South African scientists have discovered two new sublineages of the Omicron coronavirus variant, said Professor Tulio de Oliveira, who runs gene-sequencing institutions in the country.
The lineages have been named BA.4 and BA.5, he said by text message and in a series of postings on Twitter.
Still, Prof de Oliveira said, the lineages have not caused a spike in infections in South Africa and have been found in samples from a number of countries.
"Given the very low infections, hospitalisations and deaths in South Africa, we are alerted about the continued evolution but not concerned," Prof de Oliveira said.
"All of the laboratory science on virus neutralisation and vaccines is already under way and we are strengthening genomic surveillance."
South Africa and Botswana were the first to discover Omicron in November last year and South Africa was the first country to be hit by a wave of infections caused by the strain. Hospitalisations and deaths were a fraction of those caused by the Delta variant even as daily cases hit a record in December. The sublineages have also been found in samples from Botswana, Belgium, Germany, Denmark and Britain, Prof de Oliveira said on Twitter.
The two lineages have similar mutations on their spike proteins, the part of the virus that helps the virus attach to human cells, to the BA.2 sublineage, which appears to be more infectious than the original Omicron strain. They also have some additional mutations, he said.
The two sublineages differ from each other in terms of amino acid mutations outside the spike protein, he said. Botswana has also announced the discovery of the variants.
South Africa on Monday (April 11) reported 553 new coronavirus cases, with 5 per cent of tests coming back positive.
