Russian health watchdog detects more contagious Omicron subvariant in Russia

Russian health authorities have confirmed that a more contagious sub-variant of the Covid-19 Omicron strain, called BA.4, has started to spread in the country.

Kamil Khafizov, who heads genome research at the Central Research Institute of Epidemiology in Rospotrebnadzor, said on Sunday that two national laboratories had submitted the viral genome of the BA.4 sublineage to the Virus Genome Aggregator database. of Russia (VGARus).

“In the VGARus database, developed by the Central Research Institute for Epidemiology of Rospotrebnadzor, the genome of the SARS-CoV-2 virus, which belongs to the omicron BA.4 subvariant, was deposited”, Khafizov said. “One sample was deposited by the Smorodintsev Influenza Research Institute, and another – by the Central Scientific Research Institute for Epidemiology in Rospotrebnadzor.”

As of the last update, BA.2, commonly referred to as stealth variant with an estimated 10% growth advantage over BA.1, accounts for 95% of Covid cases in Russia. Still, the BA.4 sub-variant of Omicron is believed to have surpassed BA.2 in terms of transmissibility.

Khafizov believes that good herd immunity, acquired through vaccination and previous waves of the new coronavirus, will prevent the country from experiencing a sharp increase in new cases of omicron subvariants.

“However, a number of recently published research shows that the BA.4 and BA.5 sublines of the omicron are slightly more transmissive than earlier versions of the omicron,” the scientist added.

Omicron’s BA.4 sub-variant began spreading in South Africa in April. The new virus strain shares similar mutations on its spike proteins, the part of the virus that helps the virus attach to human cells, like the original Omicron variant. However, the BA.4 subvariant has more in common with the BA.2 variant, which appears to be more infectious than the original Omicron strain. BA.4 also has a number of additional mutations, some of which could alter their characteristics.

BA.4 is often discussed with BA.5 because the mutations in their spike protein gene are identical, even though they differ in mutations found elsewhere.

Studies have shown that both of these strains are highly infectious, able to evade the immune system and can lead to community spread. According to the Global Vaccine Alliance Gavi, the two new variants carry an L452R mutation, which was also previously detected in the Delta variant, making the virus more contagious by enhancing its ability to attach to human cells, as well as helping it partially escape destruction by immune cells. BA.4 and BA.5 also possess a genetic change, called the F486V mutation, near where their spike protein binds to human cells, which may also help them partially evade people’s immune responses.

The World Health Organization (WHO) has called for close monitoring of the BA.4 and BA.5 Omicron subvariants as they are spreading rapidly around the world. According to WHO data released on June 8, BA.4 and BA.5 cases have been detected in more than 40 countries, and the number of cases and affected countries continues to rise.