Some viruses mutate more rapidly than others. Learn more about why that is and what that means for your health. Have you ever wondered why you have to get a flu shot every year, but some vaccines are ...

It's dusk in central Bangladesh, in a community within the district of Faridpur. A 50-year-old man sits outside his home beside a rice paddy. His name is Khokon. A fiery beard, dyed a bright orange, ...

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.