China is working around the clock to build COVID-19 herd immunity through its orderly and smooth rollout of vaccines, with 64.98 million doses administered as of last week, officials said on Monday.

They said the country's coordinated national inoculation networks, robust production and logistics operations, and a stringent supervision system will underpin the ongoing mass immunization program, while ensuring the quality and safety of China's homegrown vaccines.

"The best method to prevent coronavirus infections is to get vaccinated. Through vaccination, individuals can protect themselves and a wider population can also mount protection against the virus," Li Bin, vice-minister of the National Health Commission, said during a news conference.

Li added that even though the epidemic situation in China has remained stable, thanks to effective disease control measures, the risk of imported cases and infection clusters cannot be ruled out, and the majority of the population is still susceptible to the virus.

The country's mass vaccination program is currently targeting key groups, including workers at higher risk of infection, essential personnel, and people working in border regions and labor-intensive industries, Li said, adding that seniors who are in good condition and need to be vaccinated for special reasons also are in this group.

The second phase will focus on people who are more likely to develop severe infections, including the elderly and those with chronic diseases. "Due to limited clinical trial data on this group, we will arrange for them to get vaccines in accordance with research results," Li said.

The third and final phase will cover those in the remaining population who are willing to be inoculated, he said.

Wang Huaqing, chief expert for the immunization plan at the Chinese Center for Disease Control and Prevention, said the global death rate for COVID-19 is estimated to be about 2 percent.

"The rate is high and the key to reining in the virus is vaccination. We hope one day we can establish herd immunity through vaccination. … Enabling all people eligible for vaccination to receive doses is the basis," he said.

China has so far approved four domestically developed vaccines for public use.

Tian Yulong, a senior official at the Ministry of Industry and Information Technology, said all four vaccine developers are scaling up their manufacturing capacity while strictly abiding by safety protocols.

Tian said that in order to ensure stable supplies of ingredients used to make vaccines and smooth out distribution and transportation of finished products, the ministry has also established a highly efficient cooperation mechanism with other departments and prioritized allocation of key ingredients to vaccine producers.

"With the expanding production capacity, we will increase domestic vaccine supplies and supplies dispatched overseas simultaneously, and continue to cooperate with other countries to fight the disease," he said.

As of the end of February, China had provided vaccine aid to 53 countries and exported vaccines to 27 countries, according to the Foreign Ministry.

Quality supervision

Yuan Lin, an official at the National Medical Products Administration, said China's supervision and management system of vaccine quality has been globally recognized.

He said drug regulators on different levels have launched regular inspections and spot checks at factories producing COVID-19 vaccines.

The administration is also working closely with relevant government departments to keep track of vaccines, watch for any cases of adverse effects and severely punish any violators, he added.

Wang Junzhi, an academician at the Chinese Academy of Engineering, said no known variants of the novel coronavirus have been found to weaken the effectiveness of the four Chinese vaccines approved for use.