The US now has almost 1,800 measles cases.
In international developments, Israel has now confirmed 10 measles deaths in children this year.
Together Mohave County, Arizona, and southwestern Utah have 201 cases.
Overall, 63% of Americans say they are extremely or very confident that routine childhood vaccines are effective at preventing serious illness.
Today the South Carolina Department of Health reported 5 new cases in Spartanburg County.
Increased early vaccination began in February, perhaps due to clinician and/or parental concern, the authors say.
Last year the US had 285 measles cases.
Eight more cases were reported by the South Carolina Department of Public Health today.
Nashville also reported its first measles case in 20 years.
Canada had eliminated measles in 1998, 2 years prior to the United States.
