US measles cases reach 4,588 this year, up 178 in a week

The CDC's weekly update counted 4,588 confirmed cases across 47 jurisdictions as of Oct. 22, including 18 among international visitors. Reuters reported the total was up 178 from a week earlier. About 96% of cases are linked to outbreaks.

Pennsylvania has reported 1,317 cases as of Oct. 21, according to state data cited by Reuters. The state health department has reported five measles-related deaths this year, while the CDC has confirmed three. Children and teens aged 5 to 19 are the largest group, at 42% of cases.

Why it matters: Measles is highly contagious, and the weekly rise shows the outbreak is still growing. The CDC has said it would send more support to Pennsylvania to help investigate.