US Measles Cases Reach 5182 in 2026 Highest Total Since 1991

The Centers for Disease Control and Prevention reported 5,182 confirmed measles cases in the United States for 2026 as of November 5, the highest annual total since 1991. The figure rose by 330 cases from the previous week's count of 4,852, a 6.8 percent increase.

Cases have been reported in 45 states and the District of Columbia. Eighteen additional infections involved international visitors. Ninety-six percent of the cases are outbreak-associated. There have been 43 new outbreaks reported in 2026. Of the outbreak-linked cases, 3,608 originated in 2026 and 1,385 began in 2025.

The vast majority of infections, 96 percent, occurred among people who were unvaccinated or whose vaccination status was unknown. Two percent of cases were in people who had received one dose of the measles, mumps and rubella vaccine, and 2 percent were in people who had received the recommended two doses.

Pennsylvania has recorded the highest number of cases at 1,487, with 287 hospitalizations and a sixth measles-associated death reported this week by state health officials. South Carolina has 670 cases and Utah has 536. Wisconsin reported an infant death on Thursday. New York reported its first known measles-associated death in more than 30 years earlier this week.

Nationwide, the CDC has confirmed four measles-associated deaths for 2026 and noted that the number is subject to change. State health departments have reported eight deaths in total: six in Pennsylvania, one in New York and one in Wisconsin. Hospitalizations stand at 562, or 11 percent of all reported cases. More than one in ten children under five who contracted measles required hospital care.

People aged 20 and older accounted for 2,132 cases. Those aged 5 to 19 accounted for 2,104 cases, and children under five accounted for 908. The CDC data show that the 2026 total is already more than double the 2,289 cases recorded for the full year of 2025, with nearly two months remaining.

The resurgence threatens the United States' measles elimination status, which requires the absence of continuous transmission for 12 months. Health officials have tracked ongoing chains of transmission in multiple states. Pennsylvania's outbreak has driven a large share of the national total and has produced the highest number of hospitalizations and deaths.

State health departments continue to update local counts daily. Colorado confirmed a 27th case on November 4 involving a Weld County infant too young for routine vaccination. Other states with significant numbers include Ohio, New York, Kentucky, Texas, Virginia and Florida.

The CDC updates its national tally on a weekly basis. The most recent release incorporated data through November 5. Differences between CDC and state figures on deaths have appeared in previous years when investigations into causality are still underway. Officials in affected states have expanded vaccination clinics and issued alerts for unvaccinated contacts.

Measles is highly contagious. A single infected person can transmit the virus to roughly 90 percent of nearby unvaccinated people. Complications include pneumonia, encephalitis and death, particularly in young children and immunocompromised individuals. The two-dose MMR schedule provides strong protection for the large majority of recipients.

Public health agencies in high-incidence states have focused on identifying unvaccinated clusters and offering catch-up immunization. Hospital systems in Pennsylvania have reported increased demand for isolation rooms and specialist care for measles patients. The infant death in Wisconsin and the first New York death in decades have drawn additional attention to the risk for the youngest children.

The national case count of 5,182 exceeds the total recorded in any year since 1991. Elimination status, achieved in 2000, depends on interrupting endemic transmission. Sustained outbreaks that cross the 12-month threshold can lead to loss of that status. Several current outbreaks began in 2025 and have continued into 2026, complicating the timeline calculation.

Vaccination rates have declined in some communities in recent years. Coverage below 95 percent in a local population can allow measles to spread once introduced. The current data show that nearly all infections are concentrated among people without documented immunity. States with the largest outbreaks have reported lower two-dose coverage in certain counties.

Health departments continue contact tracing for each confirmed case. Exposed individuals without immunity are advised to quarantine and to receive vaccine if eligible. The 11 percent hospitalization rate indicates that a substantial share of infections produce serious illness requiring medical intervention. Children under five face elevated risk of complications.

The CDC has not projected an end-of-year total. Weekly increases of several hundred cases have continued. Officials in Pennsylvania, the hardest-hit state, have not indicated that the local outbreak is under control. Additional deaths reported by states this week bring the documented total to eight while the CDC's confirmed count remains four pending further review.