Measles cases in the United States have nearly doubled last year’s already decades-high total as states continue to battle growing outbreaks.
The Centers for Disease Control and Prevention reported more than 4,400 confirmed measles cases nationwide as of Oct. 15. Pennsylvania, now the epicenter of the nation’s largest outbreak, surpassed 1,000 cases in early October, a dramatic increase from the 106 cases reported statewide last year. Several other states are also reporting sizable outbreaks, with more than 100 infections each.
The CDC said Oct. 13 that it would deploy more support to Pennsylvania to help investigate the outbreak following a feud between Health and Human Services Secretary Robert F. Kennedy Jr. and the state's governor over how
measles-associated deaths should be defined and counted. The agency said it would work with local health officials to investigate the outbreak, strengthen response efforts and prevent spread.
Reuters previously reported in September that Pennsylvania's health department sought emergency support from the CDC, but only on the condition that it acknowledge the measles-associated deaths reported by the state. Additional states, including Texas, South Carolina, Virginia, Kansas, New Mexico and Wisconsin, are also working with the CDC's Epi-Aid emergency response program, the agency said.
Falling vaccination rates and the resulting resurgence of measles have raised concerns that the United States could lose its measles elimination status. The designation, awarded when a disease is no longer spreading continuously within a country for at least 12 months, has been described by the CDC as a historic public health achievement. The World Health Organization is expected to review the U.S. status next month following the 2025 Texas outbreak that killed three people.
See where cases are rising and which parts of the country are reporting the highest totals.
Measles cases nearly double last year's total
As of Oct. 15, the CDC reported 4,410 confirmed measles cases in 45 states plus Washington, DC. Of those, 451 (10%) were hospitalized. The majority of cases (42%) were in children and teenagers ages 5 to 19, which is typical of past outbreaks. People aged 20 and older were the second largest group with close to 41% of cases, a significant increase compared with last year's 29%.
Measles is a highly contagious, vaccine-preventable disease caused by a virus that primarily and most severely afflicts children. The virus is one of the most contagious infectious diseases — so contagious that 90% of unvaccinated people who are exposed to it contract the disease. Additionally, 1 in 5 of those people end up hospitalized, according to the CDC.
Almost all illnesses, 96%, reported in the current outbreaks were in people who were unvaccinated or had unknown vaccination status.
The actual number of sick people is likely higher, as only cases confirmed by doctors and reported to the CDC are counted. This means people who get sick but don't see a doctor for a diagnosis are not included. The CDC's counts also tend to lag behind states because its figures are only updated weekly after certain reporting parameters are met.
See states with most measles cases
As of Oct. 14, Pennsylvania has the largest measles outbreak, with infections surpassing 1,200, according to state health data.
The state has also reported five measles-associated deaths. However, the CDC count still reflects only two after a terse back-and-forth between Kennedy and Pennsylvania Gov. Josh Shapiro. In social media posts and speeches, Kennedy accused Shapiro of "fabricating" the deaths, while Shapiro said Kennedy was "downplaying the severity of measles."
Other states, Utah and South Carolina, are contending with outbreaks of 500 or more cases. New York declared a state of emergency Oct. 5 after the state surpassed 100 cases.
Measles cases reach highest point in decades
Measles, one of the most contagious infectious diseases, was eliminated from the United States in 2000, something the CDC called a "historic public health achievement."
Cases have since hit their highest level in more than three decades under the Trump administration, which has attempted to change the childhood vaccine schedule. Officials have also promoted the idea that vaccines, including the combined measles, mumps and rubella (MMR) shot, are more dangerous than the diseases they prevent, despite decades of scientific evidence saying otherwise.
As of Oct. 15, the CDC's 4,410 confirmed case count was nearly double last year's total with two months remaining in 2026.
Cases previously reached a 30-year high in 2025, with 2,289 confirmed infections across 43 states plus Washington, DC, for the entire year. The majority, 93%, of infections were contracted by unvaccinated people or those with unknown vaccination statuses. Three people, including two children, died as a result of the outbreaks, marking the first pediatric deaths from measles in a decade.
The MMR vaccine (measles, mumps and rubella), which protects against measles with 97% efficacy, is typically administered to children as part of the regular vaccine course at ages 12-15 months for the first dose and ages 4 to 6 for the second. MMR vaccination uptake has declined in recent years, resulting in a growing number of states no longer reporting rates consistent with herd immunity.
Contributing: Reuters
This article originally appeared on USA TODAY: Measles cases nearly double last year's high. See where cases are up
