measles outbreak

Lisa Gillespie, WFPL for Side Effects Public Media

It’s a rainy spring evening in Louisville, less than two weeks from one of city’s biggest events: the Kentucky Derby. On May Fourth, people from across the U.S. and world stream into town to watch a day of horse racing.

Courtesy of Jessica Barnes

Measles is a potentially deadly illness that is spreading in many parts of the world. Thanks to vaccines, the disease was eliminated from the U.S. almost two decades ago.

But measles outbreaks have sprung up ever since.