A hospital in Texas on Wednesday confirmed the death of an unvaccinated child who was infected with measles—the first fatality in a two-state measles outbreak that began in January, according to the Associated Press.

A child who wasn't vaccinated died in a measles outbreak in rural West Texas, state officials said Wednesday, the first U.S. death from the highly contagious — but preventable — respiratory disease since 2015.

The outbreak is primarily affecting West Texas, but officials in San Antonio, New Braunfels and San Marcos are monitoring cases after an infected person recently visited the area, according to the Texas Department of State Health Services.