Hepatitis A Information
For information on local Bay Area health clinics for Hepatitis A and B vaccinations, click here

Hepatitis A
Hepatitis A or "Infectious Hepatitis" is the most common viral hepatitis infection in the world, which can now be prevented by safe and effective hepatitis A vaccines. There were an estimated 180,000 cases in the US in 1997. Hepatitis A is a virus that attacks the liver, but unlike hepatitis B and C, it does not cause chronic infection or liver cancer or chronic liver failure. It is spread by drinking water or eating improperly cooked or raw food, particularly shellfish, contaminated with human feces from infected individuals. Feces from infected young children often without symptoms are a frequent source of person to person transmission in the community.

The infection may go unnoticed especially in children under 6 years old. In older children or adults, most develop an illness about a month after the infection. Symptoms consist of fatigue, loss of appetite, dark urine and yellowing of the eyes and skin (jaundice), and even abdominal pain and fever. The diagnosis is made by a blood test for the hepatitis A IgM antibody. Immune globulin, a preparation of antibodies may minimize the risk of the infection if it is given within 2 weeksof the exposure.

Most people with hepatitis A recover completely within two months and without long-term damage to the liver. In unusual instances, hepatitis A may cause acute liver failure and death, particularly in those with chronic liver disease such as cirrhosis or chronic hepatitis B and C. About 100 people die from acute liver failure caused by hepatitis A each year in the US. There is no specific treatment for the hepatitis A virus. During the recovery period, alcohol and drugs that further damage the liver must be avoided. After recovery, the individuals will develop immunity that will protect them from future infection. This immunity can be detected in the blood by the measurement of the hepatitis A IgG antibody.

Hepatitis A Vaccination
Routine vaccination of young children is the optimal long-term method of preventing hepatitis A. Good sanitation and hygiene, and less crowded living quarters are also important in reducing the risk of infection. All Asian and Pacific Islander Americans who frequently travel to Asia, those living on the West Coast, and those with chronic hepatitis B or other liver diseases should also be vaccinated.

The Center of Disease Control further recommends hepatitis A vaccination for the following:

  • Persons traveling to or working in countries with high or intermediate HAV endemicity, such as Southeast Asia, Mexico, South and Central America, the Caribbean and Africa
  • Persons with chronic liver disease (cirrhosis, chronic hepatitis B or C)
  • Children living in areas where rates of hepatitis A are at least twice the national average, such as the Western states including California, Arizona, Alaska, Oregon, Washington, New Mexico
  • Men who have sex with men
  • Illegal drug users
  • Outbreaks in communities with high or intermediate rates of hepatitis A
  • Persons with clotting factor disorders

Modified from: Prevention of hepatitis A through active or passive immunization: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1999; 48:1-37. Download PDF (732 kb)

Hepatitis A Vaccines
Two commercially available and licensed hepatitis A vaccines, Havrix (GlaxoSmithKline) and VAQTA (Merck), have been extensively studied in persons of all ages and shown to be safe and efficacious. The recommended vaccine schedule for both vaccines is a primary immunization followed by a second, booster dose 6-12 months later. It is projected that protective antibody levels will last for more than 20 years. Neither vaccine is licensed for use in children under 12 months of age. The safety of hepatitis A vaccine in pregnant women has not yet been confirmed, but the theoretic risk to the fetus is low. No special precautions are necessary when vaccinating immunocompromised persons.

A combined hepatitis A and hepatitis B vaccine for adults, Twinrix (GlaxoSmithKline), offers the opportunity to protect against both infections at the same time. Like the monovalent vaccines, Twinrix is highly immunogenic with low rates of adverse effects (Vaccine 1999;17:1657-1662). Twinrix is given as three doses over a 6 month period and is indicated for persons 18 years or age or older. Three injections, versus five injections using the two separate vaccines, provide protection against hepatitis A and B.

Administration Schedule and Dosing of Hepatitis A Vaccines
Patients Schedule HAVRIX VAQTA
1-18 years old 0, 6-12 months 720 Elisa units/0.5 mL 25 units/0.5 mL
Over 18 years old 0, 6- 2 months 1440 Elisa units/1 mL 50 units/1 mL

Frequently Asked Questions about Hepatitis A (from CDC web site)

Go to Physician and Patient Handbook


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