COLUMBUS, Ohio (WTVN) -- Ohio's measles and mumps outbreaks continue to grow. The mumps cases are closing in on 400 cases while the measles cases have topped 140.

"We see lulls in the action every couple of weeks, but now we're moving into a generation where you're going to see more cases," said Brian Fowler with the Ohio Department of Health who says the number of measles cases has doubled in the last 10 days.

The mumps outbreak appears to have peaked in early April and the number of daily cases has been slowing.

The vaccine for both illnesses is the same, but while it's only 80 to 90 percent effective for the mumps, it's about 97 percent effective for measles.

"The more people we have vaccinated the protected that population will be and the more likely that this will fizzle out," Fowler said.

This is the largest measles outbreak in Ohio since 1990 and the largest in the country since 1996. 

Measles, so far, have been contained to a six-county area in north-central Ohio. The highest numbers are in Knox County.

Mumps have spread to 12 counties, with the vast majority around Columbus and Ohio State University.