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Case and death counts change weekly and differ between federal and state sources.
U.S. measles cases have passed 4,400 this year, the most in more than three decades, and federal health officials are now sending help to Pennsylvania, the hardest-hit state. Here is where measles is spreading, what the latest numbers show, and who may need an MMR shot.
This article is for general information only and is not medical advice. Ask your doctor or pharmacist about your own vaccination needs.
Key Takeaways
- The CDC counted 4,410 confirmed U.S. measles cases in 2026 as of October 15, almost double 2025’s full-year total of 2,289.
- Pennsylvania is the epicenter, with 1,222 cases, 225 hospitalizations and five confirmed measles-associated deaths as of October 14. A sixth death is under investigation.
- The CDC is sending a “disease detective” from its Epidemic Intelligence Service to Pennsylvania, plus nearly $4 million for the response.
- About 96% of 2026 cases are in people who are unvaccinated or whose vaccination status is unknown.
- Most people with two documented MMR doses do not need another. Some adults with one dose may need a second.
How Many Measles Cases Are There in the US?
As of October 15, 2026, the Centers for Disease Control and Prevention reported 4,410 confirmed measles cases this year. Of those, 4,392 were reported by 47 jurisdictions, and 18 were among international visitors.
- 42 new outbreaks have been reported in 2026, and 96% of cases are outbreak-associated (CDC).
- The 2026 total is nearly double 2025’s 2,289 cases, and far above 2024’s 285 (CDC).
- It is the highest count since 1991, MPR News reported, citing CDC data.
- About 2% of cases had one MMR dose and 2% had two doses, ABC News reported from CDC data.
The CDC lists two confirmed measles deaths for 2026 and says that number is subject to change while reviews are completed. State and local officials have reported more deaths, which explains why counts differ between sources.
Pennsylvania: The Worst Measles Outbreak in 30 Years
Pennsylvania’s Department of Health said on October 14 that 1,222 cases had been confirmed across 42 counties this year, with 225 hospitalizations. NBC News called it the nation’s worst measles outbreak in 30 years. The outbreak, which began in late April, is centered in Lancaster County but has spread across the state.
- Deaths: the state has confirmed five measles-associated deaths and is investigating a reported death in Franklin County. NBC News, citing health officials and county coroners, counts six deaths since August.
- Two of the people who died were infants too young to get the MMR vaccine, MPR News reported.
- Only four Pennsylvania cases, less than 1%, were in vaccinated people, the state said.
- Demand for shots is up: providers gave more than 56,000 MMR doses in September, compared with about 25,000 in a typical month.
Why the CDC is sending a disease detective
Pennsylvania formally requested help through the CDC’s Epi-Aid program, a CDC spokesperson told ABC News. The agency is sending a scientist from its Epidemic Intelligence Service and releasing nearly $4 million for the response, NBC News reported. Such deployments usually last one to three weeks.
The move follows a public feud between Health Secretary Robert F. Kennedy Jr. and Gov. Josh Shapiro. On Thursday, Kennedy said Pennsylvania officials had earlier “told us that they didn’t want help,” ABC News reported. He added: “Now they’ve asked us to come in and help them, and we’re gonna do that.” Kennedy blamed the outbreak on people who “went unvaccinated during the COVID pandemic”. The Pennsylvania Department of Health did not immediately respond to ABC’s request for comment on his remarks.
Where Else Is Measles Spreading?
- Utah: 724 cases since an outbreak began in June 2025, with spread in almost every county, ABC News reported, citing state data.
- Wisconsin: cases jumped from 166 to 267 in the past month, MPR News reported.
- Minnesota: 25 cases since mid-September in two unrelated clusters, in Todd and Fillmore counties, all in unvaccinated people (Minnesota Department of Health, via MPR News).
- Earlier large outbreaks in Texas and South Carolina were largely contained to one region, ABC News said.
One reason measles keeps finding openings: MMR coverage among kindergartners fell from 95.2% in the 2019-20 school year to 92.4% in 2025-26, the CDC says. That leaves about 280,000 kindergartners at risk. The CDC says more than 95% coverage is needed for community protection.
Who Needs an MMR Booster?
The CDC talks about an “additional dose” rather than a booster. The real question is whether you have had the recommended number of doses. The CDC’s guidance in brief:
- Children: two doses, at 12-15 months and at 4-6 years.
- Most adults: at least one documented dose, unless they have other evidence of immunity.
- Adults who should have two doses: college students, healthcare workers, international travelers, close contacts of people with weakened immune systems, and adults with HIV who are not severely immunocompromised.
- People vaccinated before 1968 with an inactivated (killed) vaccine or an unknown type should get at least one dose of today’s live vaccine.
- Infants 6-11 months old who are traveling abroad should get an early dose, then two more after their first birthday.
- During an outbreak, public health officials may recommend an extra dose for people with one documented dose.
People with two documented MMR doses do not need another, Pennsylvania health officials say. Two doses are 97% effective against measles, and one dose is 93% effective, according to the CDC. Adults born before 1957 are generally presumed immune. If you cannot find your records, the CDC says there is no harm in getting another dose.
Pregnant people should wait until after pregnancy, and people with weakened immune systems should check with a doctor first. If you think you were exposed and have symptoms, contact your health care provider. Pennsylvanians can also call 877-PA-HEALTH (877-724-3258).
Frequently Asked Questions
How many measles cases are in the US in 2026?
The CDC reported 4,410 confirmed cases as of October 15, 2026, from 47 jurisdictions plus 18 international visitors.
Which state has the most measles cases?
Pennsylvania, with 1,222 confirmed cases in 42 counties as of October 14, centered in Lancaster County.
How many people have died of measles in 2026?
Counts differ. The CDC lists two confirmed deaths nationally; Pennsylvania has confirmed five and is investigating a sixth.
Do adults need an MMR booster?
Most adults with two documented doses do not. Some adults, such as travelers, healthcare workers and college students, should have two doses.
What are the first symptoms of measles?
Fever, cough, runny nose and red, watery eyes come first. A rash starting on the head follows a few days later, according to Pennsylvania health officials.
Sources
- ABC News – More than 4,400 measles cases reported in US as CDC plans to send ‘disease detective’ to Pennsylvania
- NBC News – CDC sending a ‘disease detective’ to help stop measles outbreak in Pennsylvania
- CDC – Measles Cases and Outbreaks
- CDC – Measles Vaccination
- Pennsylvania Department of Health – Statewide update, cases reach 1,222 in 42 counties
- ABC News – As measles continues to spread, health officials are seeing vaccine interest rise
- MPR News – Minnesota measles cases spike as outbreak in Todd County grows
