While measles symptoms typically resolve in a few weeks, the virus can cause pneumonia, making it difficult for patients, especially children, to get oxygen into their lungs. It may also lead to brain swelling, which can cause lasting damage, including blindness, deafness and intellectual disabilities.

The U.S. is having its worst year for measles spread in more than three decades, with a total of 1,288 cases nationally and another six months to go in 2025.