Most of these variants are not significant or widespread. But as the number of people who have been infected — and, presumably, have developed some immunity — increases, the pressure on the pathogen to mutate also increases. Some of the new variants can be more transmissible or lead to more severe illness than earlier versions of the virus.
“This is potentially serious,” Jeremy Farrar, an infectious disease expert who is director of the Wellcome Trust, said in a statement last week. “The surveillance and research must continue, and we must take the necessary steps to stay ahead of the virus.”