China is likely to realize herd immunity by the end of 2021 with its world-leading vaccination speed, Shao Yiming, chief expert at the Chinese Center for Disease Control and Prevention, said during an interview with CCTV on Tuesday.

To realize herd immunity, the term for when most of a population is immune to an infectious disease, China is aiming for a vaccination rate of 70 to 80 percent, or about 1 billion people, based on the basic transmission index for the novel coronavirus.

Shao, who is a member of China's COVID-19 vaccine research and development task force, said that some key areas have already been reached, while in areas with less containment pressure, such as inland regions where there is less international travel, vaccination is being carried out in an orderly manner.

According to the National Health Commission (NHC), China had administered a total of nearly 422 million doses of COVID-19 vaccines as of May 17 when over 15 million doses were dispensed – a single-day record. 

As of 9 a.m. Wednesday, over 15.57 million people in Beijing had been vaccinated, and over 80 percent of people aged 18 and above had received the first dose. The vaccination rate in industries including medical and healthcare, housing construction, urban management, postal express delivery, tourist attractions, hotels, and commercial has exceeded 90 percent, according to the municipal government.

"After a significant increase in our vaccine production capacity since the middle of this year, especially in the second half of the year, we will pace up vaccination," Shao said. "I believe we will be able to meet our target of establishing a herd immunity barrier by the end of this year."

The expert also assured that China has an adequate supply of COVID-19 vaccines, even in the face of sporadic cases in east China's Anhui Province and northeast China's Liaoning Province.

Administering some 12 million doses per day is considered a world record, but China has a larger potential, said Shao.

"We can administer as many as 20 million doses daily as long as there is demand."

Vaccines still effective against mutations

Viruses constantly undergo genetic changes, but small changes do not necessarily result in phenotypic changes – the epidemiological characteristics of the virus, severity of the disease caused by the virus, or association with vaccine escape, Shao explained.

For the variants of concern, the one first detected in the UK doesn't affect the efficacy of existing vaccines, he said. The variants detected in South Africa and Brazil are a bit more potent, but large-scale research in the real world shows the vaccines, whether mRNA or inactivated, are effective.

For the variant first identified in India, the mutations it has do not outnumber the other two, said Shao. Research by Indian scientists showed the two COVID-19 vaccines the country currently uses are effective.

The expert cautioned that vigilance and monitoring cannot be let down, but said China is closely tracking the situation and has the capability of responding to the mutants.

Shao explained that some vaccines, like the mRNA vaccine, have higher rates of protection in clinical trials, but the difference in protection is mainly for mild cases.

"We have also observed that the protection rate of all kinds of vaccines against severe cases, hospitalized admission, and death, is more than 80 percent. There's no big difference, which means the vaccines developed by different countries play a similar role in public health," he said.