The measles outbreak in the South Plains region of Texas has grown to 223 cases. 29 of those infected have been hospitalized and one school-aged child has died, according to a new update from the Texas Department of State Health Services.

In addition to Texas and New Mexico, the Centers for Disease Control and Prevention (CDC) have confirmed measles cases in Alaska, California, Florida, Georgia, Kentucky, New Jersey, New York City, Pennsylvania, Rhode Island and Washington, though the majority are in Texas and New Mexico.

Amid the outbreak of measles in West Texas, there’s a question of how contagious the disease is — and whether it will spread.