In Texas, at least 90 cases of measles have been reported in recent weeks across the northwest part of that state.

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

According to the CDC, if you were born after 1957, one dose is considered sufficient to be considered protected from measles. Some adults may need a second dose. The CDC says adults who are going to be in high-risk settings for transmission should make sure they’ve had two doses at least 28 days apart.