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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2026-08-02 to 2026-10-30 · UTC publication dates
Coverage begins 26 Jul, 01:53 UTC
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What happened
New York administers over 1,000 MMR vaccine doses in rural areas since July
Since July 15, 2026, local health departments in New York have administered more than 1,000 measles-mumps-rubella (MMR) vaccine doses in rural areas across 18 counties affected by the outbreak.
Pennsylvania reports over 1,000 measles cases, largest outbreak in over 30 years
Pennsylvania health officials reported on October 2 that the state has more than 1,000 measles cases, making it the largest state outbreak in more than three decades. The state has recorded five measles-related deaths. Most cases are concentrated in rural counties, particularly those bordering New York.
New York reports 108 measles cases as of October 3, 2026
New York State has reported 108 measles cases through October 3, 2026, including 92 cases since July 15 in under-immunized rural communities across 18 counties. Seven cases are in New York City and 101 are elsewhere in the state. These numbers are well above typical annual levels.
New York Governor declares statewide disaster emergency due to measles outbreak
New York Governor Kathy Hochul issued an executive order on October 5, 2026, declaring a statewide disaster emergency in response to a measles outbreak. The declaration was the first such emergency declaration by a U.S. state since measles cases began surging in 2025. The emergency enables the state to respond more quickly to the outbreak and allows healthcare professionals to take additional measures to facilitate vaccination and testing.
Nearly 20 percent of measles cases result in hospitalization in the United States
According to public health data, nearly 20 percent of individuals who contract measles in the United States are hospitalized. Of the approximately 3,900 measles cases reported nationally in 2026, 352 cases or nine percent had been hospitalized according to CDC data as of October 1.
Low vaccination coverage in rural communities enables measles spread
Rural communities in New York and Pennsylvania have vaccination coverage rates below 95 percent, enabling rapid measles transmission. Lancaster County, Pennsylvania reports only 87 percent vaccination coverage among entering kindergarten students. Low vaccination rates in these communities allow each measles case to spread to 12 to 18 susceptible people.
Dispute over measles death classifications between Pennsylvania and federal officials
A disagreement exists between Pennsylvania Governor Josh Shapiro and federal Health and Human Services Secretary Robert F. Kennedy, Jr. over how measles-related deaths should be classified. Shapiro counts deaths as measles-associated when laboratory or epidemiological evidence shows measles was present and potentially contributing, while Kennedy insists on the stricter federal NCHS death-certificate standard counting measles only when it is the underlying cause of death. Pennsylvania reports five deaths while federal figures report two.
New York expands healthcare professionals authorized to administer measles vaccines
New York Governor Hochul's executive order expands the group of healthcare professionals authorized to administer measles-mumps-rubella (MMR) vaccines. The expanded pool now includes registered nurses who can order tests for suspected measles, pharmacists authorized to vaccinate children as young as two, paramedics, advanced EMS providers, and midwives.
United States reports nearly 3,900 measles cases in 2026, worst year since 1991
The United States has reported nearly 3,900 measles cases in 2026 according to the Centers for Disease Control and Prevention, marking the worst year for measles since 1991. The CDC also reported two deaths, though Pennsylvania officials dispute this count and report five deaths in that state alone. The national outbreak includes major surges in Pennsylvania, South Carolina with 670 cases, and Utah with 535 cases.
New York requires MMR vaccination reporting within 72 hours
New York's emergency order requires all measles-mumps-rubella (MMR) vaccinations to be reported to state or New York City immunization registries within 72 hours. The order waives adults' consent for such reporting, though vaccination itself still requires patient or legal guardian consent.
Pennsylvania reports 198 hospitalizations and severe complications from measles
Of 1,004 measles cases in Pennsylvania, 198 people have been hospitalized. Among pediatric cases, approximately 18% required hospitalization. Doctors are observing severe complications including dehydration, hepatitis, severe and irreversible neurological damage from brain inflammation (encephalitis), and secondary bacterial infections. Some children have experienced encephalitis severe enough to cause disorientation and inability to recognize family members.
