Confirmed measles cases in the U.S. have risen to 712, more than doubling last year’s total, according to an April 11 CDC report.
Health officials across several states, including Indiana, Ohio and Michigan, are investigating new clusters of cases as they work to contain the virus.
Here are seven things to know:
- The Indiana Department of Health has reported six confirmed measles cases in Allen County, including four unvaccinated individuals and two adults whose vaccination status is unknown. Officials said the cases are linked but are not connected to the measles outbreaks in other states.
- Ohio has also reported 24 cases across two counties, with 10 confirmed cases in Ahtabula County in Northeast Ohio and 14 reported in Knox County in Central Ohio. Seven cases were tied to a single exposure, the state health department said.
- In Michigan, a Montcalm County resident tested positive after recently traveling outside of the state, marking the state’s fourth confirmed case this year.
- In addition, a third case in Philadelphia was reported April 11 from an individual who was exposed while studying abroad. “Sadly, we have identified another case of measles in our region. We believe there is no threat to the general public because of this case,” said Palak Raval-Nelson, PhD, commissioner of the Philadelphia Department of Public Health.
- The most recent CDC data showed that nearly all measles cases this year involve people who are unvaccinated or whose vaccination status is unknown. Only 3% of patients who contracted the virus received at least one MMR vaccine.
- So far in 2025, 11% of measles patients have been hospitalized, and 20% of the patients hospitalized have been children younger than 5. Two deaths from measles have been confirmed and another is under investigation.
- In an April 10 letter, American Academy of Pediatrics President Susan Kressly, MD, urged Congress to act to stop measles outbreaks by promoting vaccination and restoring funding for vaccine-related programs and federal health workers.
“It is critical that Congress ensure that the federal government provides the resources necessary for state and local governments and non-governmental organizations to prevent measles infections through access to vaccines, and that these entities have the tools they need to effectively respond to the outbreak,” she wrote.
