(CNN) The United States has reached a concerning new milestone: More measles cases have been reported this year than any other since the disease was declared eradicated 25 years ago. This is due to a combination of declining childhood vaccination rates and a sizable, smoldering outbreak that was started in an undervaccinated area of West Texas.
The Johns Hopkins University Center for Outbreak Response Innovation reports that at least 1,277 confirmed measles cases were reported in the United States in 2025. Even though the year is just halfway over, the number of cases has already eclipsed the previous high of 1,274 instances set in 2019.
According to experts, the number of instances this year is probably going to be significantly underreported because so many are going undetected. The number of measles deaths in the United States during the past 25 years is equal to the three measles deaths that have occurred this year—two youngsters in Texas and one adult in New Mexico—all of whom were not vaccinated.
Measles has not been continuously transmitted for more than a year at a time since it was declared eradicated in the United States in 2000. According to the US Centers for Disease Control and Prevention, vaccine development had a major role in making this status a historic public health accomplishment. The most extensively used measles-mumps-rubella (MMR) vaccination initially became accessible in the United States in the 1970s.
According to CDC data, since measles was proclaimed eradicated, an average of 180 cases were reported annually until this year.
Large outbreaks that threatened elimination status occurred in New York in 2019. These outbreaks were focused in Orthodox Jewish communities in Brooklyn and Rockland County, which had been the focus of years of anti-vaccine misinformation.
With over 750 confirmed cases linked to an epidemic that began in late January, Texas has seen the great bulk of measles cases this year. The United States may lose its measles eradication designation if the number of cases linked to that outbreak keeps rising through January of the following year.
The state health department reports that Gaines County, where vaccination rates are much below the recommended threshold, has seen the majority of those cases—more than 400 since the year began. Gaines County has one of the highest rates of MMR vaccine non-adherence in the state during the 2024–25 school year, with almost one in four kindergarteners lacking the necessary vaccination.
The West Texas outbreak has also been linked to dozens of cases in New Mexico and Oklahoma, and there may be a connection between cases recorded in Kansas and the outbreak.
Additional coverage for thousands of patients has resulted from the establishment of special vaccination clinics in response to the outbreak. Additionally, new vaccination guidelines have been implemented in many of the impacted counties, enabling infants to receive their first immunization as early as six months of age rather than waiting until one year. According to state health department data, New Mexico has administered almost twice as many MMR immunizations this year than it did at this time last year.
Additionally, early immunization rates among infants in Texas increased, according to a recent analysis of medical records conducted by the health-care data and analytics firm Truveta. About 1 in 5 Texas infants who received their first measles vaccination in March and April had received it early, before their first birthday, and the state’s 6-month-old MMR vaccination rates are more than eight times higher this year than they were in 2019.
However, infections have continued to mount nationwide as the rate of new cases linked to the West Texas outbreak has slowed. This year, at least 38 states have reported at least one case, and there have been at least 27 outbreaks overall, which are defined as three or more connected cases.
Last month, Colorado saw a sharp increase in instances after an out-of-state tourist flew while contagious, resulting in numerous cases among passengers on the same airline, more cases among others in the airport at the same time, and a ripple effect on the larger community.
Travel to Chihuahua, Mexico, where there is also a significant outbreak centered among the local Mennonite population, was connected to further cases among Colorado residents. Another significant outbreak that was connected to several cases in Michigan is currently occurring in Ontario, Canada. This year, measles has claimed the lives of nine people in Mexico and at least one in Canada.
Due to elevated measles case rates, Mexico warned travelers visiting the US and Canada to exercise caution in April. Additionally, the CDC has strengthened its travel advice, recommending that anybody going abroad get two doses of the MMR vaccine.
Most cases are in unvaccinated people
According to the CDC, just around 8% of reported cases this year have been among individuals who have had one or two doses of the MMR vaccine, with the great majority of cases occurring in unvaccinated individuals. According to CDC data, at least 155 measles cases—roughly one out of every eight cases—have resulted in hospitalization this year, with children under the age of five accounting for 28% of cases.
Although measles is one of the most contagious illnesses in the world, the MMR vaccine is safe and very successful; one dose is 93% effective against measles, and two doses are 97% effective.
In order to help avoid outbreaks of the extremely contagious disease, the US Department of Health and Human Services has established a goal that at least 95% of kindergarten-aged children would have received two doses of the measles-mumps-rubella (MMR) vaccination. For the fourth consecutive year, the US has now failed to meet that criterion.
According to data released by the CDC in October, a record number of US kindergarteners were exempt from needed vaccinations during the 2023–24 school year, meaning that over 125,000 new students were not covered for at least one state-mandated vaccine.
Both the HHS secretary and the CDC director at the time issued comments highlighting the safety and efficacy of the MMR vaccination and urging Americans to be vaccinated when the measles case count hit its prior high in 2019 during the first Trump administration.
But HHS Secretary Robert F. Kennedy Jr. has a tangled and lengthy history with measles immunizations, and the CDC still has a director.
Despite years of campaigning against measles vaccines, Kennedy’s biggest support for vaccination came in April, when there had been roughly 600 cases in the US. Additionally, public health officials nationwide expressed worry when Kennedy fired an expert group of vaccine advisers last month that has traditionally influenced the federal government’s vaccine recommendations.
“This move will further fuel the spread of vaccine-preventable illnesses,” warned Dr. Bruce A. Scott, president of the American Medical Association, in a statement at the time, citing a continuing measles outbreak and dropping routine child immunization rates.
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