CanSino Biologics Inc., China's adenovirus-based single-dose COVID-19 vaccine producer, launched phase-I and -II clinical trials for its messenger Ribonucleic acid (mRNA) COVID-19 vaccines on Thursday, according to the trial-tracking website under the National Medical Product Administration.

The randomized, double-blind and placebo-controlled trials are carried out at three centers in different provinces across China in order to evaluate the efficacy, safety and immunogenicity of the company's COVID-19 mRNA vaccine in adults 18 years old and above.

The trials will also compare vaccines at low and high doses and different age groups. 

China had administered nearly 3.35 billion doses of COVID-19 vaccines on the Chinese mainland as of Wednesday, according to the latest data from the National Health Commission. Most are inoculated with traditional inactivated vaccines, while the adenovirus-based and recombinant protein COVID-19 vaccines are encouraged as boosters. 

Meanwhile, there are several homegrown mRNA vaccine candidates pushing its vaccine development for the market as an alternative option. Both CanSino and CSPC Pharmaceutical were approved by the National Medical Products Administration of China to conduct clinical trials last month.

The only mRNA vaccine candidate in China being tested in large scale phase-III clinical trials is the two-dose ARCoV from the Academy of Military Medical Sciences, Suzhou Abogen Biosciences and Walvax Biotechnology.