The measles outbreak in New York drove another increase across the U.S. in an already historically bad year for the disease, the Centers for Disease Control and Prevention said Monday.

The federal health agency confirmed 60 new cases last week, bringing the 2019 total to 764 — highest in 25 years. It's also a record number of cases since the disease was declared eliminated in the U.S. in 2000. Of the new 60 cases, 52 were reported in New York, where two large outbreaks are occurring.

In New York City, 41 new cases were confirmed, the CDC said. Eleven new cases were confirmed in suburban Rockland County. Health officials in both communities are urging people to vaccinate and are trying to control the disease from spreading.

Cases have now been confirmed in 23 states this year, with Pennsylvania being the newest addition.

Measles is highly contagious yet preventable with a vaccine for measles, mumps and rubella. More parents are refusing to vaccinate their children, sometimes based on false information that vaccines cause autism. The disease spreads quickly and easily among people who aren't immunized, leaving communities with high rates of people who aren't protected vulnerable.

Six of the 13 outbreaks in the U.S. were associated with close-knit religious or cultural communities with lower immunization rates, the CDC said last week. Yet they accounted for 88% of all cases this year, highlighting how easily the disease can spread among people who are not vaccinated. The agency defines outbreaks as three or more cases.

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Health officials are warning that the longer the outbreaks continue, the greater the chance that measles will "again get a sustained foothold in the U.S."

Measles starts with a fever, runny nose, cough, red eyes and sore throat. It then causes a rash. Some people develop severe complications, such as pneumonia or brain swelling. Children younger than 5 and adults older than 20 are more likely to experience complications, making the disease especially dangerous for them.