WHO confirms the presence of a subvariant of Omicron in 57 countries

Since it was first detected in Southern Africa ten weeks ago, Omicron has continued to spread and with it its sub-variants. One of them has even been detected in 57 countries, the World Health Organization announced on Tuesday.

In its weekly epidemiological bulletin, the WHO explains that the Omicron variant, which accounts for more than 93% of all coronavirus specimens collected over the past month, has several subvariants: BA.1, BA.1.1, BA. 2 and BA.3. The first two still constitute over 96% of the Omicron sequences uploaded to the global GISAID database.

But there is a marked increase in the number of cases involving BA.2, which has several different mutations from the original version, in particular on the spike protein marking the surface of the virus and which is essential for entering human cells. “Sequences designated BA.2 have been submitted to GISAID by 57 countries to date,” the WHO points out, adding that in some countries this subvariant now accounts for more than half of the Omicron sequences collected.

Further studies

The Organization further points out that scientists still know little about the differences between the subvariants. She therefore requested that studies be carried out on the characteristics of the virus, in particular on its transmissibility, its ability to escape immune protection and its virulence.

Several recent studies have already suggested that BA.2 is more contagious than the original Omicron. Maria Van Kerkhove, one of the WHO’s leading experts on Covid-19, for her part clarified on Tuesday that information on the subvariant was limited, but that some initial data indicated that BA.2 had “a slight increase in growth rate compared to BA.1”. Omicron generally causes less severe illnesses than previous variants of the coronavirus and according to Maria Van Kerkhove there is no evidence so far that the BA.2 sub-variant is more severe.