Measles cases hit 35-year high as vaccination rates fall below immunity threshold
Measles cases hit 35-year high amid vaccination rates falling below herd immunity protection level.
Event / Health
US Measles Outbreak 2026
Measles resurgence in the United States with emergency declarations and expanded vaccination authority, reaching nearly 3,900 cases in 2026, the worst year since 1991.
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13 articles0 articles
2026-08-02 to 2026-10-30 · UTC publication dates
Coverage begins 26 Jul, 01:53 UTC
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What happened
MMR vaccine provides 97% lifetime protection against measles
The MMR vaccine, administered over two doses, provides 97 percent lifetime protection against measles. Measles is a highly contagious viral disease that can cause fever, rash, respiratory complications, pneumonia, and brain swelling, with approximately 20 percent of identified cases resulting in hospitalization.
CDC does not include Pennsylvania measles deaths in national tally
The Centers for Disease Control and Prevention stated it does not currently include Pennsylvania's reported measles deaths in its national tally and is reevaluating how it classifies measles deaths. As of September 11, the CDC reported it has no death records from 2026 indicating measles as the underlying cause.
US records 3,294 measles cases through September 2026
The United States confirmed 3,294 measles cases through September 10, 2026, representing the worst measles year since 1991. Seven measles-associated deaths have been reported in the last two years, exceeding the combined total reported over the previous three decades.
Pennsylvania measles outbreak reaches 731 confirmed cases
Pennsylvania Department of Health reported 731 confirmed measles cases as of September 16, 2026, up 38 cases from two days prior. Lancaster County remains the worst-affected county in the state. The state also confirmed 141 hospitalized measles patients in the same update.
Pennsylvania reports fourth measles-associated death in 2026
Pennsylvania Department of Health confirmed a fourth measles-associated death in 2026, an 18-year-old from Mifflin County who died from acute disseminated encephalomyelitis, a rare neurological complication of measles. This marks four measles deaths in Pennsylvania within one month, the worst outbreak in the United States in more than three decades.
U.S. measles elimination status threatened after 26-year disease-free period
The United States had achieved local measles eradication by 2000, with most subsequent cases being travel-related until recently. After two years of continuous outbreaks beginning in 2025, measles has regained a foothold in the country following 26 years without endemic transmission.
CDC did not report measles deaths on its official tally as of mid-September
The Centers for Disease Control and Prevention had not reported any measles deaths in 2026 on its website as of Friday, September 12, 2026, stating that the National Center for Health Statistics does not currently have death records indicating measles as the underlying cause. CDC Director Dr. Erica Schwartz stated the agency had not been notified by Pennsylvania officials of the Jefferson County death.
Pennsylvania did not request CDC Epi-Aid support for measles outbreak
CDC Director Dr. Erica Schwartz stated that Pennsylvania had not requested a CDC Epi-Aid, which would deploy epidemiologists and provide on-the-ground measles outbreak support, despite repeated offers of assistance from the federal agency. By contrast, Texas, South Carolina, Virginia, Kansas, New Mexico, and Wisconsin have officially requested and worked with CDC Epi-Aids to address their measles outbreaks.
Two measles-related deaths reported in Lancaster County infants in late August
Pennsylvania Department of Health reported two measles-associated deaths in Lancaster County infants in late August 2026, the first recorded in the state in 35 years and the first reported in the U.S. that year. The first infant, a newborn, died from a ruptured spleen; the second, a six-week-old with a genetic condition called Amish lethal microcephaly, died with measles as the primary cause. Both infants were unvaccinated and not yet eligible for vaccination.
Nearly 3,300 measles cases reported across United States in 2026
The Centers for Disease Control and Prevention reported nearly 3,300 measles cases across the United States as of September 10, 2026. This represents a higher toll than 2025, which saw the most cases reported in 30 years. Thirty-eight separate outbreaks are occurring across the country, with almost all cases tied to an outbreak.
Pennsylvania reports 676 measles cases with 124 hospitalizations as of mid-September
As of September 11, 2026, Pennsylvania Department of Health confirmed 676 measles cases across 37 counties, with 124 hospitalizations. Over 100 new cases were reported in the week prior. Nearly all cases occurred in unvaccinated individuals, with only four cases (less than 1%) in vaccinated persons.
