U.S. measles cases passed 4,000 this year. In November, health officials decide whether the country is still measles-free

Measles has had its worst year in the United States in more than two decades. The Centers for Disease Control and Prevention reported 4,080 confirmed cases in 2026 as of October 8, in an update published the following day. That is already more than the total for all of 2025, and the highest annual count since the country declared the disease eliminated in 2000, according to tracking by Johns Hopkins’ International Vaccine Access Center.

Next month, the question of whether the United States can still call itself measles-free will be formally reviewed. The Pan American Health Organization has said it will assess the elimination status of the United States and Mexico in November, during the annual meeting of the regional commission that verifies elimination in the Americas.

What “eliminated” means

Elimination does not mean zero cases. It means the disease is no longer spreading continuously within a country. Measles cases in an eliminated country come from travelers who catch it elsewhere, and the outbreaks they spark eventually burn out. A country loses elimination status when a single chain of transmission persists for 12 months or more, which indicates the virus has re-established itself.

That is why the timing of the review matters. According to PAHO, the period under review for the United States runs from the onset of the outbreaks reported starting January 20, 2025. If health authorities conclude that transmission linked to those outbreaks has continued for more than a year, the United States would lose its status. The CDC’s analysis feeds into the regional commission’s decision.

The region has already crossed that line. In November 2025, PAHO announced that the Region of the Americas had lost its measles elimination status, driven by the re-establishment of endemic transmission in Canada. Neither the United States nor Mexico has yet been ruled to have lost national status, but researchers writing in The Lancet and the Johns Hopkins center have said they expect the United States to.

Where the cases are

This year’s cases are concentrated in a handful of large outbreaks. By late July, according to Axios’s analysis of CDC and state data, South Carolina had reported 670 cases and Utah 522, together accounting for about half of the national total at that point. Seven states, South Carolina, Utah, Texas, Virginia, Florida, Pennsylvania and Arizona, made up more than 84% of cases.

The national total has continued to rise since then. In 2025, the country recorded more than 2,000 cases across 45 states, with three deaths, all in unvaccinated people. Different sources give slightly different figures for 2025, reflecting when they were tallied.

Why measles spreads so easily

Measles is among the most contagious human diseases. The virus spreads through the air and can linger in a room after an infected person leaves. People are contagious before the characteristic rash appears, so they can spread it before they know they are sick. Complications can include pneumonia and brain swelling, and young children and people with weakened immune systems are at highest risk.

High vaccination coverage keeps imported cases from turning into outbreaks. When coverage falls in a community, the virus finds enough susceptible people to keep going.

Recognizing measles early helps limit spread. The illness typically begins with high fever, cough, runny nose and red, watery eyes, followed several days later by a rash that starts on the face and spreads downward. Anyone with those symptoms after possible exposure, or after travel to an area with an outbreak, should call a health care provider before going in.

What protects you

The CDC states that two doses of measles-containing vaccine are 97% effective at preventing measles, with a range of 67% to 100% across studies, and one dose is 93% effective. The CDC recommends two doses of MMR vaccine for children, the first at 12 to 15 months of age and the second at 4 to 6 years.

For adults, the questions are usually about records and travel:

• Check your records. Adults without evidence of immunity should talk to a health care provider about vaccination. Your state immunization registry or a past employer or school may have records.
• Before international travel, the CDC advises that infants 6 to 11 months old get an early dose and that older children and adults be fully vaccinated.
• If you are exposed, contact a health care provider promptly. Vaccination soon after exposure can prevent illness in some people.
• Call ahead before visiting a clinic or emergency room with suspected measles, so staff can prevent spread in the waiting room.

What would change if status is lost

Practically, little would change overnight. The vaccine recommendations and outbreak responses would be the same. Losing status would be a formal acknowledgment that measles is again circulating domestically, which affects how the country is viewed in global health reporting and how public health agencies plan. Regaining status requires interrupting transmission for at least 12 months and demonstrating it through surveillance.

For employers, schools and child care providers, the more immediate concern is outbreaks themselves: exclusion of unvaccinated contacts during an outbreak, staff absences and the need to verify immunity records. Those are decisions made by local and state health departments, which publish guidance during outbreaks in their areas.

The CDC updates its national case count weekly. State health departments in outbreak areas publish more frequent local updates.