How bad is the measles outbreak in the United States?
The United States declared measles eliminated in 2000. In 2026 it has recorded more cases than in any year since 1991, and officials in the hardest-hit state say even that count is too low. The federal government and Pennsylvania also disagree on how many people have died.
THE SHORT ANSWER
It is the worst measles year in the US in decades. The Centers for Disease Control and Prevention (CDC), the federal public-health agency, counted 4,410 cases as of Oct. 15, the most since 1991 and nearly twice the 2,289 reported in all of 2025. Pennsylvania accounts for more than a quarter of cases and reports six deaths, though the CDC lists only two. About 96% of cases are in people who are unvaccinated or whose status is unknown, and experts think the true total is higher.
What happened
On Oct. 12, the Franklin County Coroner's Office in Pennsylvania announced that a 39-year-old woman died on Oct. 10 in Chambersburg. She had several underlying conditions and a recent measles diagnosis. A coroner's spokesperson said she had not been vaccinated and that the primary cause of death was "a probable acute cardiac event due to possible complications of the measles." It is the state's sixth measles-associated death this year. The Pennsylvania Department of Health said it was conducting a thorough review of the death.
On Oct. 16, the CDC reported 4,410 confirmed cases nationwide as of Oct. 15, up 330 in a week, with 451 hospitalisations. Pennsylvania reported 1,222 cases across 42 counties as of Wednesday, with 225 hospitalisations, five confirmed deaths and a sixth under investigation. After Pennsylvania formally asked for help through the CDC's Epi-Aid program, the agency said it would send an investigator from its Epidemic Intelligence Service, a corps of field "disease detectives."
State health centre staff have given more than 5,900 doses of the measles, mumps and rubella (MMR) vaccine at 202 pop-up clinics. Health and Human Services Secretary Robert F. Kennedy Jr. told Spectrum News 1 that he would bring the Pennsylvania outbreak "to a quick close." The CDC, meanwhile, still acknowledges only two measles deaths nationwide this year.
Why it matters
Measles spreads through the air and can seriously harm children, pregnant women and adults, and it is the most contagious of the common vaccine-preventable diseases. The 2026 total is already close to twice last year's, and vaccination among kindergarteners has slipped from 95.2 percent in 2019-2020 to 92.4 percent in 2025-2026. The CDC estimates that about 280,000 kindergarteners are at risk because of those gaps. Pennsylvania's six deaths in about 1,200 cases are more than experts would expect, which suggests many mild cases are going uncounted. Dr. Paul Offit, a pediatrician at Children's Hospital of Philadelphia, thinks the state is "probably closer to 6,000 cases." The official toll may therefore understate the outbreak it is meant to measure.
- For unvaccinated families, Nearly all cases are in people without the vaccine or with unknown status. Children aged five to 19 make up 42 percent of cases, adults 41 percent and children under five 17 percent.
- For state and local health departments, Pennsylvania has asked for federal help and is running pop-up clinics, while New York has declared a statewide disaster emergency to widen who can give vaccines.
- For Amish and Mennonite communities, Lancaster County, the centre of Pennsylvania's outbreak, is home to the state's largest Amish community. Parents in such traditional communities often care for sick children at home, so cases may never reach health officials.
- For anyone following the numbers, The gap between the state's six deaths and the CDC's two means the federal figure alone does not show how deadly the outbreak has been.
The background: a disease eliminated, then slipping coverage
Before and after the vaccine
Before the measles vaccine arrived in 1963, the CDC estimated that three to four million Americans caught measles each year. About 500,000 of those cases were reported, 48,000 people were hospitalised and 400 to 500 died. A combined MMR vaccine, which protects against measles, mumps and rubella, was licensed in the US in 1971. A second dose was recommended in 1989.
Cases fell sharply with vaccination, but an outbreak of almost 30,000 cases in 1990 led to a renewed push and the second dose becoming part of the recommended schedule. Fewer than 200 cases were reported in the US each year from 1997 to 2013. The country declared measles eliminated in 2000.
Doubt and weaker rules
In 1998, Andrew Wakefield published a fraudulent paper that claimed a link between the MMR vaccine and autism. The paper was later retracted, and multiple studies have found no such link. In the UK, MMR uptake fell from 92% before the paper to below 80% after it.
In the US, the 2014 Disneyland measles outbreak and low vaccination in pockets of California led that state to remove personal and religious exemptions in 2015. More recently, some states have moved the other way. In April 2025, Idaho became the first state to remove most of its immunization requirements, including for schools. The reference material notes that falling vaccination rates have contributed to measles returning.
Texas, 2025
The current wave began in January 2025 in Texas, where Gaines County became the epicentre. The outbreak spread to New Mexico, Oklahoma, Kansas and the Mexican state of Chihuahua, and it was concentrated in unvaccinated Mennonite communities. It infected hundreds of people and killed three, two children in Lubbock and an adult in Lea County, New Mexico. All three were unvaccinated. Texas declared the outbreak over on Aug. 18, 2025.
Across all of 2025, the CDC reported 2,289 cases. For comparison, the CDC confirmed 285 cases in 2024.
A bigger year in 2026
Cases kept coming as 2026 began. In January, North Carolina counted 310 cases by Jan. 12 and South Carolina 434 by Jan. 15, and the CDC reported 416 new cases across 14 states that month. On Jan. 5, Kennedy announced cuts to the CDC childhood vaccine schedule, dropping the recommendation that all children get vaccines for rotavirus, influenza, RSV, meningococcal disease, hepatitis A and hepatitis B. On Aug. 10, President Donald Trump signed an executive order requiring the MMR vaccine to be split into three separate shots. He said the recommendation had to do with many subjects, "autism in particular."
