The ongoing measles epidemic is now the largest since the disease was declared eliminated in 2000, according to a report from CNN.

CNN analyzed data from 22 states that have reported confirmed cases of the measles this year and determined 681 cases have been declared. That beats the previous high of 667 in 2014. Confirmed cases have been found in rizona, California, Colorado, Connecticut, Florida, Georgia, Illinois, Indiana, Iowa, Kentucky, Maryland, Massachusetts, Michigan, Missouri, Nevada, New Hampshire, New Jersey, New York, Oregon, Tennessee, Texas and Washington.

On Monday, the Center for Disease Control released its weekly report which says there were only 626 confirmed cases in the U.S., but also stated the numbers of reported cases will eventually surpass 2014 regardless of the exact date of when that will happen. The CDC’s data was current as of April 19.

The CDC also reports that of the 626 cases it has confirmed, 487 of those people were 19 years old or younger. The spread of the highly contagious disease has been largely restricted to communities of unvaccinated people.

Spreading of the disease can happen quickly as the virus can live up to two hours in the air where the infected person coughed or sneezed. However, symptoms don’t usually show up for a week or two after exposure meaning it can be spread by people who’ve been infected but don’t know they have the measles and may assume it’s a cold or other illness.

Symptoms include a high fever, cough, runny nose, red and watery eyes, tiny white spots in the mouth and a red rash on the face that spreads to the extremities.

The easiest way to prevent measles is to be vaccinated against the disease. If you’ve been exposed to the disease, a vaccines will begin working within 72 hours of exposure.

“The measles vaccine is highly effective and very safe. A single dose of measles vaccine protects about 95 percent of children, but after two doses, almost 100 percent are immune," Michigan’s health department said in a press release.

“The first of two routine childhood measles vaccine doses is given at 12-15 months of age. A second vaccine dose is given before the start of kindergarten, between ages 4 and 6 years.”

If you believe you may have come in contact with the disease, you should call your doctor before going to their office as you may spread the disease even more.