The measles outbreak in Texas has escalated sharply to 90 cases as health officials worry about the spread to more communities.

Health officials expect a measles outbreak in West Texas to exceed 100 cases because of low vaccine rates and undetected infections. Vaccine misinformation and new laws may make such situations more common and harder to contain.

Texas' measles outbreak is up to 90 cases. Here's what you need to know about the virus, vaccination and boosters.