Hepatitis A (HAV)

SOURCE

Source: Deming P. Viral hepatitis. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 10th ed. New York, NY: McGraw-Hill; 2017. http://accesspharmacy.mhmedical.com/content.aspx?bookid=1861&sectionid=132516044. Accessed April 10, 2017.

DEFINITION

• Acute, self-limiting viral infection of liver.

• Confers lifelong immunity.

ETIOLOGY

• RNA virus.

  • Genus Hepatovirus of Picornaviridae family.

  • Humans only reservoir.

PATHOPHYSIOLOGY

• Absorbed through stomach or small intestine and taken up by liver.

• Viral replication within hepatocytes and gastrointestinal (GI) epithelial cells.

• Secreted into bile.

  • Cycle continues with reabsorption or excretion into stool.

  • Enterohepatic cycle continues until interrupted by antibody neutralization.

EPIDEMIOLOGY

• Infection primarily occurs through:

  • Fecal-oral route.

  • Person-to-person contact.

  • Ingestion of contaminated food or water.

PREVENTION AND SCREENING

• Routine.

  • Regular handwashing.

    • After using bathroom.

    • After changing diaper.

    • Before food preparation.

  • Traveling in high endemic areas, avoid.

    • Ice and unbottled water.

    • Fresh produce.

    • Uncooked foods.

• Vaccination (Tables 1 and 2)

• Immunoglobulin (Ig)

  • Used when pre- or postexposure prophylaxis against HAV infection needed in persons for whom vaccination not an option.

    • Preferred for persons >40 years old, children <12 months, immunocompromised persons, and persons with chronic liver disease³

  • Most effective within 2 weeks after exposure¹

  • Dosing:

    • 0.02 mL/kg IM for postexposure prophylaxis or short-term (<3 months) preexposure prophylaxis⁶

    • 0.06 mL/kg IM for long-term preexposure prophylaxis (≤5 months)

  • May be given with HAV vaccine, but at different sites¹