Ensuring all countries of access to COVID-19 vaccines in the future is a significant strategy to prevent the spread of the coronavirus around the globe, a top Chinese expert said at a forum held parallel to the Zhongguancun Forum (ZGC Forum) in Beijing on Saturday. 

Gao Fu, director of the Chinese Center for Disease Control and Prevention (CDC), said the vaccines can provide fundamental immunity, especially effective protection against severe illness or even death, although the coronavirus has been mutating and the efficacy of vaccines may drop in the face of different variants.

"The world needs to share the vaccines. Otherwise, the viruses will take over the world," Gao said.

China's zero-tolerance policy against COVID-19 is based on scientific evidence, Gao said, adding that the public has shown greater understanding and engagement when decisions are science-based. 

A total of 315 COVID-19 vaccine candidates are in development globally, of which 194 are in pre-clinical development and 121 in clinical trials, according to the World Health Organization (WHO)'s COVID-19 vaccine tracker and landscape published on September 24.

China has 24 COVID-19 vaccines in clinical trials, of which nine have entered phase-3 clinical trials, four have been granted conditional marketing approval, two have been included in the WHO Emergency Use listing, and three have been authorized for domestic emergency use in the country, Zhang Yudong, vice minister of Science and Technology, said at the same forum.

Experts also shared the latest development of some of the homegrown COVID-19 vaccines.

Xia Ningshao, director of the National Institute of Diagnostics and Vaccine Development in Infectious Diseases at Xiamen University, introduced the country's first intranasal spray version of the COVID-19 vaccine.

Xia said the immune response can be triggered 24 hours after a single dose of the nasal-spray vaccine, which can meet the needs of rapid emergency response. The protective effect can last for a long time after two doses, and it is effective for the elderly as well.

Wei Yuquan, director of the National Key Laboratory of Biotherapy at West China Hospital of Sichuan University, elaborated on a domestically developed COVID-19 recombinant protein vaccine.

The vaccine is made from recombinant proteins extracted from insect cells, known as sf9. It has finished the first two phases of clinical trials, and the phase-3 studies are underway, said Wei, adding that vaccines produced using the insect cell expression system are safe.

"Now that the virus is mutating, vaccination has bought us time," said Yin Zundong, director of the National Immunization Program of the China CDC.

"One of the things we need to do next is continuing to increase vaccination rates by covering more people and monitor adverse events at the same time," said Yin, adding that further research is underway on vaccination in younger age groups, as well as on booster vaccination.