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.

Many viruses, particularly RNA viruses, mutate at a very high rate per genome per replication. One possible explanation is that high mutation rates are selected to meet the challenge of fluctuating ...

When HIV jumped from chimpanzees to humans sometime in the early 1900s, it crossed a gulf spanning several million years of evolution. But tobacco ringspot virus, scientists announced last week, has ...