China launched a clinical trial for an inactivated vaccine against Omicron variants in Hangzhou, east China's Zhejiang Province on Sunday.

China National Biotec Group, a subsidiary of Sinopharm, developed the vaccine that has been undergoing research and testing since December 2021, the company said.

In the clinical trial, a randomized, double-blind and cohort study will be carried out among people aged 18 and older who have been inoculated with two doses to evaluate the safety and immunogenicity of the inactivated vaccine.

The  clinical trial candidates are whose who have not received any COVID-19 vaccine or infected by the virus.

"People who are vaccinated might have already developed antibodies," Li Lanjuan, director of China's State Key Laboratory for Diagnosis and Treatment of Infections, said at the launch.

"We need to test the effectiveness of the vaccine through the level of the immunogenicity and antibodies the candidates generate."

The expert said the next step is to test the vaccine's efficacy on vaccinated candidates.

The National Medical Products Administration approved the vaccine for clinical trials on April 26.