MOSCOW, December 5. /TASS/. Antibodies, which are developed after the infection with delta strain of the coronavirus, may not protect from the new omicron strain and vice versa, Director General of the DNKOM Center for Molecular Genetic Studies Andrei Isayev told TASS.

"Big number of mutations means that the virion of this strain structurally differs from virions of other strains - they have different spike proteins. That is why the antibodies developed by those who earlier had suffered from other strains or got vaccinated cannot brace omicron. That means that there will be no cross-immunity between the omicron and other strains. Accordingly, antibodies that are developed after infection with omicron will not protect against delta - and vice versa. So, COVID-19 can split into two populations: Covid-D and Covid-O, as one evolutionary biologist correctly wrote," he said.

Isaev also noted that due to the large number of mutations in the omicron, it is difficult to predict how it will behave in the future.

"The phenomenon is absolutely new," the expert said.

On November 26, a new variant of the coronavirus was identified in South Africa. The World Health Organization (WHO) designated the B.1.1.529 variant as a "Variant of Concern" and assigned it the Greek letter Omicron. In its statement, the WHO noted that "this variant has a large number of mutations, some of which are concerning." Several changes at once in the spike protein can potentially hinder the neutralization of the pathogen by antibodies which may impact the effectiveness of vaccines.