Germany and Switzerland have banned travel from South Africa after Africa’s most industrial nation warned of the emergence of a new coronavirus variant.

This new variant — which shares some characteristics to the new strain that has appeared in the UK but is different — has been present in about nine in 10 new recorded cases in South Africa in recent weeks.

This “strongly suggests that the current second wave we are experiencing is being driven by this new variant,” said Zweli Mkhize, South Africa’s health minister. The German and Swiss governments barred incoming flights from South Africa from the start of Monday.

The flight ban “aims to prevent the spread of this new variant of the virus” which “according to initial findings, is significantly more contagious than the known form,” the Swiss federal office of civil aviation said in a statement late on Sunday.

Scientists have yet to determine how the South African variant could be driving more infections, but as with the UK variant do not believe that it is innately more severe.

“It is still very early but at this stage, the preliminary data suggests that the virus that is now dominating in the second wave is spreading faster than the first wave. It is not clear if the second wave has more or less deaths, in other words, the severity is still very unclear,” said Salim Abdool Karim, an epidemiologist advising South Africa’s government.

Genome data specialists have traced the South African variant’s lineage to Nelson Mandela Bay in the Eastern Cape, the first major metropolitan area to be hit by the country’s second wave.

South Africa has been recording about 10,000 cases a day in recent days, the highest incidence of cases since the crest of its first wave in August.

In the worst hotspots — which include the Eastern Cape and Western Cape — about one in three tests for the virus have been coming back positive, an indication that it is spreading rapidly.

The UK and South African variants have emerged independently from each other but they share a crucial mutation of the spike protein that the coronavirus uses to gain entry to human cells.

Scientists in South Africa have said it is “very plausible” that this spike mutation, known as N501Y, may lead to higher rates of infection based on a possible stronger viral load. But they have cautioned that more study is needed. “Overall there is some evidence that this new variant might be being transmitted more readily than other variants, although the mechanism of this remains to be fully worked out,” said South Africa’s department of health.

President Cyril Ramaphosa has imposed tighter national restrictions in recent days including a longer night-time curfew and a ban on weekend alcohol sales in order to control so-called “superspreader” events such as festive summer parties. South Africa’s “festive season now poses the greatest threat to the health and wellbeing of our nation,” he warned this month.