Photo: CFP

Three inactivated vaccines against Omicron developed by major Chinese vaccine producers Sinopharm and Sinovac have been approved for clinical research in China's Hong Kong Special Administrative Region, the companies announced on Saturday. 

Two vaccines, developed by the Sinopharm's two institutes in Beijing and Wuhan, were approved by the University of Hong Kong and Hong Kong Hospital Authority as well as the city's drug authority, meaning that the city could officially conduct the sequential immunization clinical study of the two inactivated vaccines. 

Since the outbreak of the Omicron mutant strain, Sinopharm has been studying the research and development of a vaccine against the Omicron strain. Its affiliated Beijing Institute of Biological Products and Wuhan Institute of Biological Products made all-out efforts to carry out scientific research and developed the BIBP-novel coronavirus inactivated vaccine and WIBP-novel coronavirus inactivated vaccine, which were inoculated with the Omicron strain in Vero cells. 

After the vaccines were successfully developed, the company submitted ethical and clinical trial applications to the Hong Kong Research Center and obtained approval on April 12 and 13. 

The company said it will next conduct a random, double-blind and cohort study among people aged 18 and above who have completed the inoculation process to evaluate the safety and immunogenicity of the two vaccines. 

In a recent exclusive interview, chief scientist of Sinopharm's subsidiary China National Biotec Group Zhang Yuntao urged the elderly and those with chronic diseases to accept booster shots, as the move has proven effective in protecting them from severe cases and deaths in the face of Omicron. 

Zhang also revealed that the company's two Omicron-specific candidate vaccines were expected to enter clinical trials in the near future.

In the long run, Zhang said besides keeping developing candidates specifically for certain variants, vaccine manufacturers should also consider developing broad-spectrum vaccines that could be protective against various variants like Beta, Delta and Omicron.

Sinovac said in a statement it sent to the Global Times on Saturday that the company has been developing vaccines against the Gamma and Delta strains since 2021 and obtained the samples of patients infected with Omicron on December 5, 2021. The company then obtained samples of Omicron infections from the University of Hong Kong on December 9.

Results of preclinical studies showed that the inactivated Sinovac vaccine against Omicron variant was safe and effective in animals, the company said.

Sinovac has submitted clinical approval requests to several countries and regions since February with approval in Hong Kong representing the first green light for its inactivated vaccine against Omicron, it said.