Measles cases in the United States are the highest they’ve been since the country eliminated the disease in 2000. The U.S. has reported 1,277 cases since the start of the year, according to NBC News’ tally of state health department data.

The University of Texas and Austin Public Health created a measles simulator for school districts and private schools around the county to better understand their risks.

U.S. measles cases hit 1,277—the worst outbreak since the disease was declared eliminated in 2000, surpassing 2019's peak.

The Centers for Disease Control and Prevention says the U.S. is currently experiencing its worst measles outbreak in more than 30 years, according to the Associated Press. On Wednesday, the CDC said the 2025 case count has surpassed the 2019 count, when there were 1,274 cases for the year.

The U.S. is having its worst year for measles spread in more than three decades, with a total of 1,288 cases nationally and another six months to go in 2025.

The Pan American Health Organization says the most affected age groups are children under the age of 5 and adolescents aged 10 to 19. Gaps in routine immunization are helping to fuel outbreaks of a disease that was considered eliminated in America in 2000, when less than 100 cases were reported, the organization says.