What's a Virus?
A virus is a very tiny type of germ. Viruses (say: VY-ruh-sez) can get inside the body and make a person sick. Viruses cause colds, chickenpox, measles, the flu, and many other illnesses. Antibiotics only work on bacteria, not viruses. So wash your hands often to help prevent the spread of viruses, especially before you eat and after you use the bathroom.