BEIJING -- "It took only 15 minutes from registration to getting the shot," said Mr. Li, a resident of Dongcheng District in Beijing.

Mr. Li had just got his first shot of COVID-19 vaccine. Since the Spring Festival, vaccination programs have been rolled out to residents across the Chinese capital, after key groups such as workers handling imported cold-chain products completed the two-dose vaccination.

In Daxing District in southern Beijing, where sporadic cases were reported last month, more than 310,000 residents had received the vaccine as of Saturday.

China follows a vaccination strategy that is different from that of many other countries. According to the National Health Commission (NHC), China aims to vaccinate the eligible population as widely as possible and gradually build an immune barrier within the whole population to control the epidemic.

The vaccination is being administered first to key groups, then to high-risk groups and then the general population, as the vaccine's production capacity increases.

The limited initial supply of COVID-19 vaccines raises the question of how to prioritize available doses. In a study published in the journal Science last month, U.S. researchers found that the infection was minimized when vaccines were prioritized to adults aged 20 to 49, but mortality was the lowest when the vaccine was prioritized to people over 60 years old.

Experts have pointed out that the vaccination strategy should consider epidemic situations and control goals.

Shao Yiming, chief expert at the Chinese Center for Disease Control and Prevention (CDC), said that China's vaccination strategy is scientifically sound considering the epidemic situation in the country.

In December, China officially launched a vaccination program for this winter-spring period targeting several key groups, including those engaged in handling imported cold-chain products, customs officers, medical workers, and people working in public transport and fresh markets.

The COVID-19 outbreaks in China over the past few months were related to key groups that represent no more than 20 percent of the country's population, said Zhang Hongtao from the University of Pennsylvania.

He noted that it is far better to get herd immunity in key groups in the first instance than to vaccinate the same number of people in the general population.

As of Feb. 9, China had administered 40.52 million COVID-19 vaccine doses to key groups, said NHC spokesperson Mi Feng at a press conference.

Some reports recently warned of a potential immunity gap between China and other countries, given the limited number of infections in China.

Feng Duojia, president of the China Association for Vaccines, said such a gap will not occur because China is promoting mass vaccination along with the global vaccination plan, and it may adjust the vaccination plan and strategy in accordance with the development of the epidemic.

China has a good tradition of overcoming epidemics through vaccination and building an immune barrier for all people, noted Feng. Through vaccination, smallpox was eradicated, polio eliminated, hepatitis B significantly reduced and measles controlled.

It is understandable that some people may have questions and hesitations about COVID-19 vaccines in the beginning, but Chinese people have a high degree of awareness of public participation in solving health issues, and the public's willingness to vaccinate will certainly become stronger and stronger with the popularization of vaccine science, Feng said.

This has been proved by the smooth progress of the current vaccination program, he said.

Last month, Ning Yi, a professor from the School of Public Health of Peking University, said at a seminar that he saw no problem with the vaccination rate reaching above the level for herd immunity in China.

Ning pointed out that the world should care more about underdeveloped countries. The future epidemic-control challenge is mainly related to imported cases from countries that cannot get enough vaccines.

Last week, China delivered batches of domestically-developed COVID-19 vaccines to several developing countries, including Mexico, Belarus, Senegal and Colombia.

Chinese vaccines have become a reliable source for many developing countries to fight the COVID-19 pandemic. China's expanding efforts to promote the fair and equitable distribution of vaccines, especially in developing countries, have shown that China is fulfilling its commitments to make China's vaccines a global public good.

According to the Foreign Ministry, China has provided vaccine assistance to 53 developing countries that have made requests, and has exported vaccines to 22 countries. China also decided to provide 10 million doses of domestic vaccine to the COVAX initiative to meet the urgent needs of developing countries.

At least eight foreign heads of state or government have received Chinese vaccines and many countries have sent charter planes to China to transport vaccines, which is their vote of confidence in the safety and effectiveness of Chinese vaccines, said Hua Chunying, a Foreign Ministry spokesperson.

As vaccines are the ultimate solution to win the final victory over the virus, China has started early and made arduous efforts in developing COVID-19 vaccines, adopting multiple technological approaches and pooling national resources to fast-track the process.

China has granted conditional market approval to two domestically-developed vaccines. It now has 16 COVID-19 vaccines undergoing clinical trials, six of which have entered phase-3 clinical trials.

Chinese vaccine producers are also ramping up the production of vaccines to ensure global supply. Yin Weidong, chairman and CEO of Sinovac said the company has constructed a second production line, which will increase its annual production capacity to 1 billion doses. It will also export semi-finished jabs to some countries, and help build local filling and packaging lines in importing countries to improve production capacity and efficiency.

Whether the world can be reopened depends on whether the access to vaccines around the world follows the principle of fairness, said Zhang Wenhong, head of the Center for Infectious Diseases with the Shanghai-based Huashan Hospital and head of Shanghai's COVID-19 clinical expert team.

"Global collaboration is the common option for all countries in the world," said Zhang.