Nearly a month after the first reported case of measles in the South Plains, health officials have confirmed the first death due to the outbreak.

LUBBOCK, Texas (AP) — A person who was hospitalized has died from measles in West Texas, the first death in an outbreak that began late last month. Texas Tech University Health Sciences Center spokesperson Melissa Whitfield confirmed the death Wednesday. It wasn’t clear the age of the patient, who died overnight.

This is the first death in the U.S. caused by measles since 2015, according to the U.S. Centers for Disease Control and Prevention (CDC).