Newer testing methods suggest significant silent spread of measles in the U.S., threatening elimination – CTV
April 24, 2026
Measles crept into Utah and Arizona in June, with reports trickling into local health departments of patients coming to doctors and saying their children had just recovered from full-body rashes, and parents telling pediatricians that their whole family had just recovered from measles.
But because patients would decline testing, there were no official cases in the outbreak until August 8, when the Mojave County, Arizona, Department of Public health received a report about a 10-year-old boy who lived in a tightly knit community that spans the border of northern Arizona and southern Utah.
That outbreak has grown to more than 600 reported cases and is now the most active in the U.S. The Arizona-Utah cases will almost certainly be important to determining whether the US has lost its measles elimination status, meaning it’s stopped the routine transmission of the virus within its borders for over a year. The meeting to make that determination is now set for November.
The U.S. Centers for Disease Control and Prevention tasked one of its disease detectives with using molecular evidence – clues buried deep in the genomes of the measles viruses that infected patients – to learn more about when the outbreak really started and how large it actually is.
