Antibody response from China Zhifei's COVID shot weaker against Omicron

[December 13, 2021]  BEIJING (Reuters) - China's Anhui Zhifei Longcom Biopharmaceutical said on Monday a small laboratory test showed its COVID-19 vaccine could trigger antibodies against the Omicron variant though the response was weaker than against an older variant of the virus.

The unit of Chongqing Zhifei Biological Products is the first Chinese vaccine developer to announce early data on how its COVID-19 vaccine work against Omicron, which has triggered global alarm about another surge in infections.

Cases of Omicron have already been reported in 57 nations.

Zhifei Longcom said neutralising antibodies against Omicron were detected in samples from 78% of 32 subjects who had completed a three-shot inoculation course a month earlier.

Among the 32 subjects, 16 received their second and third doses more than four months apart, and all of them had neutralising antibodies to Omicron. But the level of antibodies showed an approximate three-fold drop compared with that seen against the original coronavirus.

The firm did not provide further details in the readings, and the shot's protection rate against Omicron-caused infection, severe disease or death remained unclear.

The shot has been approved in China, Indonesia and Uzbekistan.

Zhifei Longcom also said on Monday a Phase III clinical trial showed its vaccine had a 81.43% efficacy against COVID-19 of any severity, slightly lower than the 81.76% rate that its parent company Chongqing Zhifei Biological Products announced in August.

(Reporting by Roxanne Liu and Ryan Woo)

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