CDC stands ready to deploy epidemiologists to Pennsylvania if Epi-Aid request received
The Centers for Disease Control and Prevention stated it has not received a formal Epi-Aid request from Pennsylvania as of October 6, 2026, but indicated it stands ready to deploy epidemiologists to support the state's identified needs if requested. An Epi-Aid is a rapid, short-term field investigation of an urgent public health problem that provides resources including workforce expansion and epidemiologic capacity building. The CDC has previously deployed Epi-Aids to Texas, South Carolina, Virginia, Kansas, New Mexico, and Wisconsin.
International health officials to assess U.S. and Mexico measles-free status in November 2026
International health officials are scheduled to meet in November 2026 to determine whether the United States and Mexico have lost their measles-free status. This assessment comes in response to the significant resurgence of measles cases across North America in 2026.
Lancaster County Amish community experiences measles outbreak linked to low vaccination rates
Lancaster County, Pennsylvania, home to approximately 44,000 members of the nation's largest Amish population, is the epicenter of the state's measles outbreak with 391 confirmed cases. While nothing in Amish religion is inherently anti-vaccine, historical vaccination rates in Amish communities have been lower than those of the general population. Infectious disease experts note that similar outbreaks could occur in any county with a large percentage of unvaccinated people if measles spreads into those communities.
United States measles cases exceed 3,800 in 2026, highest total since 1991
The United States has reported more than 3,800 measles cases in 2026 across 45 states and Washington, D.C., marking the highest annual total since 1991. The nation experienced eight measles-associated deaths in the past two years, more than the combined total of reported deaths over the previous three decades. This represents a significant resurgence after measles elimination was declared in the U.S. in 2000.
Pennsylvania measles cases surpass 1,000 in 2026, largest state outbreak in over 30 years
Pennsylvania reported 1,004 measles cases across 39 counties as of October 6, 2026, making it the largest measles outbreak in any U.S. state in more than three decades. The outbreak began in late April 2026 west of Philadelphia and shows no signs of slowing. Lancaster County, home to the nation's largest Amish population, is the epicenter with 391 cases. Fewer than 1% of cases occurred among fully vaccinated individuals.
Pennsylvania Department of Health administers 8,800 MMR vaccine doses in outbreak response
The Pennsylvania Department of Health administered more than 8,800 MMR vaccine doses in response to the measles outbreak, with approximately 3,500 administered in August 2026 and more than 2,500 in September 2026. This response is substantially lower than South Carolina's vaccination surge, which administered nearly 15,000 doses during its outbreak.
Five measles-associated deaths reported in Pennsylvania outbreak
Five deaths have been associated with Pennsylvania's measles outbreak. Two deaths occurred among unvaccinated adults: an 18-year-old and a 40-year-old woman with a history of asthma. Two deaths occurred among infants too young to receive the MMR vaccine, including a newborn whose mother went into premature labor. A fifth death involved an unvaccinated Lancaster County resident of unknown age. The CDC acknowledged only two deaths on its dashboard initially before updating to include additional deaths.
MMR vaccination rates decline below herd immunity threshold in U.S. schools
During the 2025-2026 school year, 92.4% of kindergartners received the MMR vaccine, down from 95.2% in the 2019-2020 school year before the COVID-19 pandemic. The 95% vaccination rate is the accepted threshold needed for herd immunity to prevent measles outbreaks. Vaccination rates have declined due to parental waivers, healthcare access issues, and misinformation.
South Carolina measles outbreak contained to 997 cases within six months
South Carolina's measles outbreak, which was previously the largest in approximately 30 years, was contained to 997 cases and ended by April 2026. The outbreak was linked to a community of people who emigrated from Ukraine over the past few decades. State health officials credited a massive vaccination surge of nearly 15,000 MMR doses, representing an 82% increase compared to the previous year, with successfully halting the outbreak in the northwestern region where it was centered.
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.