Just as antibiotics have bred resistance in bacteria, vaccines can potentially lose their effectiveness over diseases they controlled. Researchers are working to head off the evolution of new threats.
About the author
Melinda Wenner Moyer is a science writer based in New York's Hudson Valley. She is a contributing editor at Scientific American and a columnist at Slate. She is a 2018 visiting scholar at NYU's Arthur L. Carter Journalism Institute and an Alicia Patterson fellow.