LOS ANGELES, Oct. 17 (Xinhua) -- The United States reported 4,410 confirmed measles cases in 2026 as of Thursday, nearly double the 2,289 cases reported for all of 2025, putting the country on track for its highest annual total since 1991, according to the latest data from the U.S. Centers for Disease Control and Prevention (CDC).
Of the confirmed cases, 4,392 were reported by 47 jurisdictions, while 18 cases were reported among international visitors to the United States, the CDC said.
Children and adolescents aged 5 to 19 accounted for the largest share of cases, with 1,856 infections, or 42 percent of the total.
A total of 451 patients, or about 10 percent of all confirmed cases, have been hospitalized. About 96 percent of cases were among people who were unvaccinated or whose vaccination status was unknown, according to CDC data.
Meanwhile, the outbreak in the U.S. state of Pennsylvania continues to grow. The Pennsylvania Department of Health said on Friday that 1,260 measles cases have been confirmed across 43 counties in the state so far this year, including 238 hospitalizations and five confirmed measles-associated deaths.
The state reported 38 new cases since Wednesday. It is also investigating a recently reported death in Franklin County, the department said.
The CDC plans to send one of its scientists to Pennsylvania to help respond to the outbreak, NBC News reported Thursday, citing a CDC spokesperson. The scientist, an officer with the agency's Epidemic Intelligence Service (EIS), is expected to arrive later this week. EIS officers are often referred to as "disease detectives" because of their work investigating disease outbreaks.
"CDC will continue working closely with Pennsylvania health officials to provide the expertise and support needed to respond to the outbreak and protect public health," the CDC spokesperson was quoted as saying.
The CDC recommends two doses of the measles, mumps and rubella vaccine as the best protection against measles.
The agency says that when more than 95 percent of people in a community are vaccinated, community immunity, also known as herd immunity, helps protect more people from the disease. ■
