No recipient of the Chinese COVID-19 vaccine approved for emergency use has reported severe adverse effects, and no vaccine recipient who went to work in countries where the pandemic is still ongoing has been infected, an official said on Tuesday.

China is currently facing great pressure both from small cluster outbreaks domestically and from imported cases, Zhang Zhongwei, head of China's COVID-19 vaccine development task force, said in a news briefing by the Joint Prevention and Control Mechanism of the State Council.

As a result, it is a necessary measure to approve COVID-19 vaccines for emergency use for high-risk demographics, namely first-line medical personnel, border staff and people traveling overseas to work, as well as workers essential for a city's function, he said.

China's vaccine emergency use authorization progress is strictly governed by related laws and regulations, Zhang said, adding China has notified World Health Organization's representative in China and has garnered the organization's understanding and support.

Meanwhile, a dedicated approval committee headed by Zhong Nanshan, China's leading respiratory disease expert, along with other top experts in law, ethics and clinical medicine, is tasked of screening and selecting which vaccine gets approved for emergency use, Zhang said.

All vaccine recipients are administered voluntarily and are fully aware of the risks involved, Zhang said. In addition, there are mechanisms to closely monitor the recipients for any adverse effects should they occur, he added.