Chinese laboratories are raising the alarm over a new potential danger to public health amid a massive wave of COVID-19 infections: a growing trade in fake antiviral medication.

China is experiencing a severe shortage of approved antivirals such as Paxlovid, manufactured by U.S. pharmaceutical giant Pfizer, which has opened the door to a thriving black market for COVID medication in recent weeks.

Boxes of Paxlovid are now selling for as much as 50,000 yuan ($7,200) on the black market, forcing many in China to seek out cheaper alternatives. That is driving a surge in demand for generic versions of the drug produced by Indian manufacturers.

However, laboratory analysis indicates that a large amount of the “Indian drugs” circulating in China are fake.

Though no evidence has yet emerged that the counterfeit drugs contain actively harmful ingredients, experts say they represent a serious public health risk, as the pills are ineffective against the virus and could delay patients from receiving real treatment.

China’s hospitals appear to have been ill-prepared for the surge in demand for COVID-19 medication triggered by the end of the country’s “zero-COVID” policy in early December.

China granted emergency approval to Paxlovid in February 2022, and to Merck’s Molnupiravir last week. It’s unclear how much of the drugs were imported, but by the end of December hospitals in several major cities were reportedly experiencing inventory constraints or even stockouts.

The black market quickly moved to plug the gap. There was already a huge trade in cheap, made-in-India medication in China before the pandemic. Thousands of Chinese cancer patients rely on illegal imports of generic drugs produced in India, as they are far more affordable than the approved drugs on sale in China.

Now, importers appear to have pivoted to selling Indian COVID drugs. On the Chinese e-commerce platforms Taobao and JD.com, at least four generic COVID drugs produced in India — Primovir, Paxista, Molnunat, and Molnatris — have been listed for sale in recent weeks.

Primovir and Paxista are both generic versions of Paxlovid, while the other two are generic versions of Molnipiravir. All four drugs appear to have been approved for emergency use by the Indian authorities, but are not legal for use in China.

After Chinese media began reporting on the growing trade, Taobao and JD.com quickly moved to take down stores selling the drugs. However, vendors have managed to keep selling them using workarounds, several users who have bought drugs via the platforms told Sixth Tone.

Some vendors post deliberately vague listings advertising their ability to source “generic drugs,” then connect with buyers and arrange sales via the social app WeChat.

The earliest warnings about counterfeit COVID drugs came from a blogger on the Chinese Q&A site Zhihu, who writes under the username Tianzhu 10 Years. On Dec. 14, the blogger claimed to have uncovered evidence that fake Primovir was being sold in China.

According to Tianzhu 10 Years, the box of Primovir he had purchased listed an Indian company named Astrica Healthcare as the manufacturer. But when he contacted the company’s director via WhatsApp, he was told that Astrica had stopped manufacturing the drug months ago.

“Primovir stock finished,” the director wrote, according to a screenshot of the conversation posted on Zhihu. “Now someone (is) making fakes.”

The blogger then said he had tested his Primovir pills using liquid chromatography, a technique used to identify the chemical components in a mixture. The results indicated that the drugs contained no Nirmatrelvir, a crucial component that is used to inhibit the virus’s proliferation in the body. He posted the test results to Zhihu on Dec. 21.

The post inspired a number of other buyers to send their black market COVID medication for testing at laboratories over the following days. Many produced similarly worrying results.

Yin Ye, the CEO of Chinese genomics company BGI Group, wrote in an article published on WeChat Dec. 31 that he had helped some friends test their medicine. Several samples sold under the brand name Primovir turned out to be fake: The pills did not contain Nirmatrelvir, but Oseltamivir, an antiviral drug used to treat flu viruses, Yin said.

“In the current situation where it is difficult to buy original drugs, one should be extremely careful when selecting COVID-19 generic drugs,” Yin wrote, adding that his company was willing to help people test their generic drugs free of charge.

In the days since, Yin has been posting updates on these tests to his feed on the microblogging platform Weibo. As of Friday afternoon, Yin’s team has tested 150 samples of medication sent in by the public.

Of 143 samples of Primovir, only one contained Nirmatrelvir. The other seven samples were sold under different brand names, and all of them contained Nirmatrelvir.

Yin’s post went viral on Chinese social media and triggered outrage among buyers, many of whom had spent thousands of yuan on packages of Primovir.

Shen Xin, a scientist based in the northern city of Tianjin, suspects that she is a victim of the fake drugs trade. She bought a box of Primovir from a friend after being unable to acquire Paxlovid.

“My father is 76 years old. He lives alone in Inner Mongolia,” said Shen, who spoke with Sixth Tone using a pseudonym for privacy reasons. “The medical resources there are in short supply. I worried about him not being able to get treatment in time if he caught COVID.”

Shen ran a test on her Primovir pills at a friend’s lab, which failed to detect Nirmatrelvir. But she has decided to send samples to BGI’s lab as well, hoping that the company’s more advanced equipment produces different results.

Other buyers are focusing on seeking refunds for the drugs they have bought. So far, it appears that vendors are often willing to give buyers their money back if they haven’t taken any of the pills, according to five buyers Sixth Tone spoke with.

Chen Zhi, a lawyer at the Shanghai United Law Firm, told Sixth Tone that scalpers selling unapproved Indian generic drugs could be charged with a serious criminal offense if the drugs are found to be counterfeit.

However, China has softened its restrictions on imports of unapproved Indian medication in recent years. Before 2019, anyone caught purchasing a drug unapproved for use in China could face tough punishments, but those penalties have since been scrapped.

Yet, by reducing the legal risks for buyers, the policy change paved the way for unprecedented flows of Indian-produced COVID drugs into China, said He Xiaobing, CEO of Beijing Memorial Pharmaceutical, a Chinese firm that specializes in coordinating clinical trials between China and India. That huge illicit trade also brings risks.

“India is a powerhouse in generic drugs. It’s the only country where we can source reliable and affordable COVID drugs with guaranteed therapeutic effects,” He said. “But the strong demand was used by illegal groups who produce counterfeit drugs. This will badly affect patients’ treatment.”

So far, there have been no reports of COVID patients developing unwanted symptoms after taking Primovir, but medical experts and doctors have warned the public against taking generic drugs from unknown sources.

Chinese authorities have been working to ease the Paxlovid shortage in recent days. Beijing, Shanghai, and Guangzhou reportedly started distributing the drug to community hospitals in January. The central government authorized some online hospitals to prescribe Paxlovid a month earlier, with patients only needing to upload a photo of a positive antigen test to get a prescription.

But patients say it’s still hard to access the drug.

“These platforms are replenished with new inventory every day, but the stock is too small,” a resident of the eastern city of Wenzhou, surnamed Jin, said. “I know someone who has been trying for two weeks without success.”

Jin bought a box of Primovir on Dec. 15 and sent the drug to Yin for testing on Jan. 1. She received the result a day later: It was fake.

Now, Jin regrets wasting two weeks believing she’d already secured “life-saving drugs” for her 90-year-old grandfather.

“I could have spent more time trying to order real Paxlovid from the online hospital,” Jin said.

Editor: Dominic Morgan.

(Header image: Visuals from @凯喜博士DrCash on Weibo and 500px/VCG, reedited by Sixth Tone. The team has tested the contents of over 50 COVID drug samples sent to them by their followers over recent days. As of Jan. 5, around 90% of the samples did not contain Nirmatrelvir.)