The U.S. is grappling with its worst resurgence of measles in decades, with more than 4,580 cases recorded so far in 2026, more than double the number for all of 2025, according to new data from the Centers for Disease Control and Prevention. Pennsylvania is the hardest hit state, with at least 1,338 confirmed cases across 44 counties, more than 250 hospitalizations and five deaths.
New data from the CDC shows more than 4,580 measles cases across the U.S. so far in 2026, more than double the number for the whole of 2025. The vaccination status of 96% of those who contracted measles in 2026 was "Unvaccinated or Unknown," according to the CDC.
Pennsylvania's outbreak has grown to at least 1,338 confirmed cases across 44 counties, the Pennsylvania Department of Health said on Friday, with 21 new cases as of Oct. 21. More than 250 people have been hospitalized and five people have died; three of the dead lived in Lancaster County. In Lancaster and Mifflin counties, two of the hardest hit, local Amish communities, which have low vaccination rates, are being affected the most.
On Thursday, Secretary of Health Dr. Debra Bogen held a roundtable with Mifflin County healthcare providers to assess their needs in combatting the disease. "Our state metrics and data tell part of the story of the measles outbreak in Pennsylvania, but listening to the people on the ground caring for people in affected communities like Mifflin County is essential to refining our public health response," Bogen said in a statement.
Health officials say one of the best ways to protect against measles is vaccination. Two doses of the measles, mumps, and rubella (MMR) vaccine are nearly 97% effective against measles, and one dose is about 93% effective, according to the CDC. The Pennsylvania health department said healthcare providers have seen more residents interested in getting vaccinated, with more than 39,000 measles vaccines administered during the first three weeks of October, higher than the average of 25,000 vaccines administered in a month.
Elsewhere, New York Gov. Kathy Hochul declared a disaster emergency earlier this month after rising measles cases; the state has recorded more than 160 confirmed cases, according to Oct. 20 data from the New York State Department of Health. Utah has reported more than 700 cases this year, with no new diagnoses in three weeks. South Carolina, which dealt with an outbreak earlier this year, has recorded at least 997 cases in 2026, though its outbreak ended in April.
Analysis
Why This Matters
- Measles is highly contagious, and a return of thousands of cases, with deaths and hundreds of hospitalizations, marks a significant reversal after decades of near-elimination.
- The outbreak is concentrated in communities with low vaccination coverage: 96% of cases in 2026 were among people who were unvaccinated or of unknown status.
- The response is now a live test of public health practice: Pennsylvania reported more than 39,000 measles vaccinations in the first three weeks of October, a sign that concern is translating into action.
Background
Measles was declared eliminated in the United States more than two decades ago, but the disease can reappear when vaccination coverage falls, and imported cases can spark local outbreaks. The MMR vaccine has long been the standard protection, with two doses offering near-complete immunity. The current wave spans several states, with Pennsylvania the hardest hit and smaller outbreaks in New York, Utah and South Carolina.
What to Watch
- Whether Pennsylvania's case count keeps climbing: 21 new cases were reported as of Oct. 21.
- Whether the October surge in vaccinations in Pennsylvania slows transmission in the Amish communities of Lancaster and Mifflin counties.
- How other states respond: Utah has gone three weeks without a new diagnosis and South Carolina's outbreak has ended, while New York has declared a disaster emergency.
Checked
12 claims in this story checked against 1 source: 10 supported.
Show each claim
- SupportedU.S. measles cases have more than doubled last year’s total.OPB: “there have been more than 4,580 measles cases across the U.S. since Oct. 22, which is more than double the number for the whole of 2025.”
- SupportedThe Pennsylvania measles outbreak is spreading.OPB: “U.S. measles cases more than double what they were last year as outbreak spreads.”
- SupportedPennsylvania has at least 1,338 confirmed cases across 44 counties this year.OPB: “At least 1,338 cases of measles have been confirmed in 44 counties across the state so far this year”
- SupportedMore than 250 people have been hospitalized in Pennsylvania.OPB: “More than 250 people have been hospitalized and 5 people have died”
- SupportedFive people have died in Pennsylvania.OPB: “More than 250 people have been hospitalized and 5 people have died, the department also said.”
- SupportedThe U.S. is experiencing its worst measles resurgence in decades.OPB: “The U.S. is grappling with its worst resurgence of measles in decades”
- Partly supportedThe U.S. has had more than 4,580 measles cases so far in 2026.OPB: “there have been more than 4,580 measles cases across the U.S. since Oct. 22”
- Partly supportedPennsylvania is the hardest-hit state.OPB: “cases particularly high in the state of Pennsylvania.”
- SupportedThe vaccination status of 96% of people who contracted measles in 2026 was “Unvaccinated or Unknown.”OPB: “The vaccination status of 96% of those who contracted measles in 2026 was “Unvaccinated or Unknown,” according to data from the CDC.”
- SupportedLocal Amish communities in Lancaster and Mifflin counties, which have low vaccination rates, are being affected the most.OPB: “In Lancaster and Mifflin counties, two of the counties with the highest number of cases, local Amish communities, which have low vaccination rates, are being impacted the most.”
- SupportedDr. Debra Bogen said: “Our state metrics and data tell part of the story of the measles outbreak in Pennsylvania, but listening to the people on the ground caring for people in affected communities like Mifflin County is essential to refining our public health response,”OPB: ““Our state metrics and data tell part of the story of the measles outbreak in Pennsylvania, but listening to the people on the ground caring for people in affected communities like Mifflin County is essential to refining our public health response,” Bogen said in a statement.”
- SupportedMore than 39,000 measles vaccines were administered in Pennsylvania during the first three weeks of October, above the average of 25,000 in a month.OPB: “more than 39,000 measles vaccines were administered during the first three weeks of October – higher than an average of 25,000 vaccines administered across the state in one month”
