Medical workers administer COVID-19 vaccines to college students in Nanchang, capital of East China's Jiangxi Province, June 4, 2021. Photo: Xinhua

The Chinese central health authority will promote the best combination of vaccines to enhance herd immunity, said Zheng Zhongwei, Director of the Development Center for Medical Science and Technology of the National Health Commission (NHC) and head of the national working group for vaccine development, noting that the country had 13 COVID-19 candidate vaccines on phase III clinical trials.

We believe that booster shots have good efficacy in preventing variants and reducing hospitalizations and deaths regardless of the type of shot administered previously, Zheng told China Central Television (CCTV) on Monday.

China launched research and development initiatives on COVID-19 vaccines through five methods. 

According to Zheng, 13 COVID-19 vaccine candidates have entered Phase III clinical trials. Three of them were approved for emergency use and four went to the market with conditions.

China started to roll out mass vaccination since last December. 

As of Monday, nearly 2.4 billion doses of COVID-19 vaccines had been administered on the Chinese mainland. 

In total, 4 billion shots developed by Chinese manufactures have been produced with 1.7 billion doses shipped overseas, Zheng told CCTV. 

Zheng revealed that a key problem for China's mass vaccination lies in the comparatively low vaccination rate of the elderly while this age group faces higher infection risk than younger people.  

"Only by accelerating the vaccination rate of the elderly and laying out booster shots can we really reduce the incidence of severe cases and deaths," Zheng said.

The total toll of deaths in the world caused by COVID-19 had exceeded 5 million with an average age of 70 years old. The risk of death for people aged 65+, 75+ and 85+ is 90, 220 and 570 times higher respectively than for younger people. Unless there is an allergic reaction to vaccines or an acute phase of disease, the elderly should also get vaccinated, Zheng noted.  

Meanwhile, Chinese companies are also conducting clinical trials on the efficacy and safety on young people while also expanding production capacity to meet global demand.

One of the major Chinese COVID-19 vaccine providers, Sinovac Biotech, is collecting data on overseas clinical trials on children aged between 6 and 17, CCTV said.

Sinopharm, another major manufacturer, can produce about 7 billion shots per year.