Mutant coronavirus in the United Kingdom sets off alarms but its importance remains unclear

Scientists have never seen the virus acquire more than a dozen mutations seemingly at once. They think it happened during a long infection of a single patient that allowed SARS-CoV-2 to go through an extended period of fast evolution, with multiple variants competing for advantage. One reason to be concerned, Rambaut says, is that among the 17 are eight mutations in the gene that encodes the spike protein on the viral surface, two of which are particularly worrisome. One, called N501Y, has previously been shown to increase how tightly the protein binds to the ACE2 receptor, its entry point into human cells. The other, named 69-70del, leads to the loss of two amino acids in the spike protein and has been found in viruses that eluded the immune response in some immunocompromised patients.