Pennsylvania's outbreak began in February with five cases in Lancaster County. By late August it had produced the state's first two measles deaths, both infants in Lancaster County, and the first measles deaths of the year in the US.
The last few weeks
In September, Pennsylvania reported two more deaths, an 18-year-old in Mifflin County and a 40-year-old woman in Jefferson County. On Sept. 30 it announced a fifth, an unvaccinated Lancaster County resident. In early September, the CDC said it would count a measles death only when the National Center for Health Statistics lists measles as the underlying cause. On Sept. 29, the CDC confirmed its second death. New York Governor Kathy Hochul declared a statewide disaster emergency on Oct. 5. The Franklin County death followed on Oct. 10, and the CDC's case count reached 4,410 by Oct. 15.
GOOD TO KNOW
Historically, measles kills 1 to 2 people per 1,000 cases. Six deaths among Pennsylvania's 1,136 confirmed cases as of Oct. 9 works out to about five per 1,000, by our own arithmetic, which is why experts think the real outbreak is much larger.
Why does the CDC count two deaths when Pennsylvania counts six?
The two use different rules. Pennsylvania calls a death measles-associated if it happens within 30 days of the start of symptoms, with clinical evidence of measles, a positive lab test and no unrelated cause of death. The state also considers medical records and exposure to measles.
In early September, the CDC said it would count a death only when the National Center for Health Statistics, which compiles death records, lists measles as the underlying cause. Those records can take weeks to arrive. The CDC's death count has not been updated since late September, and a note on its page says the total may change as reviews are completed. The agency is working with the Council of State and Territorial Epidemiologists to build a standard case definition for measles deaths, and a spokesperson for that group expects the work to take two to three months.
The Franklin County woman's cause of death was recorded as a probable cardiac event due to possible complications of measles. That wording shows how a measles death can be recorded under a cardiac cause. The reports so far do not say how the federal count will treat it.
Why does vaccination coverage matter so much for measles?
Measles is so contagious that more than 95% of a population must be vaccinated to protect the minority who are not immune. The virus can stay in the air for up to two hours after an infected person coughs, sneezes or talks. Unvaccinated people exposed to it face a 90% risk of infection, according to the CDC estimate cited in the reference material.
Two doses of the MMR vaccine protect 97% of people against measles. The CDC recommends the first dose at 12 to 15 months and the second before kindergarten. National kindergarten coverage of 92.4 percent is below the 95% threshold, which means measles can find clusters of unprotected people. In the current outbreak, only 2% of cases are in people who had one dose and 2% in people who had two.
Timeline: 1963 to today
VACCINE AND ELIMINATION
The measles vaccine is introduced in the US; before it, the CDC estimated three to four million infections a year.
The combined MMR vaccine is licensed for use in the US.
A second dose of the vaccine is recommended.
An outbreak of almost 30,000 cases leads to a renewed push for vaccination.
Andrew Wakefield publishes a fraudulent paper falsely linking MMR to autism.
The US declares measles eliminated.
SLIPPING RULES AND THE TEXAS OUTBREAK
California removes personal and religious vaccine exemptions after the 2014 Disneyland outbreak.
A measles outbreak begins in Texas, centred on Gaines County.
An unvaccinated adult dies in Lea County, New Mexico, linked to the outbreak.
Idaho removes most of its immunization requirements, including for schools.
Texas declares its outbreak over after three deaths.
THE 2026 SURGE
North Carolina and South Carolina report hundreds of cases, and the CDC counts 416 new cases across 14 states.
Pennsylvania's outbreak begins with five cases in Lancaster County.
Pennsylvania reports its first two measles deaths, both infants, the first of the year in the US.
President Trump signs an order requiring the MMR vaccine to be split into three separate shots.
The CDC says it will count a measles death only when national death records list measles as the underlying cause.
Pennsylvania reports the deaths of an 18-year-old in Mifflin County and a 40-year-old woman in Jefferson County.
The CDC confirms its second measles death as US cases hit a 35-year high.
Pennsylvania announces its fifth death, an unvaccinated Lancaster County resident.
THE PAST TWO WEEKS
New York Governor Kathy Hochul declares a statewide disaster emergency over measles.
Pennsylvania reports a sixth death, a 39-year-old unvaccinated woman, as the CDC counts 4,080 cases nationally.
The CDC reports 4,410 cases and says it is sending an investigator to Pennsylvania.
What to watch next
- Pennsylvania's review of the Franklin County death. The state Health Department says it will update the public after its investigation is finished, which will show whether its toll stays at six.
- The CDC's death definition. The agency is working with the Council of State and Territorial Epidemiologists on a standard definition, which that group expects to take two to three months.
- New York's emergency order. The order, which widens who can give vaccines and order measles tests, runs until Nov. 4.
- The weekly CDC count. The national total rose by 330 in the past week, and the next updates will show whether that pace continues.
Sources
- CIDRAP16 OCT 2026
- The Detroit News16 OCT 2026
- Al Jazeera16 OCT 2026
- ABC News16 OCT 2026
- FOX 29 Philadelphia12 OCT 2026
- NBC News12 OCT 2026
- The Independent12 OCT 2026
- Straight Arrow12 OCT 2026
- Yahoo News12 OCT 2026
How this article was made: Implica's editorial system wrote it from the news reports above, with the background drawn from Wikipedia: Measles, MMR vaccine, Vaccination policy of the United States, 2025 Southwest United States measles outbreak.