As evidence mounts that the omicron variant is less deadly than prior COVID-19 strains, one oft-cited explanation is that viruses always evolve to become less virulent over time. The problem, experts ...

Have you ever wondered why you have to get a flu shot every year, but some vaccines are one-and-done? It all has to do with how and how fast viruses evolve - and that depends on mutation rates.

A phylogenetic tree of SARS-CoV-2 sequences, built with Nextstrain, displays sequences colored by their clade and organized by collection date. Over time, sequences mutate and diverge, forming new ...