Measles is a respiratory virus that can survive in the air for up to two hours. Up to 9 out of 10 people who are susceptible will get the virus if exposed, according to the U.S. Centers for Disease Control and Prevention.

Two separate outbreaks of measles in the U.S. Southwest have now accounted for nearly 100 confirmed cases and hospitalized 16 people.

As measles cases in Texas and New Mexico continue to increase, health officials are urging caution and vaccination. Here is what to know.