WHO analyzes 2 new sub-variants of Omicron

The World Health Organization added BA.4 and BA.5, sister variants of variant Original BA.1 Omicron, on the watch list. Previously, WHO had tracked sub-variants BA.1 and BA.2 – which are the dominant strains globally – as well as BA.1.1 and BA.3.

WHO says it has begun monitoring new Omicron sub-variants BA.4 and BA.5 because “additional mutations need to be studied further to understand their impact on immune escape”.

Viruses always mutate, but only a few mutations affect their ability to spread or evade immunity created by vaccination or previous infection, or mutations can also affect how severe the disease is. important.

For example, BA.2 currently accounts for almost 94% of all cases COVID-19 have been sequenced and are more transmissible than other Omcron sub-variants. However, the evidence to date suggests that this variant is unlikely to cause severe disease.

According to WHO, only a few dozen infections with Omicron sub-variants BA.4 and BA.5 have been reported to the global GISAID database.

The UK’s Health Security Agency reported last week that BA.4 had been detected in South Africa, Denmark, Botswana, Scotland and the UK between 10 January and 30 March.

As of last week, all BA.5 sub-variant infections were reported in South Africa. As of April 11, the Botswana Ministry of Health announced that it had identified four cases of BA.4 and BA.5, all in fully vaccinated people aged 30 to 50 years and experiencing mild symptoms.