JOHANNESBURG: Scientists in South Africa said Thursday they had detected a new Covid-19 variant with multiple mutations, blaming it for a surge in infection numbers.

"Unfortunately we have detected a new variant which is a reason for concern in South Africa," virologist Tulio de Oliveira told a hastily-called news conference.

The variant, which goes by the scientific lineage number B.1.1.529, "has a very high number of mutations," he said.

"It's unfortunately causing a resurgence of infections," he said.

It has also been detected in Botswana and Hong Kong among travellers from South Africa, he said.

Health Minister Joe Phaahla said the variant was of "serious concern" and behind an "exponential" increase in reported cases, making it "a major threat".

Daily infections shot to more than 1,200 on Wednesday, up from around 100 earlier this month.

Before the detection of the new variant, authorities had predicted a fourth wave to hit South Africa starting around the middle of December, buoyed by travel ahead of the festive season.

The government-run National Institute for Communicable Diseases (NICD) said 22 positive cases of the B.1.1.529 variant have been recorded in the country following genomic sequencing.

It said in a statement Thursday that detected cases and the percentage testing positive are "increasing quickly" in three of the country's provinces including Gauteng, which includes Johannesburg and Pretoria.

A cluster outbreak was recently identified, concentrated at a higher education institute in the capital Pretoria, the NICD said.

Covid-19 toll tops 1.5 million in Europe: AFP tally

Last year South Africa also detected the Beta variant of the virus, although until now its infection numbers have been driven by the Delta variant, which was originally detected in India.

The country has the highest pandemic numbers in Africa with around 2.95 million cases, of which 89,657 have been fatal.

Ten mutations

Scientists said the new B.1.1.529 variant has at least 10 mutations, compared to two for Delta or three for Beta.

"What gives us some concerns (is) that this variant might have not just have enhanced transmissibility, so spread more efficiently, but might also be able to get around parts of the immune system and the protection we have in our immune system," said researcher Richard Lessells.

So far the variant has been seen spreading especially among young people.

Coronavirus toll at 1100 GMT Thursday

But the coming days and weeks will be key to determine the severity of the variant, Lessells said.

Neutralising the variant is "complicated by the number of mutations this variant" contains, said one of the scientists Penny Moore.

"This variant contains many mutations that we are not familiar with," she added.

After a rather slow start to South Africa's vaccination campaign, around 41 percent of adults have received at least a single dose, while 35 percent are fully vaccinated.