The outbreak in Kentucky involves four confirmed cases in Fayette and Woodford counties, marking the state’s first significant occurrence this year. The announcement coincides with multiple large outbreaks in North America, including ongoing surges in parts of Texas, New Mexico, and several Canadian provinces. Texas, one of the worst-affected states, added three more measles cases this week, bringing its 2025 total to 753 cases across 36 counties, with the majority concentrated in West Texas. Of these, Gaines County alone has recorded 414 cases, with transmission originating in an undervaccinated Mennonite community. The state has reported two child deaths and over 99 hospitalizations due to complications associated with measles.
Other significant outbreaks include Ontario and Alberta in Canada, and Chihuahua in northern Mexico. Ontario has recorded over 2,200 cases since October, including one infant death, while Alberta has seen 1,169 cases. The Mexican state of Chihuahua has reported 2,810 cases and eight deaths, further reflecting a troubling regional trend.
Measles is a highly contagious airborne virus that spreads rapidly when infected individuals breathe, cough, or sneeze. The virus can be effectively prevented through vaccination, typically administered in two doses during childhood. Despite the availability of vaccines, the resurgence is largely attributed to declining immunization rates and increased international travel.
In the United States, active outbreaks, defined as three or more related cases, have been reported in Arizona, Colorado, Georgia, Illinois, Iowa, Kansas, Michigan, Montana, New Mexico, North Dakota, Oklahoma, and Utah. Many of these cases involve unvaccinated individuals, some of whom have required hospitalization or succumbed to the disease.
New Mexico has recorded 94 measles cases so far in 2025, including a concentrated outbreak in a Luna County jail that has grown to 13 unvaccinated adult cases. The state has reported one adult death related to measles in early March, and seven hospitalizations to date, with the majority of cases occurring in Lea County. Other counties with confirmed cases include Sandoval, Eddy, Doña Ana, Chaves, Curry, and San Juan.
Arizona reported four cases in Navajo County, all linked to international travel and all involving unvaccinated individuals. Colorado has seen 16 cases in total this year, including an outbreak connected to a flight from Turkey and spread at Denver International Airport. An unrelated case was confirmed in a vaccinated Boulder County resident with recent travel to Europe. Georgia has reported three confirmed cases in the Atlanta metro area.
Illinois reported an outbreak in the southern part of the state that grew to eight cases, in addition to two isolated cases in Cook County. Iowa reported four related cases in a single household in Johnson County. Kansas saw its count rise to 83 cases, primarily clustered in Gray County.
Michigan’s confirmed case count stands at 18, including eight linked to outbreaks in Montcalm and Grand Traverse counties. Montana, which hadn't seen a measles case in decades, has reported 24 this year, with most occurring in Gallatin County. Flathead, Yellowstone, and Hill counties have also reported cases.
North Dakota has confirmed 34 cases, mostly among unvaccinated individuals, with clusters in Williams, Grand Forks, Cass, and Burke counties. Utah has documented nine cases, with three known clusters and some hospitalizations, including two pregnant individuals.
Additional measles cases have been reported in Alaska, Arkansas, California, Florida, Hawaii, Louisiana, Maryland, Minnesota, Missouri, Nebraska, New Jersey, New York, North Carolina, Oregon, Rhode Island, South Dakota, Vermont, Virginia, Washington, and Wyoming. Some earlier outbreaks in Indiana, Ohio, Pennsylvania, and Tennessee are now considered over, with no new cases reported for over six weeks.
Many outbreaks in the U.S. have been traced back to unvaccinated travelers returning from countries with ongoing measles transmission. The CDC noted a substantial increase in imported cases compared to last year. In 2019, the U.S. nearly lost its measles elimination status due to a similar spike.
Vaccination remains the most effective defense against measles. The measles, mumps, and rubella (MMR) vaccine is recommended for children starting at 12 to 15 months of age, with a second dose between ages four and six. Adults concerned about immunity may safely receive another dose, especially if previously vaccinated with a less effective version before 1968. Those born before 1957 are typically considered immune due to widespread childhood exposure.
The virus struggles to spread in communities with high vaccination rates — generally above 95 percent — thanks to herd immunity. However, recent declines in childhood vaccination coverage since the pandemic have left more populations vulnerable, and public health officials are urging communities to act swiftly in raising immunization rates to avoid further escalation of what is already one of the most severe measles years in recent U.S. history.
