The number of measles cases documented in the U.S. in 2019 has now surpassed 1,000, the Centers for Disease Control and Prevention announced Wednesday. Just a week after the CDC said measles cases had reached the highest level seen in nearly three decades, there are now 1,001 confirmed cases. “The 1,000th case of a preventable disease like measles is a troubling reminder of how important that work is to the public health of the nation,” Health and Human Services Secretary Alex Azar said in a statement. “We cannot say this enough: Vaccines are a safe and highly effective public health tool that can prevent this disease and end the current outbreak.” Most of the cases reportedly stem from an outbreak in New York City and Rockland County, New York—with other cases recorded in states like Michigan and Washington.