The new coronavirus variant linked to a surge in Covid-19 cases in South Africa is not only more infectious than previous forms of the virus but could make some vaccines less effective.

Scientists racing to understand the new strain said they still expected the current crop of approved vaccines to work but were worried that a specific mutation, also identified in a new variant in Brazil, could affect the way the virus responds.

“At this moment, we think that a vaccine could be a little less effective,” Professor Tulio de Oliveira, of the University of KwaZulu-Natal, who is leading South Africa’s scientific effort to understand the 501Y.V2 strain, told the Financial Times. “[But] between all the varieties of vaccines that are coming to the market, we still have strong belief that some of them will be very effective.”