African swine fever is highly fatal to pigs and has no known cure — yet a private company in southern China claims to have found an effective “vaccine” that it’s hoping to mass-produce.

Highsun Group, a listed company based in Guangdong, disclosed on the Shenzhen Stock Exchange Tuesday evening that a team of scientists on the island province of Hainan had successfully developed a vaccine against African swine fever — a claim that has raised doubts among authorities and the general public. Highsun said it will sign a 900 million yuan ($130 million) contract to develop and mass-produce the vaccine.

Described as a “jinzhu polysaccharide injection,” the vaccine is over 92% effective, according to the disclosure. Though Highsun has not yet signed an official contract with the vaccine’s developer, the company said it plans to do so by mid-2020, and to establish a production base in Hainan for making 1 billion doses of the vaccine annually.

Despite the efforts of epidemic prevention experts around the world to develop and test vaccines against African swine fever, there is currently no product that can stop the highly contagious, highly fatal disease. Over the past year, it has spread to every province of China — the world’s leading pork supplier — resulting in over 1.2 million pigs being culled. An effective vaccine would prevent further economic losses and guarantee huge profits for its developers. In its disclosure, Highsun estimated post-production windfalls of 200 million yuan in 2019 and 2 billion yuan by 2021.

But doubts abound over whether Highsun’s vaccine is indeed effective and ready for use. Though the company calls its creation a “vaccine,” Han Runlin, a professor at Inner Mongolia Agricultural University, told Shanghai Securities News on Thursday that, judging by the product’s name, it appears to be an herbal extract rather than a vaccine: According to local media, the product’s ingredients are derived from “multiple tropical plants.” Furthermore, Shanghai Securities News quotes an unnamed Highsun employee as saying that the vaccine is merely a “Chinese herbal medicine injection.”

“Certain Chinese herbs could have inhibitory effects on influenza,” Lu Mingzhe, an official at the China Animal Health and Epidemiology Center, told Sixth Tone on Thursday. But Lu said that in the absence of empirical data, it would be premature to comment on the efficacy of Highsun’s product.

The vaccine’s inventor has also been called into question. Highsun claimed that Xu Qitai, the project’s head scientist, had registered a patent for the vaccine. However, Sixth Tone’s search on China’s online patent registry returned no results for African swine fever-related patents under Xu’s name. Instead, Xu’s patents mostly deal with betel nut, an addictive plant that is chewed like tobacco and linked to several cancers. Previously a pharmacy professor at Henan University, Xu is now the chief director and major shareholder of Hainan Green Areca Technology Development Company, which produces a variety of betel nut-derived products.

On Tuesday, a representative from Jinzhu Agricultural Development Company, which Xu founded this year to produce the vaccine, told The Paper, Sixth Tone’s sister publication, that the product is still “in the experimental phase.”

While Highsun’s disclosure referred to receiving “support from related government departments in Hainan” to build a production facility, whether local authorities have approved the vaccine or authorized its production remains a mystery. Hainan’s office of agriculture and rural affairs published a notice this week acknowledging the “preventive effects” of the vaccine in “preliminary clinical trials.” However, an official from the office told The Paper that they had given no such endorsement and were looking into the source of the news.

On Thursday morning, the Shenzhen Stock Exchange issued an inquiry letter to Highsun requesting the company’s source for its efficacy claims as well as the vaccine’s patent details. Meanwhile, the central Ministry of Agriculture and Rural Affairs has ordered its provincial office in Hainan “make an announcement on the issue.”

On each of the two days since Highsun’s disclosure, the company’s stock price rose by 10%, the daily maximum for exchanges on the Chinese mainland. On Thursday, Highsun closed at 3.47 yuan per share.

Correction: A previous version of this story incorrectly stated when the Jinzhu Agricultural Development Company was founded.

Editor: David Paulk.

(Header image: Farm workers administer injections to pigs in Zhuji, Zhejiang province, March 21, 2013. VCG)