BEIJING (Reuters) – Two candidate COVID-19 vaccines developed by units of the China National Biotec Group (CNBG) to target the Omicron variant have been approved for clinical trials as boosters in Hong Kong, the Sinopharm subsidiary said on Saturday. .

Scientists around the world are racing to study improved injections against Omicron, as data indicate that antibodies produced by vaccines based on older strains show lower activity in neutralizing the highly transmissible variant.

The two candidates, both containing inactivated or “killed” Omicron virus and similar to the two Sinopharm vaccines used in China, will be tested on adults who have already received two or three doses of the vaccine, CNBG said in a statement.

He did not specify which vaccine products trial participants would have received before taking the experimental booster, or how many subjects would be recruited.

A Chinese study https://www.medrxiv.org/content/10.1101/2022.02.19.22271215v1.full.pdf showed that a fourth dose of BBIBP-CorV, an existing Sinopharm vaccine, did not significantly increase the antibody levels against Omicron when given six months after a third booster dose on a regular two-dose schedule.

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While the fourth dose restored antibody levels to around the peak levels that followed the third dose, the researchers said new vaccines would offer a better alternative as future boosters.

(Reporting by Roxanne Liu and Andrew Galbraith; Editing by Edmund Klamann)

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