China-based Sinovac Biotech has announced that the Chilean Public Health Institute (Instituto de Salud Pública, ISP) has approved a phase II clinical trial for its inactivated Omicron strain COVID-19 vaccine and trivalent COVID-19 vaccine (ancestral, Delta and Omicron variants).

The clinical trial will evaluate the immunogenicity and safety of one booster dose of the two candidate vaccines in adults who had received two booster doses of CoronaVac, mRNA, or adenovirus vector COVID-19 vaccine. This study is the world's first study researching multivalent inactivated COVID-19 vaccine.

In this phase II randomized, double-blind, multicenter clinical trial, 826 fully vaccinated adults will be recruited. Participants belonging to the heterologous scheme are individuals who had received two CoronaVac doses, and two boosters of mRNA-based or viral vector-based vaccines, while participants of the homologous scheme had received four doses of CoronaVac. Individuals from the heterologous scheme will randomly receive a booster dose with the Omicron, Trivalent, or CoronaVac vaccines, while individuals from the homogeneous group will randomly receive a booster dose of the Omicron or the trivalent vaccines.