Two Chinese inactivated vaccines, including a trivalent one and a monovalent one against Omicron variants of the COVID-19 virus, have received approval for clinical research in Chile, vaccine developer Sinovac announced.

The trivalent vaccine targets the Delta and Omicron variants alongside the original strain of COVID-19, according to the Chinese biopharmaceutical company.

Preclinical studies have shown that the two vaccines are safe and effective.

In the forthcoming clinical research, a multicenter, randomized, double-blind and positive-controlled method will be adopted to study the immunogenicity of the two vaccines among adults aged over 18 who have received four doses of COVID-19 vaccines.

The research will have 826 participants who will be divided into two groups. The heterologous group will comprise people who have received two doses of CoronaVac developed by the company followed by two doses of mRNA or adenovirus vector vaccines as a booster shot, while the homologous group will include those who received four doses of CoronaVac, the company said.

In the heterologous group, 576 participants will be vaccinated with a dose of the trivalent vaccine, or the Omicron vaccine, or CoronaVac, and other people in the second group will receive a dose of the trivalent vaccine or the Omicron vaccine.

The research will also assess the capacity of antibodies induced by the trivalent vaccine to neutralize various strains, the company said.

The vaccine against Omicron variants has entered clinical trials in the Chinese mainland and Hong Kong Special Administrative Region, and its immunogenicity and safety data is expected this month, the company added. 

(With input from Xinhua)