Measles infections surpassed 1,000 reported cases in one state this week as the United States continues to hurdle past a 30-year case high.
Pennsylvania, the current center of the nation's largest outbreak, reported 1,004 total cases on Oct. 5, a remarkable uptick from just 106 total cases last year. A handful of other states are also contending with clusters of 100 or more infections
Plummeting vaccination rates and the resulting resurgence in cases have put the United States at risk of losing its measles elimination status. Defined by the World Health Organization (WHO) as freedom from the continuous spread of a disease for at least a year, reaching elimination status has been called a "historic public health achievement" by the CDC – but the global
health organization is set to review it next month after 2025's Texas outbreak that killed three.
See where cases are growing and where the most people are sick.
See map of states with most measles cases
As of Oct. 1, the CDC reported 3,887 confirmed measles cases in 45 states plus Washington, DC.
The actual number 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. Plus, the CDC's counts tend to lag behind states because its figures are only updated weekly after certain reporting parameters are met.
As of Oct. 5, Pennsylvania has the largest measles outbreak, with infections surpassing 1,004, according to state health data.
The state has also reported five "measles-associated" deaths; however, the CDC count still only reflects two after a terse back-and-forth between Secretary of Health and Human Services Robert F. Kennedy Jr. 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, including Utah and South Carolina, are contending with outbreaks of 500 or more cases. New York declared a state of emergency on Oct. 5 after the state surpassed 100 cases.
Measles cases hit multi-decade high
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. 1, the CDC reported 3,887 confirmed cases, well surpassing last year's total with three months still left in the year.
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.
About 90% of unvaccinated people who are exposed to measles end up contracting it. Additionally, 1 in 5 of those people end up hospitalized, according to the CDC. It is especially dangerous for young children.
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 to 15 months for the first dose and ages 4 to 6 years 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.
This article originally appeared on USA TODAY: A highly infectious disease is spreading. See in which US states
