The Associated Press

U.S. health officials say this year’s count of measles cases has surpassed 800, a growing tally that is already the nation’s highest in 25 years.

A total of 839 cases were reported as of last week. That’s the most since 1994, when 963 were reported for the entire year. The Centers for Disease Control and Prevention released the numbers Monday.

In all, 23 states have reported cases this year. The majority of illnesses have been in New York, most of them among unvaccinated people in Orthodox Jewish communities.

Measles was once common but gradually became rare after vaccination campaigns that started in the 1960s.

Parents in Washington state will no longer be able to claim a personal or philosophical exemption for their children from receiving the combined measles, mumps and rubella vaccine before attending a day care center or school under a measure signed Friday by Gov. Jay Inslee. The state saw more than 70 cases of measles this year. The new law takes effect at the end of July.

Washington is among 17 states that allow some type of nonmedical vaccine exemption for personal or philosophical beliefs; Oregon, which saw a handful of cases tied to the Washington outbreak, is among them.