With three months left of 2026, the United States is closing in on a number of measles cases that would have been unheard of just a couple years ago. With 228 new cases logged this week, the country reached 3,886 infections, just 114 shy of 4,000, according to the Centers for Disease Control and Prevention’s (CDC’s) weekly update today.

It could top that milestone next week. And US cases could be more than double the 2025 total this month.

The national wave comes as Pennsylvania, the nation’s hot spot, adds more than 100 new cases in the past week to its total for the year. More than two-thirds of the cases in the state involve adults.

The CDC continues to tally just two measles-related deaths, and it has not specified where they occurred. Pennsylvania this week confirmed a fifth measles-associated death. The previous case involved two infants and two adults, but the Pennsylvania Department of Health (DOH) didn’t specify the age range for the latest death.

Last year, the CDC confirmed that three people, including two children, died of measles. But this year, the agency has taken the unusual step of saying measles deaths must be confirmed by the National Center for Health Statistics (NCHS). Some say this approach adds confusion, as NCHS data are typically used to assess long-term trends, not to confirm new deaths. It has also introduced a substantial delay in confirming the deaths in Pennsylvania.

Today’s increase in US cases marks the eighth straight week of triple-digit increases in cases.

The CDC today noted 42 outbreaks, two more than last week. Last year saw 48 measles outbreaks, defined as three or more related cases. Total cases for all of 2025 reached 2,289, which was the most since 1991 until the country surpassed that level in July. Cases in 2024 reached just 285.

All but 18 of this year’s cases have been locally acquired, with the rest tied to international travel. Cases have been confirmed in 45 states plus New York City and Washington, DC.

Of the 2026 cases, 18% involve children younger than 5 years, and 61% involve kids and teens. Nine percent of patients have been hospitalized, compared with 11% in 2025. Among all measles patients, 95% are unvaccinated or have an unknown vaccination status. 

In an update today, the Pennsylvania DOH added 34 new infections in the past two days and 102 cases in the past week, bringing the state’s 2026 total to 977. The state has the most cases for 2026.

Lancaster County has by far the most cases in the state, with 391, followed by Mifflin (117), Chester (83), Jefferson (44), and Snyder (41).

The CDC’s measles map lists 670 infections this year in South Carolina, though its outbreak—which totaled 997 cases for 2025 and 2026—was declared over on April 27. Utah is listed third on the CDC map, with 535 cases (eight new), followed by Wisconsin (207; 43 new), Texas (192), Virginia (178), Florida (148), and Ohio 144 (10 new).

The MMR [measles, mumps, and rubella] vaccine, administered over two doses, boosts a person’s immune system and provides 97% lifetime protection.

Of Pennsylvania’s total, more than 99% of cases involve unvaccinated or undervaccinated people. Of the 977 patients, 195 (20%, or about one in five) have required hospitalization. As opposed to the national trend, 69% of those infected have been adults.

The DOH said, “The best protection against measles remains getting fully vaccinated. The MMR [measles, mumps, and rubella] vaccine, administered over two doses, boosts a person’s immune system and provides 97% lifetime protection.”

Cases in other states are also climbing. The Wisconsin Department of Health Services today added 72 infections to its total, which has now grown to 243. Kentucky added 27 new cases and has 94 for the year. And Ohio’s health department lists 206 measles cases, which is 17 more than last week. Utah lists 527 cases, nine of which are new.