CIDRAP-US measles cases grow by 8% in 1 week for a total of 4,410 cases

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US measles cases grow by 8% in 1 week for a total of 4,410 cases

www.cidrap.umn.edu

US measles cases grow by 8% in 1 week for a total of 4,410 cases​

Liz Szabo, MA

Chris Dall, MA

Today at 3:13 p.m.
Measles


Measles continues to rip through unvaccinated communities across the United States.

The virus has sickened at least 4,410 people this year, according to a report today from the Centers for Disease Control and Prevention (CDC). The total number of measles cases grew by 8%, or 330 cases, in just the past seven days. That’s more than the total number of measles cases in all of 2024, when the CDC confirmed 285 cases.

There have been 42 new measles outbreaks across the country this year. Of the confirmed cases, 96% have been in people who are unvaccinated or have unknown vaccination status.

The true number of measles cases is likely to be substantially larger, according to public health experts. Pennsylvania has reported six measles deaths, a much higher number than experts would predict based on the 1,260 cases in that state.

That’s because the expected mortality rate from measles ranges from one to three deaths per 1,000 infections. Based on those historic rates, infectious disease specialists say the true number of measles infections in Pennsylvania could be 6,000 or more.

The discrepancy could be due to underreporting of milder cases in people who don’t need to be hospitalized. In traditional communities hit hard by the measles, including the Amish or Mennonite communities, parents often take care of children with measles at home, rather than bring them to a doctor, who would report the case to the health department.

“Our detection of disease is only as good as our reporting,” said Robert Hopkins, MD, medical director of the National Foundation for Infectious Diseases.

CDC officials headed to PA​

The CDC has sent one of its elite “disease detectives” to Pennsylvania to help control measles outbreaks in multiple counties, according to NBC News.

In an interview with Spectrum News 1 yesterday, Secretary of Health and Human Services (HHS) Robert F. Kennedy Jr. said he will bring the Pennsylvania measles outbreak, which began in February with five cases in Lancaster County, “to a quick close.”

But the CDC still only acknowledges two measles deaths so far this year. The agency says it’s working with the Council of State and Territorial Epidemiologists (CSTE) to develop a standardized case definition for deaths due to measles. A CSTE spokesperson told CIDRAP News that they anticipate it will take two to three months to complete the work.

Measles has been spreading across the country since January 2025, when an outbreak began in Texas. Kennedy became HHS secretary the next month. The CDC reported 2,289 measles cases last year, along with the deaths of two children and one adult.

In addition to Pennsylvania, other states with notable measles activity include Kentucky, which added 66 cases this week and has 170 for the year; New York, which has 126 for the year and recently declared a statewide health emergency; and Ohio, which added 33 cases and is up to 252.