BEIJING -- China's State Council joint prevention and control mechanism against COVID-19 has ordered the strict inspection of vaccine quality, safety and smooth cold-chain transportation, as well as timely and accurate delivery of vaccines, as the country's first self-developed vaccine got market approval with the vaccination campaign to be carried out nationwide gradually.

China has always attached great importance to the safety and effectiveness of COVID-19 vaccines. The mechanism has also emphasized the importance of providing medical support and service. It especially applies to timely treatment and reporting of adverse reactions during the vaccination drive.

The National Medical Products Administration also established a traceability information system for the management of approved vaccines.

China approved the emergency use of COVID-19 vaccines in June, targeting groups with high risks of infection. By the end of November, more than 1.5 million doses of Chinese COVID-19 vaccines had been distributed for emergency use, and 60,000 vaccinated people have traveled abroad to high-risk regions, with no severe adverse reactions reported.

On Dec 15, China officially launched a vaccination program for this winter-spring period targeting a number of 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 vaccines will be provided free of charge to all Chinese people.

The number of vaccination doses among the key groups has exceeded 3 million. "The 3 million vaccine doses, plus the previous 1.5 million doses, fully prove that Chinese vaccines are safe," said Zeng Yixin, deputy head of the National Health Commission.

The most common adverse reaction in the inoculation was pain at the injection site, with less than 0.1 percent cases of mild fever. About two cases per million encountered slightly serious adverse reactions such as anaphylaxis. All the reactions are controllable and have been well treated in a timely manner.

China granted conditional marketing authorization for the first COVID-19 vaccine in December. The inactivated vaccine developed by China National Biotec Group (CNBG) affiliated with Sinopharm showed 79.34 percent efficacy against COVID-19, according to the interim results of the phase-3 clinical trials.

Using killed pathogenic microorganisms to enhance the immunogenicity, inactivated vaccines have advantages of mature production process, controllable quality standards and wide protection range, according to Wang Junzhi, an academician with the Chinese Academy of Engineering.

China has laid a solid foundation for research into inactivated vaccines in recent years. Inactivated vaccines have been widely used to fight hepatitis A, influenza, hand-foot-and-mouth disease and poliomyelitis.

Authoritative studies show that Chinese-made inactivated vaccines can be more easily stored and delivered via the current cold-chain system, indicating greater accessibility without extra delivery cost, according to Foreign Ministry spokesperson Zhao Lijian.

Some other vaccines approved around the world have stricter cold chain requirements. For example, the COVID-19 vaccine developed by U.S. company Pfizer and German company BioNTech has to be stored at a temperature of minus 70 degrees Celcius.

China has adopted five technological approaches in developing COVID-19 vaccines, of which five are undergoing phase-3 clinical trials.

The five vaccines in phase-3 clinical trials include two inactivated vaccines developed by the CNBG, an inactivated vaccine developed by Sinovac Biotech, an adenovirus vector vaccine developed by the Academy of Military Sciences and CanSino Biologics Inc., and a recombinant sub-unit vaccine jointly developed by Anhui Zhifei Longcom Biopharmaceutical Co., Ltd. and the Institute of Microbiology under the Chinese Academy of Sciences.

Some countries, including the United Arab Emirates and Bahrain, have approved the Chinese inactivated vaccine registration according to the World Health Organization technical standards. Egypt licensed China's inactivated COVID-19 vaccine for emergency use on Saturday. Countries, including Brazil, Indonesia, Turkey, Chile and Malaysia, have ordered vaccines developed by Sinovac Biotech.

"China will vaccinate the eligible population as widely as possible, and gradually build an immune barrier in the whole population to control the epidemic," said Zeng. He added that 60 or even 70 percent of the vaccination rate is needed to establish universal protection.