U.S. Measles Cases Reach Record Levels
The United States has seen its highest number of measles cases, surpassing the previous record set in 2025, with still five months remaining in 2026. The Centers for Disease Control and Prevention (CDC) reported 2,318 cases as of Thursday.
In 2025, there were 2,289 cases, marking the worst year for measles in over three decades. The situation has worsened in 2026, with significant outbreaks occurring in South Carolina, Utah, and Arizona.
In November, global health officials will assess whether the U.S. and Mexico should lose their measles-free status, initially achieved in 2000 through high vaccination rates. These rates have since dropped below the critical 95% needed to prevent outbreaks.
Measles cases may be higher than reported due to undercounting. Public health officials have acknowledged that official counts are often incomplete.
The contagious nature of the virus and declining vaccination rates further complicate accurate tracking. National rates for measles, mumps, and rubella vaccinations fell to 92.5% among kindergartners in the 2024-25 school year, down from 95.2% in 2019-20.
Utah and South Carolina Outbreaks
In Utah, public health officials have battled over 700 cases in more than a year. Mathematical models and genetic analyses suggest the outbreak near the Utah-Arizona border could be substantially larger than current figures suggest, according to state epidemiologist Dr. Leisha Nolen.
South Carolina faced the largest outbreak in 35 years, with 997 cases reported—likely an undercount. The state’s acting health director, Dr. Brannon Traxler, admits the true number may vary.
The absence of required reporting of measles hospitalizations in every state makes estimating the outbreak’s true scope challenging.
Concerns in Texas
Researchers in Texas continue to assess the 2025 outbreak. Preliminary data indicates it may have been nearly twice as large as the reported 762 cases. Mathematical epidemiologist Rémy Pasco from the University of Colorado Boulder explains that undercounts are unsurprising when community vaccination rates fall below 95%.
The CDC defines an outbreak as three or more linked cases. In communities with low vaccination rates, the detection of three cases often hints at a larger, undetected spread.
Public Health Perspectives
Texas’ chief state epidemiologist, Dr. Varun Shetty, emphasizes that official counts often underestimate the actual situation due to reliance on voluntary testing and information sharing. In March 2025, Gaines County in Texas had 182 probable cases without confirmation due to information gaps.
Dr. Mark Roberts, retired director at the University of Pittsburgh School of Public Health, highlights the dangers to vulnerable groups unable to receive vaccinations. He likens the decision to skip vaccination to a car lacking brakes, stressing community protection through high vaccination coverage.
The Associated Press Health and Science Department is supported by the Howard Hughes Medical Institute’s Department of Science Education and the Robert Wood Johnson Foundation. The AP holds sole responsibility for this content.