A Chinese drug company is under investigation after it was discovered to have sold more than a quarter-million doses of sub-standard vaccines for infants.

Changchun Changsheng Life Sciences Limited sold the diphtheria, pertussis, and tetanus (DPT) vaccines to the Shandong Centre for Disease Control and Prevention, which serves the Shandong province’s population of nearly 100 million, and many were administered to children as part of China’s nationwide mandatory vaccination program, CNN reported.

The pharmaceutical company also allegedly changed its rabies vaccine production method and created fake production and inspection records. 

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The government has since revoked Changsheng’s license to produce rabies vaccines for humans, and five of the company’s top executives, including its chairwoman, are now under criminal investigation, NPR reported. 

Changsheng — which means “long life” — has also been fined approximately $500,000 (3,442,887 yuan).

Issues with Changsheng’s rabies vaccines were first discovered earlier this month after authorities were tipped off and conducted a spot check of the product, Xinhua, a state-run news agency, reported.

President Xi Jinping called the sale of faulty diphtheria, pertussis, and tetanus (DPT) infant vaccines “vile and shocking,” CNN reported. And public outrage has been mounting on Chinese social media outlets, the South China Morning Post reported.

Premier Li Keqiang said in an instruction that the #vaccine case has crossed a moral line, and the nation deserves a clear explanation, the #StateCouncil said on its website on Sunday. pic.twitter.com/GUmpYkRXEQ

— China Daily (@ChinaDailyUSA) July 22, 2018

But even more concerning is the increasing doubt over the integrity of China’s health care system and medical industry.

"My home country, how can I trust you? You just let me down again and again," one user said of the incident, according to CNN.

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The Changsheng vaccine scandal is just one of several scandals in which Chinese drug manufacturers have been accused of producing fake or defective vaccines and medicines in recent years. Just last year, another Chinese pharmaceutical company was discovered to have produced and sold more than 400,000 ineffective DPT vaccines to provincial public health agencies, according to the South China Morning Post. The drug manufacturer at fault has yet to face consequences for the fake vaccines.

The Changsheng investigation not only comes at a time when the country had set its sights on becoming a global leader in pharmaceutical production, but has contributed to mistrust of China’s medical system and vaccines among parents.

And while some parents told the South China Morning Post that they will only allow their children to be administered vaccines produced overseas or will take their children to nearby Hong Kong for vaccinations, those who cannot afford to do so may simply stop vaccinating their children.

Effective vaccinations are vital to protecting children against many life-threatening diseases, according to the World Health Organization. And vaccines not only offer protection to immunized individuals but can help prevent the spread of illnesses. More than 1.5 million children die every year from vaccine-preventable diseases, according to UNICEF.

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People and children living in poverty tend to be the most affected by such illnesses due to a lack of access to vaccines and adequate health care. 

Experts worry that the recent scandals will lead Chinese families to forgo vaccines, despite legal immunization requirements, and that the current crisis of confidence in the quality of China’s medical care will take years to address.

“This incident could become a public health crisis should it not be handled in a reasonable and transparent manner,” an editorial in China Daily, a state-run paper, said. “The government needs to act as soon as possible to let the public know it is resolved to address the issue and will punish any wrongdoers without mercy.”