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Vaccine Information

Hepatitis A

Entry last updated: May 27, 2004

- Understanding the Disease
- Available Vaccines
- History of the Vaccine
- Who Should and Should Not Receive the Vaccine
- Dose Schedule
- Effectiveness of the Vaccine
- Known Side Effects
- Related Issues
- Key References and Sources of Additional Information
- State Vaccine Requirements
- Important Facts for Parents to Know
- Frequently Asked Questions
- CDC Vaccine Information Statement

Understanding the Disease

Hepatitis A infection is caused by the hepatitis A virus (HAV).

In the United States, hepatitis A is one of the most frequently reported diseases that can be prevented by a vaccine. When infected by hepatitis A virus, adolescents and adults are more likely than young children to develop signs and symptoms of disease, including fever, weakness, nausea, abdominal pain, dark urine, and yellow eyes and skin, and are more likely to experience severe disease.

Symptoms usually last less than two months, but 10% to 15% of those infected will have prolonged or relapsing disease lasting up to six months. Unlike hepatitis B and C, chronic hepatitis A disease does not occur. Unfortunately, each year in the U.S. 125,000 to 200,000 people become sick with hepatitis A, and 70 to 100 people die, mostly those with underlying liver disease.

This virus is most commonly spread in stool, although it can be spread through contact with infected blood. Outbreaks sometimes occur when many people have eaten from the same Hepatitis A-infected food source. Infected people are most likely to spread hepatitis A virus during the two-week period before they know they are infected. Since most infected pre-school children show no symptoms of hepatitis A infection, they often unknowingly spread the hepatitis A virus to others.

About one-third of the hepatitis A cases in the U.S. occur in children 5 to 14 years of age. The lowest rate of infection is in adults more than 40 years old. The rate of infection is higher in lower income populations, and the disease is more common in areas with higher populations of American Indian and Alaskan natives than in other areas of the country.

Available Vaccines

The hepatitis A vaccine is available as:

  • HAV (alone)
  • HAV in combination with hepatitis B (HBV) vaccine

Product: Havrix� (HAV)
Manufacturer: GlaxoSmithKline
Year Licensed: 1995

Product: Vaqta� (HAV)
Manufacturer: Merck
Year Licensed: 1996

Product: Twinrix� (HAV and HBV combination vaccine)
Manufacturer: GlaxoSmithKline
Year Licensed: 2001

For information on the thimerosal content in these vaccines, see the Food and Drug Administration at
or Johns Hopkins University's Institute for Vaccine Safety at

History of the Vaccine

Since 1995, more than seven million doses of a HAV vaccine have been administered in the U.S.

Who Should and Should Not Receive this Vaccine

Who should receive the vaccine?

The vaccine is recommended for:

  • Children two years of age or older who live in areas of the U.S.�where hepatitis A is common, such as the Southwest and West Coast. To be more precise, the vaccine is recommended for children in areas where 10-per-100,000 people are infected. States in this category include Arizona, Alaska, Oregon, New Mexico, Utah, Washington, Oklahoma, South Dakota, Idaho, Nevada and California.
  • People traveling to or working in countries that have high or intermediate rates of infection, such as those located in Central or South America, the Caribbean, Mexico, Asia (except Japan), Africa, and southern or eastern Europe. The vaccine series should be started at least one month before traveling.
  • Men who have sex with men
  • People who use illicit drugs
  • People who work with HAV-infected primates or HAV in a laboratory
  • People who receive clotting factor concentrates
  • People infected with other hepatitis viruses
  • People with chronic liver disease who are not already immune to HAV
  • People who have received, or are waiting to receive, a liver transplant
  • Food handlers should consider getting the HAV vaccine.
  • People aged 18 and older who are at risk for both HAV (based on the above risk factors) and HBV may receive the hepatitis A and B combination vaccine. Adults are at risk for hepatitis B virus infection if they have had more than one sex partner during a six month period; are health care workers, or are otherwise exposed to infected blood or body fluids; are men who have sex with other men; or use injection drugs.

Who should not receive the vaccine?

  • Those who have had a serious adverse reaction to a previous dose of the vaccine or its ingredients should not receive another dose.
  • People who are moderately or severely ill should consult with their physician before receiving any vaccine.
  • The safety of hepatitis A vaccine for pregnant women is not yet known. But any risk to either the pregnant woman or the fetus is thought to be very low.

This vaccine is recommended by:

  • Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention
  • American Academy of Pediatrics
  • American Academy of Family Physicians
  • American Thoracic Society

The complete childhood immunization schedule can be found at:

The summary of adolescent/adult immunization recommendations can be found at:

Dose Schedule

Hepatitis A vaccines are given in two doses. Anyone two years of age or older may receive the first dose. The timing of the second dose depends upon which manufacturer�s vaccine is administered. Though preferable, it is not necessary to receive the same manufacturer�s hepatitis A vaccine for both doses. Both hepatitis A vaccines have pediatric and adult formulations.

  • Havrix�1 (GlaxoSmithKline): The second dose should be given 6 to 12 months after the first.
  • Vaqta� (Merck): For those aged 2 to 18 years, the second dose should be given 6 to 18 months after the first. For people over 18 years, the second dose should be given 6 to 12 months after the first.
  • The hepatitis A and B combination vaccine (Twinrix�, GlaxoSmithKline) is approved for people 18 years and older and is given on a 0-, 1-, and 6-month schedule.

1 NNii uses vaccine trade names only for clarity in our presentation of immunization recommendations. NNii does not recommend specific vaccine brands over others.

