Gao Qiang, general manager of Chinese vaccine maker Sinovac Biotech, said the company has established a robust adverse effect monitoring system in accordance with global guidelines with all its foreign partners, including in Brazil, Indonesia and Turkey.

"We have not received a single report of vaccine-related severe adverse effects from our partners," he said.

Domestically, China has a world-class adverse effect surveillance system that is certified by the WHO for vaccines on the market, according to the Chinese Center for Disease Control and Prevention. This system has played a key role in tracking and investigating vaccine-related adverse effect incidents over the past decade, it added.

Zhao Xing, a Foreign Ministry official, said China is proactively fulfilling its promise of making COVID-19 vaccines a global public good and promoting equitable access to safe and effective vaccines, especially for developing countries.

On Oct 8, China joined COVAX, an initiative co-led by the WHO and partners to ensure efficient and equitable global access to a COVID-19 vaccine. As of Tuesday, 184 countries and regions have joined the initiative.

"Our vaccine development is leading the world, and we have enough production capacity, but we still want to join COVAX because we want to promote equal and fair access to the vaccine under the initiative," Zhao said.

"By joining the initiative, hopefully we can encourage more countries to participate in the project as well," he said, adding that China will enhance international collaboration to contribute to global public health and safeguard the well-being of people around the world.