A measles outbreak in West Texas has topped 120 cases and resulted in the first U.S. death from the illness in a decade.

An unvaccinated child has died from measles in West Texas, officials said, marking the first fatality from the disease in the U.S. since 2015. The Texas Department of State Health Services (DSHS) confirmed the death on Wednesday but did not disclose the patient's age.

At least 124 cases have been identified in Texas since late January, mostly among children and teenagers who are unvaccinated or whose vaccination status was unknown.