LM,

"The resurgence of measles in the United States is primarily driven by declining childhood immunization rates and growing vaccine hesitancy, which leave vulnerable pockets of unvaccinated people exposed to imported virus strains from international travel. According to the Centers for Disease Control and Prevention, while the U.S. eliminated endemic measles in 2000, drops in routine vaccination coverage have allowed imported cases to trigger significant outbreaks.

International Travel: Travelers who contract measles in global hotspots bring the virus back into the U.S., sparking domestic transmission chains."

As an international traveler, international travel is a big spreader of disease. I've read about earlier outbreaks and we just have too any dumb adults who don't get vaxxed and don't get kids vaxxed. Dumb Americans, not illegal aliens. We should be wondering why it's happening elsewhere in the world, not here, but we don't, and it's because we have too many dumb Americans.