China had administered nearly 82.85 million doses of COVID-19 vaccine as of Tuesday as it prepares a campaign to vaccinate its entire population, the State Council's Joint Prevention and Control Mechanism said on Wednesday.

More than 100 million doses of domestically made vaccine have been delivered in China and overseas, and they have proved safe and effective, it added.

So far, four vaccines have been approved for public use in China, and one vaccine candidate has been OK'd for emergency use.

"We must attach great importance to the vaccination work and continue to ramp up vaccination efforts," National Health Commission Minister Ma Xiaowei said on Wednesday.

Ma said more inoculation centers should be set up at hospitals in counties or larger jurisdictions, and temporary or mobile vaccination sites should be established at high-density population areas and workplaces, including schools, factories and construction sites.

Local authorities should devise precise and flexible distribution plans and secure cold-chain logistics for transporting these products, he added.

In Beijing, a robust inoculation system has taken shape that can administer more than 300,000 doses every day. It depends primarily on large and medium-sized vaccination sites, but also includes smaller sites and door-to-door vaccination service.

China is implementing a three-step approach for its mass immunization program－first inoculating groups at highest risk of contracting the disease, then moving to vaccinate the elderly and people with chronic diseases, and finally serving all other people who want to be vaccinated.

As the program gathers speed nationwide, the current focus is to expand the vaccination of people working in healthcare, transportation, education and other key industries, as well as those employed in large markets, companies and office buildings, according to the State Council's Joint Prevention and Control Mechanism.

Meanwhile, people living near borders and key ports and those working in labor-intensive industries will also be prioritized, it said.

Ma stressed expanding monitoring for adverse reactions and follow-up visits to vaccinated groups as well as paying close attention to people who have delayed adverse reactions and ensuring swift treatment for them.

In China, all vaccination sites now have ambulances, first-aid personnel and medications. Each site has prepared an emergency means of transferring potential COVID-19 patients.

"We must ensure the safety of inoculation services and boost their accessibility and convenience," Ma said.

As researchers collect data on contraindications for use of COVID-19 vaccines, authorities say the next step is to provide a standard and detailed list of people who are advised against being inoculated.

Zhang Wenhong, leader of the Shanghai expert team for treating COVID-19 patients, said based on mathematical models, at least 70 percent of the population must be fully inoculated to achieve herd immunity to the disease.

"However, because the efficacy rate of vaccines is not 100 percent, the vaccination rate should increase to 80 percent, and the higher, the better," he said on Wednesday during an online meeting.

Xinhua contributed to this story.