The United States surpassed a milestone in reported measles cases, with 2025 now having the most cases since the disease was declared eliminated in the U.S. in 2000 and the most cases in more than three decades. As of July 7, 2025, 1,281 cases have been reported, more than the 1,274 measles cases reported in all of 2019, according to a U.S. Measles Tracker hosted by the International Vaccine Access Center (IVAC) at the Johns Hopkins Bloomberg School of Public Health and developed in collaboration with the Center for Systems Science and Engineering (CSSE) at the Whiting School of Engineering.
This interactive dashboard maps the total (in 2025) and recent (in the past two weeks) number of reported measles cases at the county level to provide real-time data. The data are made freely available for use by health officials, researchers, and the public in a Github repository.
“Our U.S. Measles Tracker offers a high-resolution, county-level view of measles outbreaks around the country, which complements other state-level or state-specific reporting,” says Lauren Gardner, professor of civil and systems engineering at Johns Hopkins. “Because diseases don’t respect county and state borders, precise and timely information about ongoing outbreaks across the U.S. is critical for both the general public and public health officials to make informed decisions.”
In addition to case counts, the dashboard also provides data on measles cases by age and by vaccination status. Unsurprisingly, nearly all 2025 cases have occurred in those who are unvaccinated or whose vaccination status is unknown. Cases have been reported across a wide age range, indicating that this outbreak was years in the making due to long-standing gaps in measles vaccine coverage.
“The ongoing outbreak we are seeing in the U.S. underscores the importance of maintaining adequate levels of measles vaccination,” says IVAC Executive Director William Moss, who co-leads the measles tracking project. “The U.S. is at risk of losing its measles elimination status should cases continue at this rate. As vaccine confidence continues to be undermined, immunization is more important than ever to end this outbreak and prevent future outbreaks from occurring.”
The U.S. Measles Tracker will continue to monitor new confirmed cases of measles, with data updated at least twice each week.
This collaborative, interdisciplinary effort reflects contributions from Johns Hopkins researchers at the Center for Systems Science and Engineering (CSSE) at the Whiting School of Engineering, the International Vaccine Access Center (IVAC) at the Bloomberg School of Public Health, and the Bloomberg Center for Government Excellence at Johns Hopkins University.
This story originally appeared on the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health website.