File photo: CGTN

BEIJING, April 14 (Xinhua) -- China has approved three COVID-19 vaccine candidates for clinical trials, said an official with the Ministry of Science and Technology on Tuesday.

An adenovirus vector vaccine, developed by a research team led by Chen Wei with the Institute of Military Medicine under the Academy of Military Sciences, was the first to be approved to enter clinical trial.

The first phase of the clinical trial was completed at the end of March, and the second phase started on April 12.

It is the first COVID-19 vaccine in the world that has entered the second phase of clinical trial, according to the World Health Organization.