Rise in Measles Cases in the U.S. Surpasses 2025 Record

The number of measles cases in the United States has exceeded the previous record set in 2025, with five months remaining in 2026. As of Thursday, the Centers for Disease Control and Prevention (CDC) reported 2,318 cases. The total for 2025 was 2,289 cases, marking the worst year for measles in over thirty years. Major outbreaks in states like South Carolina, Utah, and Arizona, as well as smaller clusters elsewhere, contribute to the rising numbers.

The CDC will meet with international health officials in November to evaluate whether the U.S. and Mexico have lost their measles-free status. The U.S. had eliminated local measles spread by 2000 through high vaccination rates, but rates have fallen below the 95% coverage needed to prevent outbreaks.

Undercount of Measles Cases

Although measles cases are increasing, the true extent of the outbreak might be hard to determine. Public health departments acknowledge that official case counts are incomplete. Some individuals do not seek treatment, which is not unique to measles. Experts warn that the spread is likely greater than known because measles is highly contagious and vaccination rates have declined.

In Utah, over 700 cases have emerged over the past year according to the state health department. Mathematical modeling and genetic analyses suggest a large outbreak on the Utah-Arizona border could be three to four times larger. South Carolina, experiencing the largest outbreak in 35 years, recorded 997 cases. However, the state health department notes this is likely an undercount.

“What we’re able to count and report is almost always an underestimate of what actually occurred.”

Data gaps complicate reliable outbreak estimation. Hospitalization rates can provide insight, but states do not require measles hospitalizations to be reported.

Analyzing Previous Outbreaks

In Texas, researchers continue to examine the 2025 outbreak, initially recorded at 762 cases. Early findings suggest it might have been nearly double that count. Without sufficient community vaccination, managing measles becomes challenging.

The CDC defines an outbreak as three or more linked cases. In communities with low vaccination rates, this threshold often means more cases have been missed. Health officials struggle to confirm cases due to unwillingness or inability of people to get tested and share information.

In Gaines County, Texas, 182 probable cases among minors went unconfirmed due to inadequate information. The confirmed count for the outbreak in the county remains at 414 cases.

Importance of Vaccination

Dr. Mark Roberts from the University of Pittsburgh stresses the importance of vaccination for communities and individuals. Some people cannot receive vaccines due to age, immune system issues, or insufficient immunity response. These groups are at high risk during outbreaks. Roberts likens skipping vaccination to refusing safety features in a car, emphasizing the impact on others rather than oneself.

Efforts to maintain high vaccination coverage are crucial to preventing and limiting outbreaks.