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What is Hepatitis A?Updated 6-6-24
  • Hepatitis A virus (HAV) can cause a liver infection that usually resolves on its own, but in rare occasions, it can cause long term liver disease.
  • The virus is found in the stool and blood of persons who are infected. It is spread by eating contaminated food or through contact with an infected person.
  • Persons with hepatitis A can spread the virus to others up to 2 weeks before symptoms appear.
  • The best way to protect against Hepatitis A is vaccination. Hepatitis A can also be prevented by practicing good hand hygiene after using the bathroom and before preparing or eating food.
  • More information about hepatitis A is available here.
Hepatitis A: Symptoms and Complications
  • Symptoms of Hepatitis A occur 2 to 7 weeks after infection and include:
    • Fatigue
    • Nausea or vomiting
    • Diarrhea
    • Fever and chills
    • Dark urine
    • Light stools
    • Yellow of the eyes and skin (jaundice)
    • Poor appetite
    • Joint pain
  • Adults are more likely to have symptoms than children.
  • Symptoms usually last less than 2 months, although some people can be ill for as long as 6 months.
  • Children with the virus often don’t have symptoms, but they often pass the disease to others, including their unvaccinated parents or caregivers.

If you think you may have been exposed to or infected with hepatitis A, talk with your provider.

Information for the Public
Vaccine Information
  • Vaccination is the best way to be protected against hepatitis A.
  • The hepatitis A only vaccines (Vaqta or Havarix) are 2 doses given 6 months apart. Both shots are needed for long-term protection against hepatitis A.
  • A combination hepatitis A and B vaccine (Twinrix) is also available for adults aged ≥18 years. Twinrix is a 3 dose series given over 6 months. Twinrix can also be given as a 4 doses series at an accelerated schedule.
  • Nearly 100% of healthy individuals will develop long lasting immunity against hepatitis A after completing the vaccine series. This immunity can last for at least 20 years and in many cases, it can last a lifetime.
Vaccine Recommendations

The hepatitis A vaccine protects infants, children, and adults from hepatitis A. These vaccines are routinely provided during the primary infant vaccination series. The vaccine is recommended for adolescents and adults at high risk of infection or severe disease as described below, as well as anyone seeking protection.

Who SHOULD get the vaccine:

The Advisory Committee on Immunization Practices (ACIP) recommends that the following people should receive hepatitis A vaccination:

Children

  • All children aged 12–23 months
  • Unvaccinated children and adolescents 2–18 years of age

People at increased risk for getting infected

  • International travelers
  • Men who have sex with men
  • People who use or inject illicit drugs
  • People who work with hepatitis A (such as in a laboratory setting)
  • People who work closely with people who are increased risk for getting hepatitis A
  • People who anticipate close contact with an international adoptee
  • Persons experiencing homelessness

People at increased risk for severe disease from HAV infection

  • People with chronic or long-term liver diseases (including hepatitis B and C)
  • Persons living with HIV
  • Immunocompromised
  • Age (>40 years)

Who should NOT get the vaccine (if applicable):

  • People who ever had a life-threatening allergic reaction to the hepatitis A vaccine or known to be allergic to any part of the hepatitis A vaccine.
Where to get the Vaccine

There are many places to get the hepatitis A vaccine. If you have insurance, talk to your doctor or check with your local pharmacy to see what vaccines are offered. Most health insurances cover the cost of all recommended vaccines for children and adults.

If you are uninsured or underinsured, there are programs available to help cover the cost of vaccines. Children who are 18 years of age or younger are eligible to receive vaccines at no cost through the Vaccines for Children (VFC) Program if they are:

  • Eligible for or are enrolled in Medi-Cal
  • American Indian or Alaskan Native
  • Uninsured (do not have health insurance)
  • Underinsured (private health insurance does not cover the full cost of vaccines)

Click to see if your child is eligible to receive VFC vaccines: English | Spanish

Uninsured or underinsured adults can access free or low cost vaccines at select clinics enrolled in the Vaccines for Adults (VFA) program. For more information on who is eligible, read VFA Eligibility Based on Insurance Status. You can use the following resources for more information on locating clinics:

You can also dial 2-1-1 for a list of free or low cost vaccine clinics. This includes Vaccines for Children (VFC) provider locations that serve Medi-Cal eligible children and uninsured or underinsured adults. Learn more about specific vaccine information for different age groups:

Keeping Record of Your Immunization Records

Are you not sure if you have been vaccinated against hepatitis A or you can’t find your vaccine records?

