Strain that emerged in February responsible for up to 85% of global cases Dr. Ilya Finkelstein: The virus continues to mutate as it rips through the world LONDON: A mutated strain of coronavirus may be responsible for 85 percent of cases worldwide, scientists in the US have warned. In a study at Houston Methodist Hospital, Texas, researchers said 99.9 percent of 5,000 patients examined had contracted the D614G strain. It is thought to have first emerged in Europe in February this year, before crossing the rest of the world within days. The scientists said D614G had been found globally just a month after it mutated, and was responsible for 70 percent of all cases within three. “The virus continues to mutate as it rips through the world,” said the study’s co-author Dr. Ilya Finkelstein. What makes D614G more contagious than its predecessors is thought to be that it leads to higher levels of the virus in the upper respiratory tract of those infected, increasing its spread when the person exhales, coughs or sneezes. COVID-19 is caused by the virus using spike proteins to latch on to human receptor cells, using them as a host through which to multiply. It is in the spike proteins that the mutation D614G occurred, making it easier for the virus to attach itself to the receptor cells. However, a study by the Commonwealth Scientific and Industrial Research Organisation said the mutation would not affect efforts to develop a vaccine for COVID-19. “Despite this D614G mutation to the spike protein, we confirmed through experiments and modelling that vaccine candidates are still effective,” said Prof. Seshadri Vasan, who led the study. “We’ve also found the strain is unlikely to require frequent ‘vaccine matching’ where new vaccines need to be developed seasonally to combat the virus strains in circulation, as is the case with influenza.”