Hepatitis describes any of a number of distinct viral diseases which impair liver function. They vary in severity, ease of transmission, and the ability to be vaccinated. The three most common are:
hepatitis A - The easiest to catch; it can be passed on through infected items or food. It can be vaccinated against, and such vaccinations are recommended for persons who travel to unhygienic or tropical environments. Infections can usually be successfully treated.
hepatitis B - Harder to catch, usually requiring direct person to person and fluid to blood contact. Symptoms are more severe and harder to treat. It can be vaccinated against, but as it cannot be passed through casual contact, vaccination is generally only recommended for adults.
hepatitis C - Very difficult to catch, usually requiring direct blood to blood contact from an infected person. Until it could be successfully tested for, it was very common for persons who used blood products, such as hemophiliacs and recipients of blood transfusions, to be infected with it. No effective vaccine is known. It is treatable, but symptoms are usually very severe and can be life threatening.