Secondary infection is a thing. Antibiotics may be prescribed to reduce the risk of that.
And god forbid, mom/dad get it. I almost died from some crap my daughter brought home because the doctor sent me home twice with a "suck it up" attitude (after I had been "sucking it up" for nearly two months), until I ended up in the emergency room at 1AM with pneumonia, a massively elevated temp, and a pleural effusion that was so painful I could barely breath. The doctor that sent me home called a couple days later (because they took blood samples and some swabs) with a "we have to see you now" call, at which point I was like, yah thanks a lot for nothing...