China's annual COVID-19 vaccine production capacity is expected to reach 610 million doses by the end of this year and more than 1 billion doses in 2021, an official from the National Health Commission (NHC) announced on Sept. 25.

Zheng Zhongwei, director of the Development Center for Medical Science & Technology of the NHC, said that COVID-19 vaccines will be offered at affordable prices for China's general public.

"There is a unified guiding price for emergency use. Once the vaccines enter the market, prices will be adjusted according to technical routes, scale of use, and other factors," Zheng said, adding that the vaccines would be available, affordable, and accessible.

Wu Yuanbin, director of the Department of Science and Technology for Social Development of the Ministry of Science and Technology, said, "At present, China's COVID-19 vaccine research and development work is in a leading position overall. Eleven Chinese-developed vaccines have entered clinical trials, among which four have entered phase III clinical trials."

So far, two inactivated vaccines produced by China National Biotec Group have been administered to more than 35,000 people during phase III trials in the Middle East and the results have shown no severe adverse reactions, Wu said.

Sinovac, another vaccine producer, has also been carrying out phase III trials of its inactivated vaccine in South America and Southeast Asia, Wu continued.

Meanwhile, an adenovirus vector vaccine jointly developed by the Academy of Military Medical Sciences and CanSino Biologics has been approved for phase III trials in Eurasia, Wu said.

Potential vaccines developed through other technical routes, including recombinant protein vaccines, nucleic acid vaccines (mRNA, DNA), and attenuated influenza virus vaccines, are currently being trialed in phase I or II, Wu added.

In response to concerns about virus variation, Zhang Xinmin, director of the China National Center for Biotechnology Development, said that the novel coronavirus has not shown significant variability.

Additionally, the current mutations have not had a substantial impact on vaccine development and the immunity produced by vaccine candidates can effectively neutralize a mutated virus, Zhang said.

Zeng Guang, chief epidemiologist of the Chinese Center for Disease Control and Prevention said more long-term research is needed to know how long a certain vaccine will remain effective after administration.

"An encouraging result is that serum monitoring over China's first group administered with a COVID-19 vaccine indicates high levels of antibodies. This suggests that the vaccine may create a long-lasting immune response," Zeng said.

However, Zeng noted that the protective power of a COVID-19 vaccine can only truly be defined after phase III clinical trials.