View full lesson: https://ed.ted.com/lessons/why-do-you-need-to-get-a-flu-shot-every-year-melvin-sanicas

All year long, researchers at hospitals around the world collect samples from flu patients and send them to top virology experts with one goal: to design the vaccine for the next flu season. But why do we need a new one every year? Vaccines for diseases like mumps and polio offer a lifetime of protection with two shots early in life; what’s so special about the flu? Melvin Sanicas explains.

Lesson by Melvin Sanicas, directed by Andrew Foerster.