New Covid variants threaten China’s mRNA vaccine hopes

China is making progress in efforts to develop a homegrown messenger RNA Covid-19 vaccine, but experts warn that it risks being outpaced by rapid mutations of the Omicron coronavirus variant.

Beijing’s refusal to approve foreign jabs, and the limited effectiveness of the more traditional inactivated vaccines available from domestic companies, mean an mRNA vaccine is widely seen as essential to any shift away from President Xi Jinping’s economically costly zero-Covid policy.

Optimism among analysts about the prospects for Chinese mRNA vaccines has been fuelled by recent trial results for a jab developed by start-up Suzhou Abogen Biosciences with Chinese pharmaceutical company Walvax Biotechnology and the country’s military.

According to results published in May, Abogen’s AWcorna vaccine generated antibodies against Omicron at levels 4.4 times higher than those induced by the inactivated vaccine produced by Sinovac, one of China’s two main vaccine suppliers.

Abogen’s early data “looks very positive”, said Ben Cowling, an epidemiologist at the University of Hong Kong.

Most of the Chinese public has been vaccinated with inactivated vaccines from Sinovac and state-owned Sinopharm. Researchers have said this technology produces a weaker immune response than mRNA vaccines, which target the virus’s spike protein.

In an effort to increase vaccine take-up, health officials in Beijing on Wednesday announced that the capital’s 21mn people would from next week for the first time have to show evidence of Covid vaccination to enter public spaces such as cinemas and gyms.

Helen Chen, head of China life sciences at LEK Consulting, said Abogen was “the closest to completion” of nine mRNA vaccine candidates developed by or in partnership with Chinese pharmaceutical companies and undergoing clinical trials.

Success for Abogen could have implications beyond the country’s borders.

The company hopes it will be possible to store its jab at normal refrigerator temperatures, rather than requiring the specialised low-temperature equipment needed for the mRNA vaccines produced by Moderna or BioNTech and Pfizer. That would make it much easier to distribute in developing nations.

But experts said Abogen and other Chinese mRNA jabs were also designed for earlier variants of Covid, and might struggle to cope with the emergence of newer BA.4 and BA.5 Omicron subvariants. These strains have found ways to sidestep natural and vaccination-generated immunity and are quickly becoming dominant across much of the world. Studies have shown that more fully vaccinated people have been infected with BA.4 and BA.5 than with earlier strains.

“There is a huge learning curve when it comes to mRNA technology, and the companies have to contend with a moving target with all these Covid strains,” said James Bellush, a medical sciences expert at New York-based RTW Investments.

Bellush said the emergence of new variants meant that Chinese mRNA jabs would certainly not have the “earth-shattering” effectiveness against infection of the Moderna and Pfizer jabs when they were first introduced in 2020. It was also not clear how much Abogen’s vaccines might protect recipients from developing severe Covid symptoms.

“The lingering question around Abogen is whether it will prevent severe disease. We haven’t seen the data yet,” Bellush said.

Abogen, which last year raised $1.1bn from investors including Singapore investment fund Temasek and Chinese private equity group Hillhouse Capital, is also carrying out early-stage trials of an mRNA vaccine candidate that targets the BA.4 subvariant on animals, according to one person familiar with the company’s work. Abogen declined to comment.

Covid-19 mutations have also plagued western pharmaceutical companies. But with vaccines that have already been in use for a year and a half, western biotech groups have a head start in adapting to new variants. Pfizer and BioNTech have said their Omicron-targeted vaccines elicit a strong immune response against the variant, outperforming their previous jab.

Creating any mRNA vaccine remains highly challenging. Bruce Liu, head of the life sciences division for China at the consultancy Simon-Kucher & Partners, said that among the biggest difficulties was developing lipid nanoparticles, the fatty shield that protects fragile mRNA molecules while they enter human cells, and which are hard to produce safely in large quantities.

“The devil is in the detail with mRNA,” Liu said.

Nor has all of Abogen’s trial data been encouraging. About one-third of 300 trial participants developed a fever after receiving AWcorna, compared with only 4 per cent for those who had a Sinovac booster. By comparison, 18 per cent of recipients in a separate trial who received the Pfizer jab developed a fever.

A higher incidence of side effects could make it more difficult for health authorities to convince vaccine-hesitant people to come forward for the shot — a particular issue in China, where sluggish take-up by the elderly has entrenched authorities’ commitment to lockdowns and mass testing.

Problems with homegrown mRNA vaccines could fuel calls for Beijing to turn to foreign jabs. Even before BioNTech announced its partnership with Pfizer, it agreed an alliance with China’s Fosun Pharma in March 2020 to supply any successful Covid mRNA shot. But more than two years later, Beijing has not approved any mRNA product for therapeutic use on the mainland.

Analysts said this reluctance was politically motivated, in line with Xi’s goal of reducing reliance on foreign knowhow in science and technology.

“China is allowing its domestic players to catch up, but this could prove to have been a big tactical mistake,” said one industry insider in China who did not want to be named.

Even if China manages to roll out a homegrown mRNA vaccine that is more effective in preventing serious illness, experts said Beijing’s determination to defeat the virus might make it unwilling to relinquish zero-Covid restrictions that have caused a slump in consumer spending and rising unemployment.

“There is no vaccine technology available that can prevent an infection wave if China relaxes public health measures,” said Cowling. “It would be hard for China to change course. There is so much momentum behind zero-Covid.”

Additional reporting by Nian Liu and Arjun Neil Alim in Beijing and Wang Xueqiao in Shanghai