China needs to vaccinate over 1 bn people to build immunity: Official

China needs to vaccinate more than a billion people in order to build an immune protection barrier against the COVID-19, a senior Chinese immunologist has said.

China, the world's most populous country, currently has five COVID-19 vaccines approved for conditional marketing or emergency use, and are free for the public use.

The higher the vaccination rate is, the stronger the immune barrier will be, Wang Huaqing, the chief immunologist at the Chinese Center for Disease Control and Prevention, said in an interview with state-run China Central Television (CCTV) on Sunday.

The novel coronavirus emerged at China's central Wuhan city in December 2019 and became a pandemic, upending the life across the globe.

The country has set itself a vaccination target of covering about 40 per cent of the population by around June, or about 560 million people and 1.1 billion doses.

As of Saturday, 164 million COVID-19 vaccine doses have been administered across the country, state-run Global Times reported on Tuesday.

According to past experiences, setting up a protection barrier requires 70 to 80 per cent of the population to be vaccinated, Tao Lina, a Shanghai-based vaccine expert, told the state-run Global Times.

Feng Duojia, president of the China Vaccine Industry Association, said time is an important factor for setting up an immune protection barrier.

If the vaccination campaign lasts too long and is outpaced by the virus' transmission speed, the immune barrier will be compromised, Feng said.

Wang appealed to more people to get vaccinated as soon as possible so that the protection barrier could arrive earlier, noting that vaccines are now the best option for an early return to normal life.

The continuous spread of the novel coronavirus will allow it to mutate quickly, he noted.

The best way to stop the virus from mutating faster is to cut its infection source, which means getting people vaccinated and building up an immunity against the virus.

About the concern of people that they would still get infected after receiving the vaccine, Wang said that the Phase III clinical trials showed that protection has occurred among the majority of the people, and the vaccine mainly protects people from severe illness or death.

In China, about one in a million people have adverse reactions or severe allergic reactions after vaccination, while the death rate from COVID-19 is two per cent," Wang said adding that vaccines will minimise the risk of infection.

According to John Hopkins coronavirus tracker, China has so far reported 102,091 cases and 4,843 deaths. Globally the contagion has infected 136,829,561 people and killed 2,948,943, it said.