As viruses replicate, they change, or mutate. Some mutations give these viral variants an edge, such as being better able to latch on to and infect human cells. That’s what scientists think happened with the coronavirus variant that swept through the U.K. recently and which is now showing up in states across the U.S.

Mutations can also make a viral pathogen stealthier, or better at evading the body’s immune system. That’s what some scientists find worrisome about another mutation seen in the variants that emerged recently in South Africa and Brazil.

source: wsj.com