Watch for measles symptoms like high fever, ear infections, runny nose, pink eye, and a rash that can go from head to toe. If you have any, call your doctor immediately.

Health authorities warned of further spread. Most U.S. measles cases this year involved people 19 and under and those without a confirmed vaccination.

Texas' measles outbreak is now at 90 cases, the highest yearly case count since 1992. Experts say the number is likely to grow more. Here's why.