There have now been 940 confirmed cases of measles in the U.S. since the start of the year, federal health officials announced Monday.
The latest numbers from the Centers for Disease Control showed 60 more cases had been added since last week.
The current outbreak is the highest number of measles cases reported in the U.S. since 1994 and since the disease was declared eliminated in 2000, the CDC noted.
As the outbreak has grown, federal officials have urged everyone to make sure they've received a measles vaccination.
Measles symptoms typically appear seven to 14 days after a person is infected and includes high fever, cough, runny nose and red or watery eyes, according to the CDC. Measles can also lead to serious complications including pneumonia or encephalitis, which is a swelling of the brain.
So far this year, measles cases have been reported across 26 states including: Arizona, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Maine, Maryland, Massachusetts, Michigan, Missouri, New Mexico, Nevada, New Hampshire, New Jersey, New York, Oklahoma, Oregon, Pennsylvania, Texas, Tennessee, and Washington.