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 number of reported measles cases in the United States has hit 1,288 in the first six months of this year, the most since the disease was declared eliminated in 2000.