequately refrigerated vaccine could leave them ineffective and put the lives of the users at risk.

The police said they have already started to trace all the children and adults in 18 provinces that used the suspect's vaccine in order to give them the correct medications.

The mother and daughter, who are surnamed Pang and Sun have been prosecuted on the suspicion of illegal trading.

Pang, a 47-year-old former doctor in Shandong's Heze city, was sentenced to three years in prison with a five year probation for illegal trading the vaccine in 2009, the police said.

Vaccines are required to be refrigerated between two and eight degree centigrade. The temperature in Pang's storage in her home, where she hid more than 100 packs, more than 20000 does, vaccines for diseases including meningitis, poliomyelitis and rabies was over 14 degrees.

In 2014, a 63-year-old farmer died from rabies one month after being injected with ineffective rabies vaccine.