Hepatitis A is caused by an enterically transmitted RNA virus that, in older children and adults, causes typical symptoms of viral hepatitis, including anorexia, malaise, and jaundice. Young children may be asymptomatic. Fulminant hepatitis and death are rare in countries that have adequate and effective water treatment and sanitation facilities. Chronic hepatitis does not occur. Diagnosis is by antibody testing. Treatment is supportive. Vaccination and previous infection are protective.
(See also Causes of Hepatitis and Overview of Acute Viral Hepatitis.)
Hepatitis A virus (HAV) is a single-stranded RNA picornavirus. It is the most common cause of acute viral hepatitis and is particularly common among children and young adults.
In some countries, > 75% of adults have been exposed to HAV. In the US in 2018, 12,474 cases were reported, and an estimated 24,900 cases occurred (many cases are not recognized or not reported [1]). Worldwide, an estimated 1.4 million cases of hepatitis A occur each year (2).
HAV spreads primarily by fecal-oral contact and thus may occur in areas of poor hygiene. Waterborne and food-borne epidemics occur, especially in countries that do not have adequate and effective water treatment and sanitation facilities. Eating contaminated raw shellfish is sometimes responsible. Sporadic cases are also common, usually as a result of person-to-person contact.
Fecal shedding of the virus occurs before symptoms develop and usually ceases a few days after symptoms begin; thus, infectivity often has already ceased when hepatitis becomes clinically evident.
HAV has no known chronic carrier state and does not cause chronic hepatitis or cirrhosis.
General references
1. Centers for Disease Control and Prevention (CDC): Hepatitis A questions and answers for health professionals. Accessed June 8, 2022.
2. World Health Organization (WHO): Hepatitis A. Accessed June 8, 2022.
Symptoms and Signs of Hepatitis A
In children < 6 years old, 70% of hepatitis A infections are asymptomatic, and in children with symptoms, jaundice is rare. In contrast, most older children and adults have typical manifestations of viral hepatitis, including anorexia, malaise, fever, nausea, and vomiting; jaundice occurs in over 70%.
Manifestations typically resolve after about 2 months, but in some patients, symptoms continue or recur for up to 6 months. Some patients have prolonged cholestasis (cholestatic hepatitis) due to hepatitis A; cholestatic hepatitis is characterized by marked jaundice with pruritus, continued fever, weight loss, diarrhea, and malaise.
Recovery from acute hepatitis A is usually complete. Fulminant hepatitis rarely occurs.
Diagnosis of Hepatitis A
Serologic testing
In the initial diagnosis of acute hepatitis, viral hepatitis should be differentiated from other disorders causing jaundice (see figure Simplified diagnostic approach to possible acute viral hepatitis).
If acute viral hepatitis is suspected, the following tests are done to screen for hepatitis viruses A, B, and C:
IgM antibody to HAV (IgM anti-HAV)
Hepatitis B surface antigen (HBsAg)
IgM antibody to hepatitis B core (IgM anti-HBc)
Antibody to hepatitis C virus (anti-HCV) and hepatitis C RNA (HCV-RNA)
If the IgM anti-HAV test is positive, acute hepatitis A is diagnosed. The IgG antibody to HAV (IgG anti-HAV) test is done (see table Hepatitis A Serology) to help distinguish acute from prior infection. A positive IgG anti-HAV test suggests prior HAV infection or acquired immunity. There is no further testing for hepatitis A.
HAV is present in serum only during acute infection and cannot be detected by clinically available tests.
IgM antibody typically develops early in the infection and peaks about 1 to 2 weeks after the development of jaundice. It diminishes within several weeks, followed by the development of protective IgG antibody (IgG anti-HAV), which persists usually for life. Thus, IgM antibody is a marker of acute infection, whereas IgG anti-HAV indicates only previous exposure to HAV and immunity to recurrent infection.
Other tests
Liver tests are needed if not previously done; they include serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase.
Treatment of Hepatitis A
Supportive care
No treatments attenuate acute viral hepatitis, including hepatitis A. Alcohol should be avoided because it can increase liver damage. Restrictions on diet or activity, including commonly prescribed bed rest, have no scientific basis.
Viral hepatitis should be reported to the local or state health department.
Prevention of Hepatitis A
Good personal hygiene helps prevent fecal-oral transmission of hepatitis A. Barrier protection is recommended, but isolation of patients does little to prevent spread of HAV.
Spills and contaminated surfaces in the home of patients can be cleaned with dilute household bleach.
Vaccination
(See also Hepatitis A [HepA] Vaccine).
The is recommended for all children beginning at age 1 year, with a 2nd dose 6 to 18 months after the first (see Centers for Disease Control and Prevention [CDC]: Child and Adolescent Immunization Schedule by Age).
Preexposure HAV vaccination (see Adult Immunization Schedule) should be provided for adults with increased risk, including
Travelers to countries with high or intermediate HAV endemicity
Diagnostic laboratory workers
Men who have sex with men
People who use injection or noninjection illicit drugs
People with chronic liver disorders (including chronic hepatitis C) because they have an increased risk of developing fulminant hepatitis due to HAV
People who anticipate close contact with an international adoptee during the first 60 days after arrival from a country with high or intermediate HAV endemicity
People who do not have stable housing or who are homeless
Preexposure HAV prophylaxis can be considered for day-care center employees and for military personnel.
≥ 2 weeks before travel; those leaving in < 2 weeks should also be given standard immune globulin. Current evidence suggests immune globulin is necessary only for older travelers and travelers with chronic liver disease or another chronic disorder.
Postexposure prophylaxis
Postexposure prophylaxis should be given to family members and close contacts of patients with hepatitis A.
For other patients, particularly those > 75 years old, those with chronic liver disease, and immunocompromised patients, standard immune globulin (formerly immune serum globulin) prevents or decreases the severity of hepatitis A. A dose of 0.02 mL/kg IM is generally recommended, but some experts advise 0.06 mL/kg (3 to 5 mL for adults). It can be given up to 2 weeks after exposure, but the earlier, the better.
Key Points
Hepatitis A virus is the most common cause of acute viral hepatitis; it is spread by the fecal-oral route.
Children < 6 years old may be asymptomatic; older children and adults have anorexia, malaise, and jaundice.
Fulminant hepatitis is rare, and chronic hepatitis, cirrhosis, and cancer do not occur.
Treat supportively.
Routine vaccination beginning at age 1 is recommended for all.
Vaccinate people at risk (eg, travelers to endemic areas, laboratory workers), and provide postexposure prophylaxis with standard immune globulin or, for some, vaccination.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
Centers for Disease Control and Prevention (CDC): Hepatitis A questions and answers for health professionals: This resource provides an overview of hepatitis A (including diagnosis, statistics, transmission, risk factors, symptoms, and the hepatitis vaccine), as well as information about the use of immune globulin and hepatitis and international travel. Accessed June 8, 2022.
