US Measles Cases Reach 4,588 as Pennsylvania Count Rises to 1,338

Updated 20:21 UTC. The CDC reported 4,588 measles cases in the United States as of Oct. 22, up 178 from a week earlier, Reuters reported on Friday. Measles related hospitalizations this year stand at 479. Pennsylvania reported 1,338 cases as of Oct. 23, with 255 hospitalizations, according to state health department data cited by Reuters. The state has reported five measles related deaths so far in 2026, while the CDC has confirmed three measles associated deaths. Children and teenagers aged 5 to 19 remain the largest group, at 1,914 cases, or 42 percent of the total, followed by adults aged 20 and older at 1,881 cases, or 41 percent, CDC data showed. The CDC has previously said it would send additional support to Pennsylvania to help investigate the outbreak.

Updated 02:31 UTC. The CDC confirmed a third measles related death in the United States on Tuesday, matching the total for all of last year. The Department of Health and Human Services told Reuters the National Center for Health Statistics received a report of the death and verified that measles was the underlying cause. The CDC had reported two deaths in September and has not named the states where the three deaths occurred. Pennsylvania has now reported 1,286 cases as of Oct. 19, up from 1,222 a week earlier, and five confirmed measles associated deaths, all in unvaccinated people. State officials are also reviewing one more death reported by the Franklin County coroner. William Moss, an epidemiology professor at Johns Hopkins, said the country should not have any measles deaths, noting the disease was declared eliminated in the United States in 2000, and he called for a stronger federal push on vaccination in vulnerable communities.

The Centers for Disease Control and Prevention reported 4,410 confirmed measles cases in the United States as of Oct. 15, an increase of 330 cases from its update a week earlier, Reuters reported on Friday. The new count keeps 2026 far ahead of last year. The CDC counted 2,289 cases in all of 2025.

Cases came from 47 jurisdictions, with 4,392 cases reported by states and cities and 18 cases among international visitors to the United States, the CDC said on its measles data page, updated Oct. 16. The agency counted 42 new outbreaks in 2026, and said 96 percent of confirmed cases, 4,228 of 4,410, are linked to outbreaks. Hospitalizations this year stand at 451, Reuters reported.

Pennsylvania is the center of the outbreak

Pennsylvania has reported 1,222 measles cases this year as of Oct. 14, with 225 hospitalizations linked to the disease, according to state health department data cited by Reuters. The state has reported five measles related deaths.

The CDC said on Tuesday it would deploy more support to Pennsylvania to help investigate the outbreak, Reuters reported. Earlier this month, New York declared a disaster emergency for the measles outbreak, the first such declaration by a US state, according to Reuters.

Why the death counts differ

Pennsylvania counts five deaths, while the CDC has confirmed three measles associated deaths in 2026 and has not identified the states involved, Reuters reported. Last month, the CDC shifted to using mortality data from the National Center for Health Statistics for measles related deaths, rather than relying on state health departments, a change that has drawn scrutiny.

The CDC says its death total is subject to change as reviews are completed. The agency also says it is working with the Council of State and Territorial Epidemiologists to develop a standard case definition for deaths due to measles, so states and the federal government classify deaths the same way.

Children and teens are the largest group

Children and teenagers aged 5 to 19 are the largest group affected, at 1,914 cases, or 42 percent of the total, CDC data showed. Adults aged 20 and older account for 1,881 cases, or 41 percent.

Measles was declared eliminated in the United States in 2000, the CDC says. Coverage with the measles, mumps and rubella vaccine among kindergartners has fallen from 95.2 percent in the 2019 to 2020 school year to 92.4 percent in the 2025 to 2026 school year, leaving about 280,000 kindergartners at risk, according to the CDC. The agency says two doses of the vaccine are 97 percent effective at preventing measles, and one dose is 93 percent effective.

The CDC notes that the 2026 case counts are preliminary and can change. State and local health departments lead measles investigations in their areas and hold the most up to date local information.