HEFEI, Nov. 20 (Xinhua) -- Chinese vaccine maker Anhui Zhifei Longcom Biopharmaceutical Co., Ltd. has commenced phase-3 clinical trials for its COVID-19 vaccine, planning to recruit 29,000 volunteers across the world.

This is China's first phase-3 efficacy study for a recombinant subunit COVID-19 vaccine candidate, the company said in a statement on Thursday.

Jointly developed by the company and the Institute of Microbiology under the Chinese Academy of Sciences, the vaccine was issued with a clinical research permit from the National Medical Products Administration on June 19.

Researchers started phase-1 and phase-2 clinical trials on June 23, which were randomized, double-blind and placebo-controlled. Volunteers, aged between 18 and 59 from Beijing, Chongqing and Hunan, received the vaccine to determine whether it is safe for use on humans.

The results of the early-stage trials support the safety and immunogenicity of this vaccine, suggesting the potential for further clinical tests. The Chinese drug regulator granted the developers permission to conduct global multi-center research on Nov. 4.

The company said the research, which plans to enroll up to 29,000 adults aged 18 and up, was launched on Wednesday in Xiangtan County, central China's Hunan Province. Global trials are expected to begin in Uzbekistan late this month, followed by trials in Indonesia, Pakistan and Ecuador.

A COVID-19 vaccine manufacturing plant of the company was put into use in September. The annual production capacity for the COVID-19 vaccine will top 300 million doses, according to the company.

A Chinese Foreign Ministry spokesperson said Wednesday that China had five COVID-19 vaccine candidates undergoing phase-3 trials in the United Arab Emirates, Brazil, Pakistan and Peru.