The Centers for Disease Control and Prevention (CDC) said today the country has seen 1,618 confirmed measles cases so far in 2025, 22 more than last week. And in South Carolina, a measles outbreak linked to two schools with low student vaccination rates has grown by 4 cases.
The total represents the most US infections since 1992, when the CDC reported 2,237 measles cases.
Upstate South Carolina outbreak hits 20 cases
The South Carolina Department of Public Health (DPH) said in a press release yesterday there were 4 more confirmed cases in Spartanburg County, raising the state's total number of measles cases this year to 23.
Twenty of the 23 cases, including the 4 most recent, are part of the current Upstate outbreak that is focused in Spartanburg County. Two of the recent patients are close contacts to known cases who have been quarantining at home, and two are associated with a business in Spartanburg with no public exposures.
“Some cases are travel-related exposures or close contacts of known cases. Other cases have no identified source, suggesting that measles is circulating in the community and could spread further,” DPH said. "We have seen measles spread quickly in unvaccinated households here in South Carolina. We also know that it can spread quickly in unvaccinated communities based on outbreaks in other states."
We have seen measles spread quickly in unvaccinated households here in South Carolina. We also know that it can spread quickly in unvaccinated communities based on outbreaks in other states.
Today and tomorrow, exposed students will return to in-person learning at two schools that were associated with the Upstate outbreak.
Southwest has high case count
Elsewhere in the country, measles activity is still high in Utah and Arizona, with more than 100 cases reported in neighboring counties, including Mohave County, Arizona, which has seen 80 cases. Experts say the outbreak, similar to the major West Texas outbreak earlier this year, is rooted in communities with historically low vaccination rates.
Of the 1,618 measles cases in the United States, 87% are part of 43 outbreaks of three or more related cases.
"For comparison, 16 outbreaks were reported during 2024, and 69% of cases (198 of 285) were outbreak-associated," the CDC said.
Twelve percent of cases this year have required hospitalization (198 of 1,618), including 95 children under the age of 5 years. Three people have died from measles.
Ninety-two percent of cases in the United States are in unvaccinated people or those whose vaccine status isn't known.
