Why can antiseptic kill bacteria but can't kill virus when children get sick caused by virus? Thanks

Antibiotics. Antiseptics (such as bleach or alcohol) can kill both bacteria and viruses. Antibiotics, on the other hand, are medications that interfere with specific biological processes present only in bacteria (usually the reproduction process), which results in the death of the bacteria. These processes are not present in viruses, which have a different reproductive method, so antibiotics will not work.
Viruses are breathed. Usually this is because viruses are breathed in from the air and not transmitted from surfaces of inanimate objects.