06. Hepatitis A Virus

Resident Editor: Allison Kwong, MD

Faculty Editor: Sarah Summerville, MD


✔ Usually a self-limited illness with excellent prognosis; transmitted by fecal-oral route

✔ Supportive care is usually the only treatment necessary

✔ Report cases to the CDC!


  • Acute hepatitis A virus (HAV) was previously the most common viral hepatitis in the US, but incidence has decreased 95% since HAV vaccine became available in the mid-1990s.
  •  Self-limited illness
    • Hepatitis A is never chronic
    • Fewer than 1% of cases progress to fulminant hepatic failure, but higher risk of fulminant liver failure due to hepatitis A infection in patients with pre-existing liver disease (i.e. chronic hepatitis B or C, alcoholic liver disease).
  • Transmission is primarily via the fecal-oral route
    • Contact with infected sex partner or household members
    • Ingestion of contaminated water or food (i.e. shellfish)
    • Saliva and serum have very low levels of virus, HAV has never been detected in urine, semen, or vaginal secretions, and maternal-fetal transmission has never been described
  •  High risk groups: men who have sex with men (MSM), travelers to countries with endemic transmission, low socioeconomic conditions, poor sanitation, and users of injection drugs
  • Immunity and vaccination
    • Infection confers lifelong immunity – no need to vaccinate individuals with positive HAV IgG
    • ACIP recommends vaccination for all persons at increased risk for infection or increased risk of complications (i.e. those with pre-existing liver disease or clotting disorders)
    • Immune globulin is an alternative or adjunct to the vaccine in certain populations (e.g. immunosuppressed individuals who cannot mount an adequate response to the vaccine, at-risk individuals who do not have time to receive the full two-dose vaccination series prior to travel, or those with allergies to the vaccine)

Signs and Symptoms

  •  The viral incubation period ranges from 15-49 days (average 30 days).
  •  Symptoms occur in >70% of infected adults and usually last less than 2 months but can last up to 6 months.
  •  Prodrome – fatigue, weakness, anorexia, nausea, vomiting, RUQ abdominal pain, fever, headache, arthralgias, diarrhea can occur before the onset of “classic” symptoms. Looks similar to other viral hepatitides.
  •  “Classic” symptoms – jaundice, dark-colored urine, acholic stools usually occur 1-2 weeks after onset of prodromal symptoms. However, the majority of infections are ultimately anicteric. Older age is associated with worse liver inflammation and jaundice. 
  •  Serum aminotransferase elevation peaks during the most symptomatic portion of the prodromal phase. 


  •  Physical exam: 
    • Jaundice and hepatomegaly are the most common physical exam findings
    • Extrahepatic manifestations can include: vasculitis, arthritis, optic neuritis, transverse myelitis, thrombocytopenia, aplastic anemia and red cell aplasia
  • Laboratory evaluation:

    If acute infection suspected:

    • Measure anti-HAV IgM. The IgM antibody is usually positive at onset of symptoms  stays positive for up to 12 months, so may reflect past exposure and not acute infection.
    • ALT/AST, bilirubin (total and direct), alkaline phosphatase should be checked (ALT>AST and can be >1000)
    • No need to order HAV IgG when attempting to determine acute infection

    Determination of past infection or need for vaccination:

    • Measure anti-HAV IgG (or termed HAV Ab Total)
      • A common error is ordering HAV IgM rather than HAV IgG when attempting to determine immunity


    •  Treatment is supportive only: fluids, rest, and adequate nutrition are the mainstays.
    •  Hepatitis A vaccine or immune globulin can be effective for post-exposure prophylaxis if given within 2 weeks of a known exposure, though usually not necessary.
    •  Potentially hepatotoxic drugs (e.g. acetaminophen) should be avoided.  
    •  Alcohol should be avoided completely until symptoms have fully resolved.
    •  Can feel ill for up to 8 weeks and miss 30 days of work

    Prevention and Vaccination

    •  Report all cases to the CDC!
    •  Patients are most contagious 2 weeks before and 1 week after symptoms
    •  Heating food or water to 185°F will kill the virus.  See “Adult Immunization” and “Travel Medicine” chapters for more information on vaccination.


    Centers for Disease Control and Prevention. “Hepatitis A Questions and Answers for Health Professionals.” https://www.cdc.gov/hepatitis/hav/havfaq.htm#general. Accessed 03/31/2018.

    Centers for Disease Control and Prevention. Viral Hepatitis Surveillance: United States, 2015. https://www.cdc.gov/hepatitis/statistics/index.htm. Accessed 03/31/2018.

    Taylor RM, Davern T, Munoz S, Han SH, McGuire B, Larson AM, Hynan L, Lee WM, Fontana RJ, US Acute Liver Failure Study Group.  Fulminant hepatitis A virus infection in the United States: Incidence, prognosis, and outcomes. Hepatology. 2006;44(6):1589.

    Vento S, Garofano T, Renzini C, Cainelli F, Casali F, Ghironzi G, Ferraro T, Concia E, 

    Fulminant hepatitis associated with hepatitis A virus superinfection in patients with chronic hepatitis C. N Engl J Med. 1998;338(5):286.

    Schiff ER, Atypical clinical manifestations of Hepatitis A.  Vaccine. 1992;10 Suppl 1:S18.