China is approaching the approval of its first mRNA vaccine to protect people from COVID-19. In a small clinical study, a Chinese vaccine has provoked a strong antibody response in vaccinated adults when given a stronger than a jab containing the inactive SARS-CoV-2, a vaccine the country relies heavily on so far. The test jab, called ArCoV, is a strong candidate for China’s first mRNA vaccine. But what it could mean for the government’s response to the epidemic is difficult to determine, say researchers. A highly effective mRNA vaccine can reduce the risk of the spread of serious diseases that can infect hospitals. However, there is little chance of eradicating the country’s solid ‘zero COVID’ strategy, which uses mass testing and road closures to eradicate all diseases.
To date, China’s drug regulator has approved seven vaccines for COVID-19. Most Chinese nationals have been vaccinated with one of the two inactive viruses, CoronaVac, developed by a Beijing-based company, Sinovac, or BBIBP-CorV, developed by state-owned company Sinopharm in Beijing. Non-invasive vaccines are effective in reducing the risk of hospitalization and death1, but they provide less protection than the two mRNA vaccines developed by Pfizer-BioNTech and Moderna, widely used outside of China. “From the data of all the COVID-19 vaccines available in the world, mRNA technology looks better compared to other technologies,” said Feng Gao, a gynecologist at Jinan University in Guangzhou, China.
Imported vaccine
Chinese companies were planning to introduce a mRNA vaccine developed by BioNTech and Pfizer. As of March 2020, Shanghai-based drug company Fosun Pharma has entered into an agreement with BioNTech to sell the vaccine in China and Hong Kong once regulators have approved the product. But the approval of a highly effective vaccine is still pending in a large country, despite data from a Phase II study in China showing that the vaccine stimulates a strong immune response and is safe for use in adults. The reasons for the delay are unclear, but it could be political, said Yanzhong Huang, a Chinese health policy expert at the New York City Foreign Relations Council.
The Chinese government has approved foreign clinical trial data to speed up drug authorization processes from 2017. And urgently needed drugs, such as vaccines during the epidemic, may receive immediate revisions. “There is no other reason to explain the delay other than techno-nationalism,” Huang said. He also added that the Chinese government is probably choosing its first mRNA vaccine to be a home-grown dog like ARCoV.At least six local mRNA vaccines are in clinical trials. The ARCoV, developed by Suzhou-based biotechnology startup, Abogen Biosciences, is the lead, and is currently being tested in phase III, in a multidisciplinary trial in Mexico and Indonesia.
A small ARCoV trial, published as preprint3 on May 31 and not yet reviewed by peers, involved 300 adults in China who had received 2 doses of an inactive viral vaccine 6 months before receiving a booster. Investigators found that after the shooting of ARCoV, the immune levels that attacked Omicron were four times higher than the booster containing CoronaVac. Neutral antibodies can stop the virus from infecting a cell, and its levels are thought to be associated with the protective effect of vaccines.
“The results show a significant increase in mRNA vaccine compared to an inactive third-dose vaccine,” said Ben Cowling, a dermatologist at the University of Hong Kong. However, although previous research has shown that mixing vaccines can provide a strong immune response4, “without comparing these different side-enhancing strategies, it is difficult to say which vaccine is best”, says Gao. Whether the ARCoV vaccine “will receive official approval will depend on the results of the phase III trial. Not everyone who vaccines for mRNA will be successful, ” said Gao. If approved, ARCoV could be used both as part of the global vaccination program COVID-19 and as a guarantee, he adds.
Studies have shown that booster shots are important in protecting individuals, especially the elderly, from serious illness and death if they are infected with Omicron5. But in China, only 60% of people 60 years and older have received a booster shot, meaning that 100 million people in that age group have never. Booster installation is very low for those aged 80 and over – less than 20% of them received a booster shot in March, when the Omicron wave began to rise.
Gao says it is difficult to say whether uninvited people can accept the approved mRNA vaccine, as the technology is new. “But from a scientific point of view, it should, because mRNA vaccines often trigger a strong immune response, especially in high-risk individuals,” he adds. In many countries, increased availability of the COVID-19 vaccine has prompted governments to decide to open and reduce movement restrictions, reduce bulk testing and relieve segregation requirements. But researchers say that despite the highly effective mRNA vaccine, Chinese officials are unlikely to change their zero-COVID pathway, which has been able to contain a large number of outbreaks, but have not been as successful as Omicron’s highly contagious variants.
Source Journal Reference: Yvaine Ye, China’s first mRNA vaccine is close — will that solve its COVID woes?, Nature News (2022) https://www.nature.com/articles/d41586-022-01690-3
