Knoxville (WVLT) -- Flu season is getting worse before it gets better.

The latest flu count from the Knox County Health Department shows the biggest jump yet in the number of flu cases.

Last week's reporting data indicates 737 new cases, compared with just 562 new cases the week prior.

For a total of 1,658 flu cases reported since the season began October first.

We're covering East Tennessee health with details on what these latest numbers indicate about this year's flu season.

The flu season got off to a slow start in East Tennessee, but it sky-rocketed in February, and is showing no signs of slowing down.

Dr. Kip Wenger works in the UT Medical Center emergency department and says, "All the hospitals and emergency departments in the area have seen a big spike in their volume and certainly we have, too. So, it makes it difficult to take care of all the patients at times."

After treating an uncharacteristically low number of patients on Friday, less than 130, doctors and nurses at UT Medical Center's emergency department hoped they'd seen the worst of the flu season.

But the number of patients climbed right back up Saturday and Sunday to more than 200.

Supporting the latest flu count from the Knox County Health Department, which saw the biggest increase yet this year, more than 700 confirmed flu cases.

Knox County Public Health Officer Dr. Martha Buchanan says, "The numbers are going up at a rate which is normal for flu season, again it's a little bit late this year, but the numbers are climbing steadily which is what we expect them to do."

Perhaps what is unexpected is the less-than-perfect vaccine, which is a good match for only about 40 percent of the virus spreading now.

In Knox County, about double the number of people are sick with flu this year compared to last.

Wenger says, "Oh, absolutely. We're seeing a huge increase in flu and all the related illnesses that go with it, it's been particularly tough on the very old and very young."

It's not uncommon for there to be peaks and valleys to the flu season.

Buchanan says, "The flu season started a little bit late. And just because it started late, doesn't mean it's going to follow a different pattern, it's going to follow the same pattern it does every year. We're going to see a climb in cases until we peak, and then we'll start going back down."

And we certainly haven't seen the last of it yet.

Public health leaders say it's still a good idea for people to get a flu shot, especially the most vulnerable ones.

The very old, the very young and those with certain health conditions.