Measles is a highly contagious airborne disease caused by a virus, and can be severe or even fatal. According to the U.S. Centers for Disease Control and Prevention (CDC), the best way to protect yourself against measles is to get vaccinated. Here, TIME answers all your questions about the vaccine.

As of Feb. 20, there were a total of 93 measles cases reported in eight states: Alaska, California, Georgia, New Jersey, New Mexico, New York, Rhode Island and Texas, according to the Centers for Disease Control and Prevention. For comparison, 285 cases were reported in the U.S. in 2024.

Measles may be a very rare disease today, but it is highly contagious and can be potentially deadly. And Senator Bill Cassidy says it’s headed for Louisiana.