WHO tracks two new sub-strains of Omicron

The World Health Organization (WHO) today added the BA.4 and BA.5 sublines, which are related to the BA.1 strain of the mutant Omicron, to the watchlist. Previously, WHO monitored BA.1 and BA.2 (currently dominant strains globally) along with BA.1.1 and BA.3.

“We made this move because additional mutations need to be studied further to determine their effect on immune evasion,” the WHO said.

The agency said that only a few dozen cases of infection with the BA.4 and BA.5 lines have been recorded in the GISAID system, a database that helps scientists in different countries consult and closely monitor the changes of the BA. nCoV.

The UK Health Security Agency said last week that the BA.4 subline was detected in South Africa, Denmark, Botswana, Scotland and the UK between January 10 and March 30. The majority of BA.5 infections were reported in South Africa as of late last week, while Botswana’s Ministry of Health today reported its first cases of BA.5, all aged 30-50, vaccinated. full dose of vaccine and mild symptoms.

Viruses frequently mutate as they spread and evolve, with some mutations affecting their ability to infect, avoid vaccines, and the immune system, as well as the severity of disease. The BA.2 subline of the Omicron strain currently accounts for 94% of the sequenced cases, but evidence suggests it causes less severe symptoms in humans compared with previous strains.

Last month, WHO health experts warned that even if Covid-19 cases were to drop to a lower level, the disease would still have the potential to cause thousands of deaths a year like other endemic diseases. have malaria and tuberculosis. The risk of the emergence of new strains is also unpredictable.

Worldwide, more than 499 million cases of nCoV have been recorded, of which more than 6.2 million people have died.

Vu Anh (According to Reuters)