A staff member tests samples of the COVID-19 inactivated vaccine at a vaccine production plant of China National Pharmaceutical Group (Sinopharm) in Beijing, capital of China, April 11, 2020.Photo:Xinhua

A groundbreaking ceremony for a COVID-19 vaccine production base was held on Sunday at Daxing Biomedical Industrial Base in southwestern Beijing. The vaccine will be based on the non-replicating viral vector using chimpanzee adenovirus, the first of its kind in China, media reported.

The vaccine to be made at the base was developed by Professor Zhang Linqi of Tsinghua University and Professor Zhou Dongming of Tianjin Medical University, and it will be produced by Walvax Biotechnology Co. Mass production is expected to reach 200 million doses per year by mid-2021, media reported.

"It is said that construction of the production base will be completed in half a year. That is reasonable because the production base of Sinovac Biotech Co was completed in less than half a year. Construction of Sinovac's workshop started in late February or March, when production was difficult due to the epidemic," a staffer of the Daxing Biomedical Industrial Base, who declined to be identified, told the Global Times on Sunday.

She said that the government of Daxing district was very supportive and gave the "green light" to Sinovac's vaccine base construction, and the Walvax production base will also face fewer administrative procedures. 

According to media reports, the viral vector vaccine candidate uses the adenovirus of a chimpanzee, the first of its kind in China.

Tao Lina, a Shanghai-based expert on vaccines, said that China's CanSino Biologics developed COVID-19 vaccine based on human adenovirus. "Both vaccines have advantages and disadvantages. Chimpanzee adenovirus has less affinity for humans, which will decrease the efficacy of entering human cells, while many people already have antibodies of human adenovirus, which will also affect the efficacy," Tao told the Global Times on Sunday.

There are 233 candidate COVID-19 vaccines in the world, of which 61 are under clinical development, according to statistics released by the WHO on Tuesday. Among the candidates in the clinical phase, nine are vital vector candidates, accounting for 15 percent, it said.

Last week, construction of the first mRNA COVID-19 vaccine manufacturing workshop started in the Yuxi High-tech Zone in Southwest China's Yunnan Province. The project is expected to be completed and enter operation within eight months, with a first-phase capacity of 120 million doses per year, the Xinhua News Agency reported.

China had six vaccine candidates in phase III clinical trials as of Tuesday, including the inactivated virus vaccine - one of Sinovac, one of the Chinese Academy of Medical Sciences and two of Sinopharm - the non-replicating viral vector vaccine of CanSino, and the protein subunit-based vaccine of Anhui Zhifei Longcom Biopharmaceutical, according to media reports.

Walvax Biotechnology could not be reached as of press time.