BEIJING -- One more Chinese adenovirus vector vaccine candidate against COVID-19 is ready for human trials at home and abroad, its developers said Monday.

Researchers from Tsinghua University, Tianjin Medical University and Kunming-based Walvax Biotechnology Co., Ltd. have started developing the vaccine since the outbreak of the epidemic. Compared with other candidates, it was produced using chimpanzee blood.

Because there is generally no pre-stored neutralizing antibody against chimpanzee adenovirus in the human body, the vaccine with this virus as the carrier will have the advantages of low adverse reactions, high production capacity and strong immunity after vaccination, said lead researcher Zhang Linqi, from Tsinghua University.

The vaccine makers have completed animal tests and started applying to launch human trials in China and overseas.

"No serious side effects have occurred in animals," said Zhang, adding that the results of the preclinical research support the safety of this vaccine and suggest the potential for further clinical tests.

Zhang noted that phase-3 clinical trials to verify the vaccine efficacy will be performed in pandemic areas abroad. "Like other Chinese COVID-19 vaccines, we are also facing the situation that there are not enough COVID-19 patients in China to participate in phase-3 trials."

An industrialization base of the patented chimpanzee adenovirus vector vaccine was launched Sunday in Beijing's Daxing District. Once the vaccine is proved effective after trials, it will be mass produced in the base.

The manufacturing plants are now under construction, and the vaccine is likely to hit market in mid-2021. The annual production capacity for the COVID-19 vaccine will top 200 million doses, according to a Walvax statement.

China currently has five vaccines entering phase-3 clinical trials including an adenovirus vector vaccine developed by the Academy of Military Sciences and CanSino Biologics Inc., said an official from the National Health Commission earlier in December.