China Disease Control Expert: The place where the Omi Keron mutant was found is not necessarily the place of origin

(Fighting against New Coronary Pneumonia) China Disease Control Expert: The place where the Omi Keron mutant was found is not necessarily the place of origin

　　China News Service, Beijing, November 29. In response to the new coronavirus Omi Keron variant, the National Health Commission of China organized experts from the Chinese Center for Disease Control and Prevention to answer relevant questions. The full text of the relevant questions and answers was announced on the 29th.

CDC experts said that the Omi Keron mutant was first discovered and reported in South Africa, but it does not mean that the virus evolved and formed in South Africa. The place where the mutant was discovered is not necessarily the place of origin.

　　Regarding the discovery of the Omi Keron variant, experts said that on November 9, 2021, South Africa detected a new coronavirus B.1.1.529 variant from a case sample for the first time.

In just 2 weeks, the mutant strain became the absolute dominant mutant strain in the new crown infection cases in Gauteng Province, South Africa, and its growth was rapid.

On November 26, the World Health Organization defined it as the fifth "variant of concern" (VOC), named the Greek letter Omicron (Omicron) variant.

　　As of November 28, South Africa, Israel, Belgium, Italy, the United Kingdom, Austria, and Hong Kong, China, have monitored the input of this mutant strain.

Experts pointed out that other provinces and cities in China have not yet found the importation of this mutant strain.

The Omi Keron mutant was first discovered and reported in South Africa, but it does not mean that the virus evolved in South Africa. The place where the mutant was found is not necessarily the place of origin.

　　Experts said that according to the information currently shared by the new crown virus database GISAID, the number of mutation sites of the new crown virus Omi Keron mutant strain is significantly more than that of all the new crown virus mutant strains that have been circulating in the past two years, especially in the virus spike protein mutations. .

　　Experts pointed out that at present, there is no systematic research data on the transmission, pathogenicity and immune escape ability of Omi Keron variants in the world.

However, the Omi Keron variant also has important amino acid mutation sites in the first four VOC variants Alpha, Beta, Gamma and Delta spike proteins, including enhanced cell receptors. Mutation sites for somatic affinity and virus replication ability.

Epidemiological and laboratory surveillance data show that the number of cases of Omi Keron mutants in South Africa has increased sharply and partially replaced the delta mutants. The transmission capacity needs to be further monitored and studied.

　　Talking about the impact of Omi Keron mutant strains on vaccines and antibody drugs, experts said that studies have shown that if the new coronavirus S protein has K417N, E484A or N501Y mutations, it indicates that the immune escape ability is enhanced; while Omi Keron mutant strains exist at the same time "K417N+E484A+N501Y" triple mutation; in addition, the Omi Keron variant also has many other mutations that may reduce the neutralizing activity of some monoclonal antibodies.

The superposition of mutations may reduce the protective efficacy of some antibody drugs against Omi Keron mutants, and the ability of existing vaccines to escape immunity needs further monitoring and research.

　　Regarding whether the Omi Keron variant has an effect on the nucleic acid detection reagents currently used in China, experts also pointed out that the genome analysis of the Omi Keron variant shows that its mutation site does not affect the sensitivity and sensitivity of the mainstream nucleic acid detection reagents in China. Specificity.

The mutation sites of the Omi Keron mutant strain are mainly concentrated in the highly variable region of the S protein gene, and are not located in the nucleic acid detection reagent primers and probe target regions published in the eighth edition of China's "New Coronavirus Pneumonia Prevention and Control Program".

　　Experts also mentioned that data from multiple laboratories in South Africa suggests that nucleic acid detection reagents that detect the S gene may not be able to effectively detect the S gene of the Omi Keron variant.

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