Vaccination with the full series of hepatitis A vaccine (HepA) is the best way to prevent HAV infection. Immune globulin (IG) also can be used for short-term protection in certain situations.
Ask the Experts: Hepatitis A: Vaccine Recommendations
|Recommended dosages and schedules of hepatitis A vaccines|
|Vaccine||Age group||Dose||Volume||# Doses||Schedule|
|1–18 years||720 El.U.*||0.5 ml||2||0, 6–12 mos.|
|19 years and older||1440 El.U.*||1.0 ml||2||0, 6–12 mos.|
(Merck & Co.)
|1–18 years||25 U**||0.5 ml||2||0, 6–18 mos.|
|19 years and older||50 U**||1.0 ml||2||0, 6–18 mos.|
*El.U. = Elisa Units **U = Units
|Combination vaccine using hepatitis A and hepatitis B vaccines|
|Vaccine||Age group||Antigens used||Volume||# Doses||Schedule|
|18 years and older||Havrix (720 El.U.)
Engerix-B (20 mcg)
|1.0 ml||3||0, 1, 6 mos.|
|4||0, 7, 21-30 days, 12 months**|
** Accelerated schedule may be used for rapid protection prior to travel or for rapid protection of an unexposed but at-risk person who also would benefit from hepatitis B protection. Twinrix is not recommended for use as post-exposure prophylaxis.
Yes, a number of studies indicate that the two brands of HepA, Havrix (GSK) and Vaqta (Merck), are interchangeable.
For detailed information about any vaccine shortage, go to CDC’s website at www.cdc.gov/vaccines/hcp/clinical-resources/shortages.html.
The Advisory Committee on Immunization Practices (ACIP) recommends routine HepA vaccination for the following groups:
- All children at age 1 year (12–23 months)
- All children and adolescents age 2 through 18 years who have not previously received HepA should be vaccinated (i.e., routine catch-up vaccination)
- People living with HIV infection
- Travelers age 12 months and older to areas of the world with intermediate or high hepatitis A virus (HAV) endemicity. Low endemicity regions include the United States, Canada, Western Europe, Japan, New Zealand, and Australia. For more information, see the CDC travel health website for current information about specific countries at https://wwwnc.cdc.gov/travel or the CDC Yellow Book. (wwwnc.cdc.gov/travel/yellowbook/2020/travel-related-infectious-diseases/hepatitis-a). When in doubt, vaccinate.
- Infants age 6 through 11 months traveling outside the United States should receive 1 dose when protection against HAV infection is recommended. The travel dose does not count toward the routine HepA series which should be initiated at age 1 year with the appropriate dose and schedule. In these instances, the child will receive a total of 3 doses of HepA vaccine.
- Men who have sex with men
- Users of illegal drugs, injectable or noninjectable
- People who are homeless or in unstable living arrangements, including shelters
- Previously unvaccinated people who anticipate having close personal contact with an international adoptee from a country of high or intermediate endemicity during the first 60 days following the adoptee’s arrival in the U.S.
- People who work with HAV-infected nonhuman primates or with HAV in a research laboratory setting
- People with chronic liver disease (including but not limited to people with hepatitis B infection, hepatitis C infection, cirrhosis, fatty liver disease, alcoholic liver disease, autoimmune hepatitis, or an ALT or AST level persistently greater than twice the upper limit of normal)
- People identified during pregnancy to be at risk for HAV infection due to presence of a specific risk factor for exposure or at risk for severe outcome from HAV infection (for example, those with chronic liver disease or with HIV infection).
- During an outbreak, any unvaccinated person who is identified as at risk for HAV infection or at risk for severe disease from HAV
- Any person who wishes to be immune to hepatitis A
HepA vaccination is not routinely recommended for healthcare personnel, food handlers, sewage workers, or day care providers because there is no evidence that their occupational risks of HAV exposure are significantly higher than the general population. However, any person who desires protection from HAV infection may be vaccinated.
For details about CDC recommendations for the prevention of hepatitis A, see the 2020 recommendations of the Advisory Committee on Immunization Practices (ACIP): www.cdc.gov/mmwr/volumes/69/rr/pdfs/rr6905a1-H.pdf.
- [added] All children ages 2 through 18 years not previously vaccinated
- [added] All people age 1 year or older living with HIV infection
- [added] People identified to be at risk for HAV infection during pregnancy
- [removed] People with clotting factor disorders
Yes, unless the person is allergic to any of the vaccine components. HepA vaccination is safe and effective and is recommended for any person who wishes to obtain immunity.
All children should receive 2 doses of HepA vaccine beginning at age 1 year (i.e., 12–23 months). The 2 doses in the series should be administered at least 6 months apart. Any child age 2 through 18 years not previously vaccinated should be vaccinated. For a copy of the ACIP recommendations on hepatitis A, go to www.cdc.gov/mmwr/volumes/69/rr/pdfs/rr6905a1-H.pdf.
