The United States has recorded 4,410 measles cases as the outbreak rises

The CDC reports 451 hospitalizations nationwide as health officials expand vaccination efforts.

The U.S. Centers for Disease Control and Prevention (CDC) has recorded 4,410 measles cases so far in 2026, an increase of 330 cases in one week, and has sent a researcher to Pennsylvania to help contain the nation's largest outbreak.

CDC figures also show 451 measles-related hospitalizations nationwide this year. Children and adolescents aged 5 to 19 make up 42% of cases, followed by adults aged 20 and over, who make up 41%. Seventeen percent of cases were among children under five years of age.

List 3 Cases List 1 of 3 The CDC reports two measles deaths in the United States, the highest level of cases in 35 years.

List 2 of 3 Pennsylvania confirms fifth measles death as US outbreak rises.

3 of 3 New York states declare measles disaster amid resurgence of disease in US

As of Wednesday, Pennsylvania had reported 1,222 cases in 42 counties, including 86 new infections since Oct. 9, according to the state Department of Health. The outbreak has resulted in 225 hospitalizations and 5 confirmed measles-related deaths. State officials are actively investigating the sixth reported death.

The CDC is sending a so-called "disease detective" from its Epidemic Intelligence Service to work with state health officials on the Pennsylvania outbreak. The deployment follows Pennsylvania's request for federal aid, known as Epi-Aid.

Pennsylvania has expanded vaccination efforts in affected communities. Public health center staff have administered more than 5,900 doses of measles, mumps and rubella (MMR) vaccine at 202 pop-up clinics since the outbreak in late April.

New York Gov. Kathy Hochul declared a statewide emergency on Oct. 5 as measles cases spiked in Pennsylvania. The order is in effect until Nov. 4 and expands the number of health care professionals authorized to administer the vaccine and allows nurses more flexibility to order measles tests.

Measles vaccination coverage among U.S. kindergartners dropped from 95.2 percent in the 2019-2020 school year to 92.4 percent in 2025-26, according to CDC data. The agency estimates that about 280,000 kindergarteners are at risk because of gaps in vaccination coverage.