April 12, 2022
The World Health Organization is analyzing a few dozen cases of two new sub-variants of the Omicron strain to determine how infectious and dangerous they might be, according to Reuters.
The agency said it added BA.4 and BA.5 to its monitoring list because of their “additional mutations that need to be further studied to understand their impact on immune escape potential,” Reuters said.
All versions of Omicron have proven to be highly transmissible. The BA.2 subvariant now represents about 94% of all sequenced cases but does not appear to cause severe disease, Reuters said. Last week, the CDC said BA.2 accounted for three-quarters of all COVID cases in the United States.
So far only a few dozen cases of BA.4 and BA.5 have been detected. Last week, the UK’s Health Security Agency said BA.4 was detected in South Africa, Denmark, Botswana, Scotland, and England from Jan. 10 to March 30, Reuters said.
All BA.5 cases were in South Africa as of last week, Reuters said, but Botswana’s health ministry said Monday four cases of BA.4 and BA.5 had been detected among people aged 30 to 50 who were fully vaccinated and experiencing mild symptoms.
On Tuesday, Tulio de Oliviera, director of Centre for Epidemic Response and Innovation in South Africa, tweeted that BA.4 and BA.5 genomes had also been found in Belgium, Denmark, and Germany.
“Still no reason for alarm & it is good that Europe is also tracking variants & lineages,” he tweeted.