If you need official copies of your vaccine records, or if you need to update your personal records:

Additional Resources
Information for Providers
Clinical Presentation
  • The onset of an acute hepatitis A infection is usually abrupt with fever, headache, malaise, anorexia, nausea, vomiting, diarrhea and abdominal discomfort, which may be followed by jaundice.
  • Clinical criteria include:
    • Presence of a discrete onset of clinical symptoms (see above) AND,
    • Jaundice or elevated total bilirubin levels > 3.0 mg/dL, or b) ALT >200 IU/L, AND,
    • Absence of a more likely diagnosis
  • In children younger than aged 6 years, most (70%) infections are asymptomatic. In older children and adults, infection is usually symptomatic, with jaundice occurring in more than 70% of patients.
Vaccine Recommendations
  • Three vaccines are licensed in the United States to prevent hepatitis A infection (see Table 1).
    • Vaqta
    • Havarix
    • Twinrix (Combination Hepatitis A and Hepatitis B vaccine)
  • CDC recommends routine hepatitis A vaccination for children aged 12 – 23 months and all children and adolescents aged 2 – 18 years who have not been previously vaccinated.
  • Additionally, routine vaccination is recommended for adults at increased risk for HAV infection, or who are at increased risk for severe disease from HAV infection.
  • Administer Hep A vaccine to infants aged 6 -11 months traveling outside of the United States. The travel-related dose should not be counted toward the routine 2-dose series. The 2-dose Hepatitis A vaccination series should be initiated at age 12 months according to the routine, age-appropriate vaccination schedule.
  • Twinrix, a combination Hepatitis A and B vaccine, is available for persons aged 18 years and older. Twinrix is not recommended for post-exposure prophylaxis.
  • Both monovalent Hepatitis A vaccines are highly immunogenic. More than 95% of adults will develop protective antibody within 4 weeks of a single dose of either vaccine, and nearly 100% will seroconvert after receiving 2 doses. More than 97% of children and adolescents will be seropositive within a month of the first dose.

Table 1: Hepatitis A Vaccines

Trade Name
(manufacturer)		 Age group (yrs) Dosage Route Number of Doses
& Schedule		 Booster
Havrix
(GlaxoSmithKline)		 1-18 0.5 mL IM 2 doses at 0, 6-12 months None
≥19 1 mL IM 2 doses at 0, 6-12 months None
Vaqta
(Merck)		 1-18 0.5 mL IM 2 doses at 0, 6-18 months None
≥19 1 mL IM 2 doses at 0, 6-18 months None
Twinrix*
(GlaxoSmithKline)		 ≥18 (primary) 1 mL IM 3 doses at 0, 1, 6 months None
≥18 (accelerated schedule) 1 mL IM 3 doses at 0, 7, 21-30 days 12 months

*Twinrix is not recommended for post – exposure prophylaxis.

Pre-exposure and Post-exposure Prophylaxis

Pre-exposure prophylaxis — The primary tool for protection against hepatitis A prior to exposure is vaccination, which is superior to immune globulin with respect to achievable antibody concentrations and durability of immune response. Administration of immune globulin is warranted for selected nonimmune individuals at risk for hepatitis A exposure. Indications for each of these interventions are outlined in Table 2.

Post-exposure prophylaxis to individuals exposed to HAV consists of hepatitis A vaccine and/or immune globulin, depending on the patient characteristics.

Table 2: Recommendations for postexposure prophylaxis and preexposure protection, by age group and risk category Indication/Age Group Risk category/Health Status Hepatitis A vaccine Immune globulin
Postexposure prophylaxis
<12 months Healthy No 0.1mL/kg
12 months-40 years Healthy 1 dose† None
>40 years Healthy 1 dose† 0.1 mL/kg§
≥12 months Immunocompromised or chronic liver disease 1 dose† 0.1 mL/kg
≥12 months Vaccine contraindicated** No 0.1 mL/kg
Preexposure protection
<6 months Healthy No 0.1–0.2 mL/kg§§
6-11 months Healthy 1 dose¶¶ None
12 months-40 years Healthy 1 dose*** None
>40 years Healthy 1 dose*** 0.1–0.2 mL/kg§§,†††
All ages Immunocompromised or chronic liver disease 1 dose*** 0.1–0.2 mL/kg§§,†††
>6 months Persons who elect not to receive vaccine or for whom vaccine is contraindicated** No 0.1–0.2 mL/kg§§

* Measles, mumps, and rubella vaccine should not be administered for at least 2 weeks before and 6 months after administration of IG.
† A second dose of HepA vaccine is not required for postexposure prophylaxis; however, for long-term immunity, the vaccination series should be completed with a second dose at least 6 months after the first dose.
§ The provider's risk assessment should determine the need for IG administration. If the provider's risk assessment determines that both vaccine and IG are warranted, hepatitis A vaccine and IG should be administered simultaneously in a different anatomic site (eg, separate limbs).
¶ Vaccine and IG should be administered simultaneously in a different anatomic site (eg, separate limbs).
** Life-threatening allergic reaction to a previous dose of hepatitis A vaccine or allergy to any vaccine component.
†† IG should be considered before travel for persons with special risk factors for either HAV infection or severe disease from HAV infection.
§§ 0.1 mL/kg for travel up to 1 month; 0.2 mL/kg for travel up to 2 months, 0.2mL/kg every 2 months for travel of ≥2 months' duration.
¶¶This dose should not be counted toward the routine 2-dose series, which should be initiated at age 12 months.
*** For persons not previously vaccinated with hepatitis A vaccine, administer dose as soon as travel is considered, and complete series according to routine schedule if the next dose is needed before travel.
††† May be administered based on provider's risk assessment.

Please contact the Acute Communicable Disease Control (ACDC) Program to report a case, obtain any other technical assistance with specimen collection or completion of forms for hepatitis A.  



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    • Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.

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