Measles cases in the United States have reached their highest number in more than 30 years, according to new federal data published Wednesday.

The number of reported measles cases in the United States has hit 1,288 in the first six months of this year, the most since the disease was declared eliminated in 2000.

The number of measles cases in the U.S. has reached a 33-year record high, years after it was officially eliminated in the country, prompting public health experts to sound the alarm that other diseases could experience a similar resurgence.