More than 9 million doses of COVID-19 vaccines have been administered across China, and the safety and efficacy of the vaccines have been proved, a top health official said.

With production increasing, the number of vaccine doses will be extended to cover the whole Chinese population free of charge as a crucial weapon for epidemic prevention and control, Vice-Health Minister Zeng Yixin said over the weekend.

Nearly 7.5 million doses of COVID-19 vaccines have been given since Dec 15, when China started a large-scale vaccination campaign targeting key groups such as front-line workers handling imported cold-chain food, as well as public transport and health workers, Zeng said at a news conference at the State Council Information Office on Saturday.

Another 1.6 million doses had already been administered by that date to people nationwide who are at higher risk of contracting the disease, he said.

Wang Huaqing, chief expert for the immunization plan at the Chinese Center for Disease Control and Prevention, said data collected over the use of the vaccines have shown that they are safe, with the chances of experiencing serious side effects standing at about one for every 1 million doses.

Local governments across the nation have been ordered to provide COVID-19 vaccinations for free during the campaign, Zeng said.

Li Tao, deputy head of the National Healthcare Security Administration, said the public will get free COVID-19 vaccinations on a voluntary basis when the mass vaccinations start. The expenses for the vaccination will be borne by the basic medical insurance fund and government, she said.

"Providing COVID-19 vaccinations to the public free of charge will help establish an immunization barrier quickly to maintain healthy economic and social development," Li said.

China granted conditional market approval for its first COVID-19 vaccine on Dec 30, but vaccines in the last stage of clinical trials have been available for emergency use in the country since June. By the end of December, 14 COVID-19 vaccines developed by China were under clinical trials, including five in phase 3, the final trial before a vaccine is approved for market.

The inactivated COVID-19 vaccine, developed by State-owned Sinopharm, which won conditional market approval, is safe and has an efficacy of 79 percent, the company said. It had already gained approval for general use in the United Arab Emirates and Bahrain before winning conditional market approval from China's top drug regulator.

Zeng said that based on the latest research, the efficacy of COVID-19 vaccines in China will not be affected by the new variant of the virus discovered in the United Kingdom.