CDC counts 4,588 US measles cases in 2026, double all of 2025, as Pennsylvania outbreak passes 1,260

Since the first confirmed cases of 2026, the U.S. count has climbed to 4,588 as of Oct. 22, according to the CDC's latest update, published Oct. 23. That is double the 2,289 cases recorded for all of 2025 and more than 16 times the 285 recorded in 2024.

The pace has not slowed. The CDC counted 4,080 cases in early October and 4,410 as of Oct. 15.

What the CDC numbers show

Cases have been reported by 47 jurisdictions. Eighteen were among international visitors. The CDC has logged 43 new outbreaks this year, and 96% of cases (4,404 of 4,588) are tied to outbreaks. Of those, 3,020 come from outbreaks that began in 2026 and 1,384 from outbreaks that started in 2025.

In the CDC's earlier October breakdown, about 95% of patients were unvaccinated or had unknown vaccination status. Two percent had one MMR dose and another 2% had two doses. Ten percent of patients were hospitalized, 414 people at that point.

By age, about 17% of cases were children under 5, 42% were ages 5 to 19, and roughly 40% were adults 20 and older.

The CDC says its count includes only confirmed cases that jurisdictions have notified it about. It is aware of probable cases that are not included.

Pennsylvania: biggest and deadliest in 30 years

The outbreak in Pennsylvania began in April and is centered in Lancaster and Chester counties. State data cited by Reuters showed 1,260 cases and 238 hospitalizations as of Oct. 16. On Oct. 7, the state health department had reported 1,078 cases in 41 counties, 207 hospitalizations and five measles-associated deaths.

The Franklin County Coroner's Office described one death as the first in the county in many years involving a patient with a recent measles diagnosis that meets the Pennsylvania Department of Health's definition of a measles-associated death. A sixth death is under review.

Historically, 1 to 3 of every 1,000 unvaccinated people who contract measles die. With five deaths among roughly 1,300 reported cases, Pennsylvania's rate is at least 1.5 times higher than that benchmark and possibly up to 5 times higher, by CNN's calculation.

Dr. Matthew Ferrari, director of Penn State's Center for Infectious Disease Dynamics, said the difference is not the virus itself. "There clearly is a shift — not in the biology but a shift in the epidemiology that we're seeing here in Pennsylvania," he said.

Dr. Remy Pasco of the University of Colorado Boulder pointed to the community's unique relationship with the health care system. The outbreak has touched Amish and broader Plain communities, and hospitalization rates are higher than expected, he said.

How big is it really?

Nobody knows. Pasco said U.S. measles data is "outdated" because the disease is not endemic here, and any estimate comes "with a big grain of salt." Pennsylvania's health department said a CDC Epi-Aid investigator arrived this week to assess the outbreak's true scale and trajectory and to evaluate local vaccination efforts.

New York is also in the mix. Gov. Kathy Hochul declared a statewide disaster emergency in early October after the state reported 108 cases through Oct. 3.

The long view

A forecast published in JAMA projects that if vaccination rates do not improve, measles could become endemic again in the U.S. The model estimates 851,300 cases, more than 170,000 hospitalizations and 2,550 deaths over 25 years. It is a projection, not a count.

The global picture is not better. A study by the GBD 2023 Measles Collaborators in Nature Medicine, published Oct. 21, estimated 15.6 million measles cases among children under 5 worldwide in 2023, about 40% more than in 2019, and 118,000 deaths. The figures are modeled estimates, not direct counts, and the authors link the rebound to pandemic-era disruption of childhood vaccination without proving a single cause. The study was funded by the Gates Foundation and Gavi.

The largest current outbreaks are in Bangladesh (more than 65,430 cases), Indonesia (46,578) and Guatemala (31,222).

Europe's exposure

The European Centre for Disease Prevention and Control reports first-dose coverage of 92% and second-dose coverage of 88% in Europe. The agency calls that "strong population protection," but it is below the 95% two-dose level needed to prevent sustained transmission. National averages can also hide pockets with far lower coverage.

The ECDC said whether an imported case spreads "depends primarily on immunity levels in the affected community." Kitty Mohan of the Standing Committee of European Doctors noted that people are contagious for about four days before the rash appears, so they can cross borders before knowing they are sick.

Italy illustrates the gaps. Over a quarter of the 2,300-plus EU cases between September 2025 and August 2026 were in Italy, with an incidence of 11.1 per million against a European average of 5.1. Its national second-dose average is 84.45%, according to the GAT Report, and Prof. Matteo Bassetti of San Martino Polyclinic Hospital in Genoa warned of complications including pneumonia and encephalitis.

The open question is the size of the Pennsylvania outbreak. The Epi-Aid findings will show how many cases the official count has missed and whether the state's vaccination push is reaching the affected communities.