More Than 300 Oklahomans Diagnosed With Mumps

Health officials are investigating a state-wide outbreak of mumps. The contagious infection has showed up in at least seven Oklahoma counties.

Even if you've had your MMR vaccine, that's Measles, Mumps, and Rubella --turns out you're not in the clear-- in fact you could be infected and not even know it.

So far, 324 people have been diagnosed in Canadian, McClain, Osage, Tulsa, Woods, Kay, and Garfield counties. Nearly 300 of those cases have been reported in Garfield County alone, with the first one reported in July.

9/15/16 Related Story: Mumps Outbreak Causes Concern In Enid Schools

And the most unsettling part of the outbreak? Most of the patients had gotten the MMR vaccine, but its only 88 percent effective in preventing mumps.

And while those numbers are concerning, Epidemiologist Megan Holderness with the Oklahoma City County Health Department said Oklahoma isn't alone.

"In the whole U.S. there's about 3600 and that's the highest numbers in a decade,” said Holderness.

She said if you're showing symptoms like fever, headache, body aches and muscle pains, and in some cases--extreme swelling of the jaw or throat, go to the doctor and then stay home.

"Stay out of the school settings and crowded environments five days after that swelling begins,” continued Holderness.

Health officials say it's important to diagnose people with mumps, that way they can go to those locations and find out where the outbreak started. Then, they can start treatment in that area.