Effectiveness of the Vaccine

Between 97% and 99% of healthy people two years of age or older who receive two doses of the vaccine are protected from HAV infection. Immunity usually develops within four weeks after the initial dose. After two doses of the vaccine, it is estimated that immunity will last for at least 20 years.

Researchers are working to determine how effective the Hepatitis A vaccine is at preventing the disease if it is administered after a person has already been exposed to the virus.

Known Side Effects

About half of those who receive the vaccine will have no side effects. Most others will have only a mild reaction, such as:

  • Soreness at the injection site (56% of those who get the vaccination)
  • Headache (14% of those who get the vaccination)
  • Temporary weakness (7% of those who get the vaccination)

If these problems occur, they usually come 3-5 days after vaccination and last for 1 or 2 days.

No serious adverse events have been attributed to the hepatitis A vaccine. In very rare cases a person may be allergic to some component of the vaccine (such as a preservative). Signs of allergic reaction can include difficulty breathing, hoarseness or wheezing, hives, paleness, weakness, a fast heartbeat, or dizziness.

Related Issues

Hepatitis A may be widely spread through contaminated food. In 1983, for example, 203 people became ill in a county of 7,800 in Oklahoma. Ninety-two percent of those infected had eaten at the same drive-in restaurant between two and six weeks before onset of illness.

Unlike hepatitis B, mothers infected with hepatitis A rarely transmit the disease to their newborns.

The hepatitis A and B combination vaccine has been shown to be as safe and effective as HAV and HBV vaccines given separately.

Key References and Sources of Additional Information

  • American Academy of Pediatrics, Committee on Infectious Diseases. (2003). Hepatitis A. In LK Pickering (Ed.), Red Book: Report of the Committee on Infectious Diseases (26th ed., pp. 309-318). Elk Grove Village, IL: Author.
  • Centers for Disease Control and Prevention (CDC). (1998). Hepatitis A vaccine: What you need to know. [Vaccine Information Statement (VIS)].
  • CDC. (1999). Prevention of hepatitis A through active or passive immunization: Recommendations of the Advisory Committee on Immunization Practices (ACIP). Morbidity and Mortality Weekly Report, 48(RR-12).
  • CDC. (2001). Notice to readers: FDA approval for a combined hepatitis A and B vaccine. Morbidity and Mortality Weekly Report, 50(37), 806-807.
  • CDC. (2001). Recommended childhood immunization schedule�United States, 2001 (Approved by the ACIP, AAP, and AAFP). Morbidity and Mortality Weekly Report, 49(2), 35-38, 47.
  • CDC, National Immunization Program (NIP). (2004). Hepatitis A. In Epidemiology and prevention of vaccine-preventable diseases (�The Pink Book�) ( 8th ed., pp. 191-206). Atlanta: Author.�
  • CDC, NIP. (2000). Hepatitis A. In Vaccine-preventable childhood diseases [Online fact sheet].�
  • Connor B, Phair J, Sack D, McEniry D, Hornick R, Banerjee D, Jensen E, and Kuter B. (2001). Randomized, double-blind study in healthy adults to assess the boosting effect of Vaqta or Havrix after a single dose of Havrix. Clinical Infectious Diseases, 32(3), 396-401.
  • Dagan R, Amir J, Mijalovsky A, Kalmanovitch I, Bar-Yochai A, Thoelen S, Safary A, and Ashkenazi S. (2000). Immunization against hepatitis A in the first year of life: Priming despite the presence of maternal antibody. Pediatric Infectious Disease Journal, 19(11), 1045-1052.
  • Feinstone SM and Gust ID. Hepatitis A vaccine. (1999). In SA Plotkin and WA Orenstein (Eds.), Vaccines (3rd ed., pp. 650-671). Philadelphia: W.B. Saunders Company.
  • Food and Drug Administration. (2001). New combination vaccine approved for protection against two hepatitis viruses [Press Office release to FDA personnel].�
  • Grabenstein JD. (1999). Moral considerations with certain viral vaccines. Christianity and Pharmacy, 2(2), 3-6.
  • Joines RW, Blatter M, Abraham B, Xie F, De Clercq N, Baine Y, Reisinger KS, Kuhnen A, and Parenti DL. (2001). A prospective, randomized, comparative U.S. trial of a combination hepatitis A and B vaccine (Twinrix�) with corresponding monovalent vaccines (Havrix� and Engerix-B�) in adults. Vaccine,19(32), 4710-4709.
  • National Institute of Allergy and Infectious Diseases, Division of Microbiology and Infectious Diseases. (2002). The Jordan Report 20th Anniversary: Accelerated development of vaccines 2002. Bethesda, MD: Author.�

Also see our image gallery of diseases.

Including available vaccines, history of the vaccine, who should and should not receive it, dose schedules, effectiveness, known side effects, and related issues.

Hepatitis A Vaccine State Requirements

Check to see if your state requires this vaccine.

Important Facts for Parents to Know about the Hepatitis A Vaccine

A fact sheet that gives basic information on this disease, as well as the effectiveness and possible side effects of the vaccine that can prevent it.

Frequently Asked Questions about the Hepatitis A Vaccine

A fact sheet with in-depth answers to common questions about this vaccine.

CDC Vaccine Information Statement for Hepatitis A

Information provided by the Centers for Disease Control and Prevention on specific vaccines and the diseases they can prevent. Healthcare providers are required to give these to their patients before administering a vaccine.

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