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LEARNING OBJECTIVES
Upon completion of the chapter, the reader will be able to:
Differentiate the five types of viral hepatitis by epidemiology, etiology, pathophysiology, clinical presentation, and natural history.
Identify modes of transmission and risk factors among the major types of viral hepatitis.
Evaluate hepatic serologies to understand how the type of hepatitis is diagnosed.
Create treatment goals for a patient infected with viral hepatitis.
Recommend appropriate pharmacotherapy for prevention of viral hepatitis.
Develop a care plan for treatment of chronic viral hepatitis.
Formulate a monitoring plan to assess adverse effects of pharmacotherapy for viral hepatitis.
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The most common types of viral hepatitis include hepatitis. Acute hepatitis may be associated with all five types of hepatitis and rarely exceeds 6 months in duration. Chronic hepatitis (disease lasting more than 6 months) is usually associated with hepatitis B, C, and D. 
Chronic viral hepatitis may lead to the development of cirrhosis and may result in end-stage liver disease (ESLD) and hepatocellular carcinoma (HCC). Complications of ESLD include ascites, edema, hepatic encephalopathy, infections (eg, spontaneous bacterial peritonitis), hepatorenal syndrome, and esophageal varices. Therefore, prevention and treatment of viral hepatitis may prevent ESLD and HCC.
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Viral hepatitis may occur at any age and is one of the most common causes of liver disease in the world. The true prevalence and incidence may be underreported because most patients are asymptomatic. The epidemiology, etiology, and pathogenesis vary depending on the type of hepatitis and are considered separately below.
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EPIDEMIOLOGY AND ETIOLOGY
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HAV affects 1.4 million people yearly worldwide.1 The prevalence is highest in economically challenged and underdeveloped countries, including Central and South America, Africa, the Middle East, Asia, and the Western Pacific.2 The numbers of acute HAV infections and hospitalizations have decreased since the introduction of the HAV vaccine in 1995.2 However, there has been a recent resurgence of hepatitis A infections in the United States since 2017 affecting primarily the homeless and people who inject drugs (PWID). As of August 2020, more than 33,000 cases have been reported, up from 12,474 in 2018.3,4
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HAV is primarily detected in contaminated feces and infects people via the fecal–oral route.1,2 Outbreaks typically occur in areas of poor sanitation or consumption of food or water infected with the HAV.1,3 About 40% of the cases reported have no identifiable risk factors; individuals at greatest risk of acquiring HAV are listed in Table 25–1.4
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