There are six main types of viral hepatitis: A, B, C, D, E, and G. The three main types in the United States are hepatitis A, B, and C. Vaccines can prevent some viral hepatitis infections.
Hepatitis is an inflammation of the liver. It usually results from a viral infection, but drugs, toxins, and certain diseases, including autoimmune diseases, may also cause the condition.
The symptoms of hepatitis may be mild, but the condition can lead to severe complications. For example, each type of hepatitis can cause fulminant hepatic failure (FHF), which affects the liver.
Hepatitis may be acute or chronic. Acute hepatitis is short-term, lasting less than 6 months. Chronic hepatitis is long-term, lasting more than 6 months. Hepatitis C is the most common cause of chronic hepatitis.
The HAV vaccine can prevent hepatitis A. This shot is routine for infants between the ages of 12 and 23 months. Unvaccinated children older than 23 months, adolescents, and adults should also have this shot.