Asian Tech Press (Dec 13) -- Chinese vaccine maker Chongqing Zhifei Biological Products Co., Ltd. (Zhifei), its research unit said Monday that its recombinant COVID-19 vaccine remains effective against the Omicron variant.

The vaccine, developed by the Institute of Microbiology, Chinese Academy of Sciences (IMCAS) and Zhifei's subsidiary Anhui Zhifei Longcom Biopharmaceutical, was approved for emergency use in China on March 10, 2021.

The study, organized by the IMCAS, tested blood serum from subjects who had been administered a three-dose course of Zhifei vaccine for 1 month, by means of a pseudovirus cross-neutralization assay.

The results showed that 78% (25/32) of the subjects' serum tested positive for neutralizing antibodies against the Omicron variant. Among them, 100% (16/16) of the serum from subjects who had been vaccinated for more than 4 months between the second and third doses was positive for neutralizing antibodies against the Omicron variant.