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Should we expect new variants of Covid-19? The World Health Organization has classified two new daughter strains of Omicron, BA.4 and BA.5 as variants of interest. It is the South African team already at the origin of the discovery of Omicron which is behind their description.
It only took four months for the BA.4 and BA.5 strains to become the majority in the provinces ofSouth Africa where they were detected. They now represent between 60 and 75% of the cases sequenced there, a takeover that was made to the detriment of BA.2, which is still responsible for most of the cases of Covid-19 in the world.
Are these new strains therefore more effective? In any case, this is what the team that describes them for the first time believes, but it now remains to be seen why. Are these strains more contagious? Less sensitive to immune defenses? Or maybe the latter are less robust than expected following a recent contamination by BA.2? As often, only time will bring answers.
The F486 mutation observed in mink farms
A few elements, however, pushed theOMS to follow with interest these two new strains: a series of intriguing mutations and in particular the F486 mutation, already observed in mink farms hit by the epidemic. It is involved in an immune escape phenomenon.
However, the BA.4 and BA.5 variants are not yet classified as variants of concern by the WHO, but their spread will be monitored very closely.
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