Hepatitis A Virus - HAV

The targeted use of the hepatitis A (HAV) vaccine in the U.S. since 1995 has led to a 92% decrease in the number of reported cases of HAV.

  • Diagnosis
  • Algorithms
  • Background
  • Lab Tests
  • References
  • Related Topics

Indications for Testing

  • New onset of jaundice, anorexia, dark urine, abdominal pain
  • Hepatomegaly, splenomegaly, bradycardia, lymphadenopathy, elevated transaminase levels
  • Suspected exposure to hepatitis A virus (HAV)

Laboratory Testing

  • HAV information for health professionals (CDC, 2015)
  • HAV case definition and classification (CDC, 2012)
  • Initial testing (nonspecific)
    • CBC – usually normal
    • Transaminases – usually markedly elevated
  • Testing for acute hepatitis
  • HAV IgM antibodies
    • Diagnose acute HAV infection if exposure is suspected or documented
    • Antibodies generally appear 4 weeks after infection (~5 days before symptoms)
    • May persist up to 6 months after onset of clinical symptoms
  • Total HAV antibodies (IgM and IgG)
    • Assess immunity for HAV from vaccination or previous infection (presence of antibodies is associated with immunity)
    • IgG does not appear until convalescent phase but remains detectable for life
    • Refer to Immunization Status topic for more information

Differential Diagnosis

Epidemiology

  • Incidence – 1/100,000
    • Most common cause of viral hepatitis worldwide
    • 2,000 cases in the U.S. in 2009 (CDC)
    • 50-70% of U.S. adults have antibodies
  • Age – more prevalent among daycare and school-aged children
  • Transmission
    • Fecal-oral (unlike hepatitis B [HBV] or hepatitis C [HCV])
    • Ingestion of contaminated food or water
    • Occurs sporadically or in epidemics
    • Virus only viable on fomites, including produce, for about 1 week
    • Viral shedding in the stool lasts up to 6 months, but period of greatest contagiousness is the 2 weeks prior to onset of jaundice

Organism

  • Nonenveloped RNA picornavirus
  • Infects only primates
  • Survives for extended periods in seawater, fresh water, waste water, and soil
  • Resistant to freezing, detergents, and acids
  • Resistant to bile lysis due to lack of lipid envelope
  • Infects hepatocytes – no propensity for chronic infection

Risk Factors

  • Raw seafood
  • Infected food handlers
  • Daycare settings
  • International travel – accounts for ~50% of cases
  • No specific risk factors found in 70% of U.S. patients

Clinical Presentation

  • Usually asymptomatic or with mild symptoms after incubation period of ~28 days
  • Symptoms include fever, nausea, malaise, jaundice, dark urine, abdominal pain, anorexia
  • Symptoms last an average of 2 months
  • Signs include hepatomegaly, splenomegaly, bradycardia, lymphadenopathy, elevated transaminase levels
  • No chronic hepatitis sequelae
  • Complications – range from asymptomatic to acute, debilitating disease
  • Case fatality rate for HAV infection
    • 0.3-0.6% overall
    • As high as 1.8% among persons >50 years
  • May be prolonged with HIV coinfection
  • Significant liver disease is more likely to result in patients with coinfection of HBV or HCV or in pregnant women

Prevention

  • Universal vaccination against HAV recommended for
    • Children 1-18 years
    • High-risk groups, including men who have sex with men, drug abusers, and people who frequently travel to countries endemic for the virus
  • Strong immunity results even from relatively low vaccination rates
  • Vaccination is recommended prior to school entry or travel to endemic areas
  • After vaccination, immunity is active within ~1 week and therefore vaccination is useful as postexposure prophylaxis if given within 2 weeks of exposure
  • Vaccination is useful in event of community outbreak
  • Intramuscular IgG from pooled human plasma after exposure provides passive protection for ~6 months
Tests generally appear in the order most useful for common clinical situations. Click on number for test-specific information in the ARUP Laboratory Test Directory.

