There have been 935 confirmed measles cases reported in the United States as of May 1, according to the Centers for Disease Control and Prevention (CDC).
The confirmed measles cases were reported by 30 jurisdictions: Alaska, Arkansas, California, Colorado, Florida, Georgia, Hawaii, Illinois, Indiana, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, New Jersey, New Mexico, New York City, New York State, Ohio, Oklahoma, Pennsylvania, Rhode Island, Tennessee, Texas, Vermont, Virginia, and Washington.
There have been 12 outbreaks (defined as 3 or more related cases) reported this year so far, the CDC said.
The cases are part of ongoing measles outbreaks in North America, with over 2,500 cases reported across Canada, Mexico, and the United States.
The current measles wave first appeared in Ontario, Canada, last fall before spreading to the United States, where cases were identified in Texas and New Mexico in late January. By mid-February, the virus had reached Mexico’s Chihuahua state.
“Diseases know no borders,” said Dr. Hector Ocaranza, El Paso’s top public health official. “So as people are mobile, they’re going to be coming and receiving medical attention in El Paso but they may be living in Juarez.”
The virus’s cross-border spread is especially evident in border communities. El Paso, Texas, has reported 38 cases, the highest count in Texas outside of West Texas. Neighboring Ciudad Juarez in Mexico has confirmed 14 cases as of April 29.
Texas accounts for the majority of the U.S. cases, with 683 confirmed cases across 26 counties, and Gaines County represents approximately 60 percent of those cases.
In Canada, Ontario has reported 1,020 cases through April 23. Mexico’s Chihuahua state has documented 786 cases as of April 30, according to state health ministries.
Health officials have identified certain Mennonite Christian communities as key factors in the cross-border transmission. Chihuahua health officials traced their first case to an 8-year-old Mennonite child who visited family in Seminole, Texas, became ill, and then spread the virus at school.
Outbreaks Expand
The outbreak has expanded beyond initial hotspots, with active outbreaks now occurring in 12 states. These include Texas, New Mexico, Indiana, Michigan, Montana, Ohio, Pennsylvania, Tennessee, Oklahoma, and Kansas.
Michigan’s outbreak of four cases in Montcalm County has been directly linked to the Ontario outbreak, according to Dr. Natasha Bagdasarian, the state’s chief medical executive.
“If we think about measles as a forest fire, we’ve got these burning embers that are floating in the air right now. Whether those embers result in another wildfire just depends on where they land,” Bagdasarian said.
According to the CDC, 93 percent of confirmed U.S. cases in 2025 are outbreak-associated. There have been 12 outbreaks reported so far this year, compared to 16 in 2024.
Of the 935 U.S. cases in 2025, 30 percent are under 5 years old, 38 percent are ages 5-19, 30 percent are 20 or older, and 1 percent are of unknown age. Thirteen percent of all cases (121 of 935) have required hospitalization. The highest hospitalization rate is among children under 5 years old (23 percent).
There have been three confirmed deaths from measles in the United States this year and one death in Mexico.
Health departments are working across borders to address the outbreaks. In El Paso, officials are conducting vaccination clinics in community spaces like malls and parks, offering free vaccines regardless of which side of the border residents live on.
Each measles case in the United States costs an estimated $30,000 to $50,000 to investigate and address.
The Associated Press contributed to this report.
