S3 E7

Why Does the Flu Come Back Every Year?

What is Influenza, and why does it always seem to be one step ahead of us?

SICK is a new series that looks at how diseases actually work inside our body. We'll be visiting medical centers and talking to top researchers and doctors to uncover the mysteries of viruses, bacteria, fungi and our own immune system. Come back every Tuesday for a new episode and let us know in the comments which diseases you think we should cover next.