The flu shot changes every year. But why is the flu special, if other illnesses have much longer-lasting vaccines? This episode takes us into the world of viruses and immunity.

We released this episode about flu vaccines last year but we wanted to share it with you again since it’s flu vaccine season but also because vaccines are in the news a lot lately. Scientists are testing a bunch of vaccines for the new coronavirus right now. This episode gets into the details of how vaccines work and how they’re made.

A friendly lymphocyte fills us in on how flu shots work, and science journalist Anna Rothschild shares how vaccines started around the world. We'll hear from some virus-busting detectives to see how scientists solve the case of how to make next year’s flu shot as effective as possible. Author Maryn McKenna will stop by and drop some flu knowledge, too!

Get your ears ready for a good, thumping mystery sound, and a new Moment of Um: how do straws work?

This episode is sponsored by KiwiCo (KiwiCo.com/brainson), Pillsbury Grands Cinnamon Rolls, Guardian Bikes (GuardianBikes.com/brains) and Varsity Tutors (VarsityTutors.com/brainson). You can support the show at brainson.org/donate