Hepatitis Panel, Acute with Reflex to HBsAg Confirmation 0020457
Method: Qualitative Chemiluminescent Immunoassay

Hepatitis A Virus Antibody, IgM 0020093
Method: Qualitative Chemiluminescent Immunoassay

Hepatitis A Virus Antibodies (Total) 0020591
Method: Qualitative Chemiluminescent Immunoassay

Limitations 

Assay detects both IgG and IgM antibodies but does not differentiate between them

Hepatic Function Panel 0020416
Method: Quantitative Enzymatic/Quantitative Spectrophotometry

Guidelines

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention (CDC). Adult Immunization Schedule. Center for Disease Control and Prevention. [Last updated Feb 2017; Accessed: Sep 2017]

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Epidemiology and Prevention of Vaccine-Preventable Diseases - Hepatitis A. Centers for Disease Control and Prevention. Atlanta, GA [Last updated May 2015; Accessed: Aug 2017]

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Manual for the Surveillance of Vaccine-Preventable Diseases. Centers for Disease Control and Prevention. Atlanta, GA [Last updated Apr 2016; Accessed: Aug 2017]

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Prevention of Hepatitis A Through Active or Passive Immunization - Recommendations of the Advisory Committee on Immunization Practices (ACIP). Centers for Disease Control and Prevention: Morbidity and Mortality Weekly Report. Atlanta, GA [Published May 2006; Accessed: Aug 2017]

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Recommended Immunization Schedules for Children and Adolescents Aged 18 Years or Younger. United States, 2016. Centers for Disease Control and Prevention. Atlanta, GA [Last Updated Jan 2017; Accessed: Sep 2017]

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Sexually Transmitted Diseases Treatment Guidelines, 2015. June 5, 2015, 64(RR3);1-137. Centers for Disease Control and Prevention. Atlanta, GA [Last updated Jun 2015; Accessed: Aug 2017]

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Update: Prevention of Hepatitis A After Exposure to Hepatitis A Virus and in International Travelers. Updated Recommendations of the Advisory Committee on Immunization Practices (ACIP). Centers for Disease Control and Prevention: Morbidity and Mortality Weekly Report. Atlanta, GA [Published Oct 2007; Accessed: Aug 2017]

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Updated Recommendations from the Advisory Committee on Immunization Practices (ACIP) for Use of Hepatitis A Vaccine in Close Contacts of Newly Arriving International Adoptees. Centers for Disease Control and Prevention: Morbidity and Mortality Weekly Report. Atlanta, GA [Published Sep 2009; Accessed: Aug 2017]

General References

Andersson KL, Friedman LS. Hepatitis a: a traveling target; comment on "the evolving epidemiology of hepatitis a in the United States". Arch Intern Med. 2010; 170(20): 1818-9. PubMed

Jeong S, Lee H. Hepatitis A: clinical manifestations and management. Intervirology. 2010; 53(1): 15-9. PubMed

Kojaoghlanian T. Hepatitis A. Pediatr Rev. 2010; 31(8): 348-50. PubMed

Matheny SC, Kingery JE. Hepatitis A. Am Fam Physician. 2012; 86(11): 1027-34; quiz 1010-2. PubMed

Nainan OV, Xia G, Vaughan G, Margolis HS. Diagnosis of hepatitis a virus infection: a molecular approach. Clin Microbiol Rev. 2006; 19(1): 63-79. PubMed

Sharapov UM, Hu DJ. Viral hepatitis A, B, and C: grown-up issues. Adolesc Med State Art Rev. 2010; 21(2): 265-86, ix. PubMed

U.S. Department of Health and Human Services, Centers for Disease Control and Prevention. Viral Hepatitis - Hepatitis A Information. Centers for Disease Control and Prevention. [Accessed: Aug 2017]

Medical Reviewers

Last Update: October 2017