Already in 2025, the United States has reported more measles cases than in any full year since the early ‘90s, according to federal data. And that record-setting case count has been driven by a massive outbreak that began in Texas.

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.