The most recent cases involve an adult and a child, both unvaccinated household members in Tarrant County, health officials said. The source of the infection has not been determined.

There have been 935 confirmed cases of measles across nearly 30 states so far this year, according to the latest update from the CDC on Friday, an increase of 51 over the last week and far surpassing the 285 measles cases reported in the entirety of 2024 (the CDC does not provide data on how many cases are actively infectious).

The measles outbreak centered in northwest Texas grew to 683 cases and spread to three new counties on Friday, according to health officials. The latest update from the Texas Department of State Health Services adds 20 new cases since the agency's last update on Tuesday.