The chairwoman of a rabies vaccine producer under fire for fraudulent quality controlis among 15 people arrested by Chinese authoritieson "suspicion of criminal offences" over a vaccine scandal.

The development came late on Tuesday, days afterpharmaceutical manufacturer Changchun Changsheng Biotechnology admittedto falsifying test results and producing fake vaccines.

Police in the northeastern city of Changchun announced the arrests but did not give the chairwoman's full name. She has previously been identified as Gao Junfang.

The China Food and Drug Administration (CFDA) said last week the problematic rabies vaccine had not left Changsheng's factory, but the company admitted it had shipped a separate, sub-standard vaccine.

While there have been no apparent reports of people being harmed by the vaccine or having contracted rabies after receiving it, the regulator has already ordered Changsheng to halt production and recall all its vaccines.

High-level unease

Authorities have announced a series of investigations, vowing that heads would roll.

In a sign of the high-level unease, President Xi Jinping - on a trip to Africa - weighed in on Monday, calling the vaccine company's actions "vile in nature and shocking", according to state media.

The affair has shattered already fragile trust in regulators and spotlighted the frustrations of China's increasingly sophisticated consumers, who took to social media en masse to vent their anger over the case.

By Monday, shares in Chinese vaccine makers and biotech firms had fallen across the board.