Knoxville (WVLT) - Four area school systems are now closed for the rest of the week, due to flu and other illnesses.
Scott County Schools, Oneida Special Schools, Claiborne County Schools and McCreary County, Kentucky Schools are also closed through Friday.
But how and when does a district make the decision to close schools and why is the classroom such a hotbed for viruses in the first place?
Many East Tennessee school systems are yet to close due to weather, but some already are closed due to illness and flu season hasn't even begun to peak here.
Many factors go into the decision to close, but there are ways to help keep your child healthy.
They're in close quarters, sharing school supplies and swapping lunches and, in turn, spreading germs.
It should be no surprise students seem to come down with the same illnesses at once.
Flu and other viruses closed schools in Scott County, which is reporting about a 13 percent absentee rate.
Claiborne is also closed, with nearly 17 percent of the students out sick.
And McCreary County, Kentucky, schools are also closed.
So, how many sick students are too many to continue on with class, as usual?
"If we get up to 15 or 20 percent and start giving some real close consideration there, but the level can differ from school to school," says Knox County Schools Spokesman Russ Oaks.
And from county to county, ultimately, it's the superintendent who decides whether students need a break from each other, or rather, each other's germs.
Students may be exposed to hundreds of viruses a day, but there are some things you can teach them to fight these viruses off.
"Number one, hands down, no pun intended -- wash your hands!" says pediatrician Dr. Michael Green.
Encourage your child to use warm, soapy water and rub vigorously for at least 20 seconds, about the time it takes to sing happy birthday twice.
Send your child equipped with sanitizing wipes and hand sanitizer.
Also, send your child equipped with mechanical pencils. Odd? Not so says Dr. Green. "That's a common place, a common thread that all those kids in the class are going to use is a pencil sharpener."
Send virucidal tissues to school with your child.
They prevent the spread of viruses, because they kill them when you blow your nose.
Supply them with their own crayons, art supplies can be germ carriers.
And encourage them to hang their backpack on a hook if they have to take it to the school restroom.
The same holds true for any of us who carry a purse or briefcase.
One study found about 25 percent of women's purses have fecal material on the bottom, because women put them down on the floor of the restroom stall.
Most hooks have been lowered, so thieves can't steal your purse from over the top of the stall, so, make sure you use those hooks!