Measles cases nationwide topped 5,400 on Friday as the Centers for Disease Control and Prevention reported 5,412 infections across 45 states, accompanied by a rise in fatalities to 10 deaths nationwide.
Wisconsin health officials reported a second measles death on Friday while Pennsylvania health officials confirmed an additional fatality, bringing the national death toll to seven in Pennsylvania, two in Wisconsin, and one in New York, ABC News reported. The nationwide surge, which has recorded 5,412 infections across 45 states according to the CDC, marks a dramatic escalation from an annual average of 180 cases between 2000 and 2024.
The United States is currently experiencing its worst measles outbreak since 1991, with national trackers like the Johns Hopkins University International Vaccine Access Center recording more than 5,400 cases. A newsletter from the Brown University School of Public Health’s Tracking Report tallied 5,478 cases and nine deaths as of November 5, reflecting lab-confirmed figures compiled from state and county health departments, local news releases, and news articles.
“It's just like popcorn: outbreak, outbreak, outbreak, outbreak. All over the country,” epidemiologist Jennifer Nuzzo, director of Brown University's Pandemic Center, said. While the CDC reported 5,182 confirmed cases and six deaths as of November 6, other public health aggregators have recorded higher totals.
The virus is exceptionally contagious; it lives on surfaces and remains suspended in the air for two hours after an infected person leaves a room, and a single sick individual can infect up to 90% of unvaccinated contacts.
Declining MMR Vaccination Rates Impact Herd Immunity
The resurgence coincides with a decline in national immunization coverage. The proportion of kindergartners receiving the measles, mumps, and rubella (MMR) vaccine dropped from 95 percent in 2019 to 92 percent in 2026, ABC News reported. Communities typically require a 95 percent vaccination rate to sustain herd immunity, leaving roughly 300,000 kindergartners entering classrooms unvaccinated this year.
The MMR vaccine requires two doses, with the first administered between 12 and 15 months of age and the second between ages 4 and 6. Two doses are 97 percent effective at preventing infection, and vaccinated individuals who contract the virus experience less severe illness, ABC News reported.
Medical complications from the virus affect a substantial share of pediatric patients. One in 10 children who contract measles develop ear infections, another one in 10 experience diarrhea, and one in 20 develop pneumonia, ABC News reported.
One in 1,000 children develop encephalitis, a brain swelling that can lead to seizures, deafness, or intellectual disability, while one to three of every 1,000 infected children die from respiratory and neurological complications. Globally, the World Health Organization estimates there are about 95,000 measles deaths annually, primarily among unvaccinated children under the age of five.
Experts Evaluate US Measles Elimination Status
International health experts meeting in Washington, D.C., through Friday are evaluating whether the United States has maintained endemic transmission for more than 12 months, a review that could strip the nation of its official measles elimination status held since 2000, CIDRAP reported.
The Pan American Health Organization commission evaluates epidemiological data, vaccination coverage, healthcare system monitoring, and outbreak response speeds to determine whether infections stem from separate travel-related introductions or sustained domestic circulation of the same viral strain.
“Loss of measles elimination status in the US signals to the world that we are not up to this task and may diminish their own aspirations to achieve and sustain measles elimination,” William Moss, MD, MPH, an infectious disease epidemiologist at Johns Hopkins Bloomberg School of Public Health, said.
The prolonged outbreaks also carry a massive financial burden. A tool developed by Johns Hopkins University researchers estimates the economic cost of the 2026 outbreaks at nearly $83 million, encompassing $56 million in public health response costs, almost $25 million in lost productivity, and more than $1.8 million in direct medical expenses, CNBC reported. That follows 2025 outbreaks involving 2,289 confirmed cases nationwide that carried an economic cost exceeding $37 million.
Public health departments must divert substantial staffing and resources to investigate infections, notify exposed individuals, and coordinate with schools and hospitals during active outbreaks. “It’s not like your health department is sitting around waiting for measles outbreaks,” said Mattingly. “They’re working, doing all these other things, and imagine having to just drop what you’re doing because there’s been a huge outbreak in the community,” Mattingly told CNBC.
Earlier coverage: U.S. Measles Cases Surpass 5,000 as Elimination Status Review Looms
