(CNN)China has said it is cracking down on a crime ring making "fake vaccines" for Covid-19 that has been running since September, state media report.
Police departments in Jiangsu, Beijing and Shandong have arrested more than 80 people involved in producing more than 3,000 fake Covid-19 vaccine doses, Xinhua News Agency reported.
Xinhua said China's Ministry of Public Security is investigating crimes related to manufacturing and selling of counterfeit vaccines "and the illegal practice of medicine and fraud under the guise of the vaccines."
Police found that since September 2020, those involved "have been making huge profits by fulfilling saline solution into injectors to process and make fake coronavirus vaccines and selling them at a higher price," the agency said.
China has been vaccinating its population with shots from two companies, Sinovac and Sinopharm, and both have also been rolled out in other countries, including Turkey.
Both companies initially said their vaccines were more than 78% effective, but late-stage trials of the Sinovac candidate in Brazil reported an efficacy rate of 50.38%.
Sinovac has stood by its vaccine, even as some countries have placed it under review and paused rollouts, but scientists have called on the company to release more data.
Sinopharm, the state-owned company whose vaccine was the first to be approved in China, said its product was 79.34% effective in trials.