A team of researchers has examined why the UK and South African variants of SARS-CoV-2, the virus that causes Covid-19, are more infectious and, in many cases, more deadly. The study indicated that the UK variant, also known as B.1.1.7, has many mutations in the spike glycoprotein, but most important is one mutation, N501Y, in the receptor binding domain that interacts with the ACE2 receptor.

"This N501Y mutation provides a much higher efficiency of binding, which in turn makes the virus more infectious," said Victor Padilla-Sanchez, a research scientist at The Catholic University of America. The UK variant was first detected in September 2020, and is now causing 98 per cent of all Covid-19 cases in the UK. The World Health Organization (WHO) said the UK variant is one of several variants of concern along with others that have emerged in South Africa and Brazil. The South Africa variant emerged in October 2020, and has more important changes in the spike protein, making it more dangerous than the UK variant.