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. has now recorded more confirmed measles cases this year than in any year in well over a quarter-century.

Measles cases in the United States have reached their highest number in more than 30 years, according to new federal data published Wednesday.