No. The minimum interval between dose #1 and #2 of HepA vaccine is 6 calendar months, not 24 weeks.
Yes. The second dose was given more than 4 days before the minimum interval of 6 calendar months, so it is considered invalid and should be repeated. The repeat dose should be administered the proper minimum interval (6 months) after the invalid dose. If this repeat dose is inadvertently given less than 6 months after the invalid dose, it does not need to be repeated again as long as the interval between the initial HepA vaccine and the most recent dose is at least 6 calendar months.
In 2020, CDC published revised recommendations for hepatitis A postexposure prophylaxis (PEP). Please see the complete PEP recommendations at www.cdc.gov/mmwr/volumes/69/rr/pdfs/rr6905a1-H.pdf, with special attention to Table 4 on page 19 and Appendix B: Provider Guidance on Risk Assessment for Hepatitis A Postexposure Prophylaxis, beginning on page 36.
Healthy people who have completed the HepA vaccination series at any time do not need additional PEP if they are exposed to HAV. People who have recently been exposed to HAV and who have not received HepA vaccine previously should receive PEP as soon as possible, within 2 weeks of exposure.
People age 12 months and older exposed to HAV within the past 14 days and who have not previously completed the HepA vaccine series should receive a single dose of HepA vaccine as soon as possible. In addition to vaccine, immune globulin (IG; 0.1 mL/kg) may be administered to people older than age 40 years depending on the providers’ risk assessment. For long-term immunity, the HepA vaccine series should be completed with a second dose at least 6 months after the first dose. However, the second dose is not necessary for PEP. A second dose should not be administered sooner than 6 calendar months after the first dose, regardless of HAV exposure risk.
People age 12 months or older who are immunocompromised or have chronic liver disease, and who have been exposed to HAV within the past 14 days and have not previously completed the HepA vaccination series, should receive both IG (0.1 mL/kg) and HepA vaccine at the same visit in a different anatomic site (for example, separate limbs) as soon as possible after exposure. For long-term immunity, the HepA vaccination series should be completed with a second dose at least 6 months after the first dose. However, the second dose is not necessary for PEP. A second dose should not be administered sooner than 6 calendar months after the first dose, regardless of HAV exposure risk.
People with HIV infection develop protective levels of antibody more slowly and are less likely to develop protective antibody levels after vaccination with HepA, especially if their CD4+ count is low at the time of vaccination. Protection following vaccination of a person with HIV may wane over time. Vaccine should be administered if the exposed individual is not fully vaccinated; however, CDC also advises clinicians to consider administering IG PEP to an individual with HIV after a high-risk exposure (such as a household or sexual contact) even if the individual has been fully vaccinated.
Twinrix contains half the amount of hepatitis A antigen as a standard single-dose adult HepA vaccine. Twinrix should not be used for PEP but may be used to confer protection to at-risk but not yet exposed persons during an outbreak.
Infants younger than age 12 months and persons for whom vaccine is contraindicated should receive IG (0.1 mL/kg) instead of HepA vaccine as soon as possible and within 2 weeks of exposure. MMR and varicella vaccines should not be administered sooner than 6 months after IG administration in order to avoid possible IG interference with the effectiveness of MMR and varicella vaccines.
Prevaccination serologic testing for HAV (measuring either total anti-HAV or IgG anti-HAV) is not indicated for children because of the low prevalence of infection in children. It also is not routinely recommended for adults but may be considered in some settings to reduce costs associated with vaccinating people who are already immune. Prevaccination testing should not be used if it poses a barrier to vaccinating susceptible people, especially people who are difficult to access.
Prevaccination testing is most likely to be cost-effective for adults who were either born in or lived for long periods of time in areas of the world with high or intermediate hepatitis A endemicity. When evaluating people from populations with high rates of previous HAV infection, vaccination history also should be obtained, if feasible. If testing or vaccination history is not available, do not postpone vaccinating. There is no harm in vaccinating a person who has had natural infection or previous doses of vaccine.
Serologic testing for immunity to hepatitis A virus (HAV) is not necessary after routine HepA vaccination of infants, children or adults. Testing for the presence of anti-HAV antibody one month or more after completing the HepA vaccination series is recommended only for people whose future clinical management depends on knowing their immune status and for whom revaccination might be indicated, such as people living with HIV and other immunocompromised persons (such as transplant recipients and people vaccinated while receiving chemotherapy). In such individuals, if the results of postvaccination testing do not show an adequate immune response (10 mIU/mL or higher), revaccination with a complete series is recommended, followed by a second postvaccination serologic test. If that second test remains negative, no additional vaccination is recommended; however, the patient should be counseled on strategies to avoid exposure to HAV and the need for IG if an exposure occurs. If vaccination results in seroconversion, insufficient data are available to make recommendations concerning repeat testing, booster doses or revaccination.