They are wet and sticky. Germs get stuck in our throat and mouth and don't go any further. If the germ passes through our skin, nose, or throat and mouth and gets into our blood stream, there are special cells in our blood that fight germs. There are two types of fighting cells in our body, white blood cells and antibodies. White blood cells eat harmful germs.
Antibodies attack specific germs that they have been in contact with before.
For example, if you have had the chicken pox before your body has created antibodies to the virus that causes chicken pox. If you are exposed to the chicken pox again these antibodies will attack that virus. This is why you can only get the chicken pox once. Hand washing is important because it reduces the spread of germs from one person to the next. By washing our hands, we prevent germs from getting into our bodies as well as passing them onto other people.