The number of measles cases reported in the U.S. this year has reached 1,001, the Centers for Disease Control and Prevention reported on Wednesday.

Health and Human Services Secretary Alex Azar said his agency has been “promoting the safety and effectiveness of vaccines, amid concerning signs that there are pockets of undervaccination around the country.”

“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,” he 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,” he said, adding that the measles vaccine is given safely to millions of children and adults every year.

* Cases as of December 29, 2018;
** Cases as of June 5, 2019.
Source: Centers for Disease Control and Prevention
Graphic: Jiachuan Wu / NBC News

Last week, the CDC reported that measles cases had reached their highest level in 27 years, causing concern among public health officials that the country could soon lose its measles elimination status.

Read the full story here.