40-year-old unvaccinated woman dies from measles complications in Pennsylvania
A 40-year-old unvaccinated woman from Jefferson County, Pennsylvania died on September 12, 2026, from complications associated with measles. She had recent contact with a neighbor who had a laboratory-confirmed case of measles. The death certificate lists respiratory failure caused by suspected measles, chronic obstructive pulmonary disease, and asthma as contributing factors.
676 measles cases confirmed across 37 Pennsylvania counties
As of September 12, 2026, Pennsylvania Department of Health reported 676 confirmed measles cases across 37 of the state's 67 counties, resulting in 124 hospitalizations. Of the confirmed cases, only 4 (less than 1%) involved fully vaccinated individuals. The outbreak represents a significant surge in cases.
3,387 measles cases reported in United States in 2026
As of September 13, 2026, the Centers for Disease Control and Prevention reported 3,387 measles cases across the United States in 2026, an increase from 2,286 cases reported in 2025. This represents the largest resurgence of measles in 35 years. Pennsylvania and South Carolina account for the majority of cases (676 and 671 respectively), followed by Utah with 518 cases. Over 100 cases have also been reported in Texas, Virginia, Wisconsin, Florida, Ohio, and Arizona.
Pennsylvania reports third measles-related death in 2026
Pennsylvania has confirmed three measles-related deaths in 2026. Two deaths in August involved infants too young to be vaccinated (the first measles vaccine dose is administered around 12-15 months of age). One infant boy died with a ruptured spleen; measles was recorded as a significant condition but did not directly cause the rupture. A second infant girl, age 6 weeks, with Amish lethal microcephaly died from measles infection.
CDC disputes Pennsylvania measles death counts
The Centers for Disease Control and Prevention has not reported any measles deaths in 2026 on its website as of Friday, September 13, 2026, despite Pennsylvania officials reporting three measles-related deaths. CDC Director Dr. Erica Schwartz stated that the CDC was not notified by Pennsylvania officials of the most recent death in Jefferson County and noted that Pennsylvania has not requested CDC Epi-Aid assistance despite repeated offers of support to deploy epidemiologists for outbreak investigation.
40-year-old Pennsylvania woman dies from measles complications
A 40-year-old resident of Jefferson County, Pennsylvania died on September 12, 2026 from complications associated with measles. The woman was unvaccinated against measles. Jefferson County Coroner Greg Furlong confirmed the death, stating it serves as a reminder that measles can be serious and life-threatening for people of any age.
Measles outbreak concentrated in unvaccinated religious communities
Health Secretary Robert F. Kennedy Jr. stated that the measles outbreak has been almost entirely confined to religious communities that decline vaccination. This reflects patterns in the 2026 outbreak where vaccination rates fell below levels needed for herd immunity in specific communities.
Pennsylvania measles outbreak reaches 393 confirmed cases
Pennsylvania has confirmed 393 measles cases across 28 counties in 2026, with 86 new cases diagnosed in the week preceding August 25. Lancaster County accounts for 177 of the confirmed cases. Approximately 70 people have been hospitalized for measles complications.
MMR vaccine provides 97% protection against measles
The Centers for Disease Control and Prevention recommends two doses of the MMR (measles, mumps, rubella) vaccine: the first dose administered between 12-15 months of age, and the second between ages 4-6. Two doses provide approximately 97% lifetime protection against measles. One dose alone provides 93% effectiveness.
Read the coverage
2 alternative perspectives
States deploy targeted vaccination campaigns in high-risk communities
State health departments deploy pop-up clinics and community outreach to vaccinate vulnerable populations amid ongoing measles resurgence.
Spartanburg County measles outbreak approaches 1,000 cases as vaccination efforts intensify
South Carolina's Spartanburg County measles outbreak reaches nearly 1,000 cases; churches launch vaccination clinics.
Measles cases surge as vaccination coverage drops to 92.5%
Measles cases surge as vaccination coverage falls to 92.5% among US kindergarteners.