Scientists estimate somewhere between 5%-35% of people do not get sick from the flu despite being exposed to the virus that causes it. Now, researchers may have figured out why. The team looked at mouthwash samples from 19 healthcare workers who, despite frequent contact with infected patients, report never getting flu symptoms. Today on Short Wave, we talk about how what they found could help scientists develop treatments and strategies to protect people who do get the flu. If you liked this episode, check out our show on an effort to map the entire immune system.Interested in more health science? Email us your question at shortwave@npr.org.Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.To manage podcast ad preferences, review the links below:See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy