kids can definitely learn not to bother you, my daughter used to come in the door asking "daddy, are you having a meeting?" cause she knows those moments are more critical :).

But they are kids nonetheless, if you are in your "office" room (provided you have one) and next room your kids are screaming it's still disruptive (though headgear might help).

If you have >1 kids and they are home sick, I suggest just working from some other place for a couple days.