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Interim outbreak-specific guidance on hepatitis A vaccine administration

Hepatitis A vaccine administration recommendations and guidelines are published by the Advisory Committee on Immunization Practices (ACIP):

Consistent with these recommendations and guidance, in the current multistate hepatitis A virus outbreak, the following can also be considered:

  1. Use of TWINRIX® for pre- and post-exposure prophylaxis [PDF – 14 pages]
    TWINRIX® is licensed for use in persons aged >18 years and is a combined hepatitis A (HAVRIX) and hepatitis B vaccine (ENGERIX-B®) and may be appropriate for use in the context of constrained supplies of single antigen adult Hepatitis A vaccine as detailed below.

    Pre-exposure prophylaxis:
    After 3 doses of TWINRIX®, antibody responses to both antigens are equivalent to responses seen after the single antigen vaccines are administered separately on standard schedules. Seroconversion (defined as equal to or greater than the assay cut-off depending on assay used) for antibodies against HAV was elicited in 93.8%, 98.8% and 99.9% of vaccinees after 1, 2 and 3 doses of TWINRIX, respectively. Protective antibodies (defined as ≥10 mIU/mL) against HBV surface antigen were detected in 30.8%, 78.2% and 98.5% of vaccinees after 1, 2 and 3 doses of TWINRIX, respectively. Those rates are available available in the package insert linked above and are displayed here:

    Seroconversion and Seroprotection
    Rates in Worldwide Clinical Trials
    TWINRIX Dose
    N % Seroconversion
    for Hepatitis Aa
    % Seroprotection
    for Hepatitis Bb
    1 1,587 93.8 30.8
    2 1,571 98.8 78.2
    3 1,551 99.9 98.5

    aAnti-HAV titer ≥assay cut-off: 20 mIU/mL (HAVAB Test) or 33 mIU/mL (ENZYMUN-TEST®).
    bAnti-HBsAg titer ≥10 mIU/mL (AUSAB® Test).

    If TWINRIX® is given to unexposed persons during an outbreak, vaccinators should ensure that vaccinated persons know the  importance of receiving all vaccine doses needed to get maximum protection from hepatitis A and B vaccination as indicated in the seroconversion and seroprotection rates.

    Post-exposure prophylaxis:

    TWINRIX® contains 720 EL.U. of hepatitis A antigen, which is half of the HAVRIX® adult dose. No data are available for the use of TWINRIX® for post-exposure prophylaxis, and therefore it is not recommended for post-exposure prophylaxis.

  2. Use of pediatric vs. adult formulations of hepatitis A vaccine

    VAQTA® is licensed in two formulations, which differ according to the person’s age. Persons aged 12 months–18 years should receive 25 U per dose in a 2-dose schedule; persons aged >18 years should receive 50 U per dose in a 2-dose schedule. VAQTA® (manufactured by Merck & Co., Inc)[PDF – 18 pages]

    HAVRIX® is available in two formulations, which differ according to the person’s age: for persons aged 12 months–18 years, 720 EL.U. per dose in a 2-dose schedule; and for persons aged >18 years, 1,440 EL.U. per dose in a 2-dose schedule. HAVRIX® (manufactured by GlaxoSmithKline)[PDF – 16 pages]

    Administering 2-doses of 25 U VAQTA® or 2-doses of 720 EL.U. HAVRIX® to persons aged >18 years in place of one adult dose is not an ACIP recommendation and is not included as a method for dosage and administration in the manufacturers’ package inserts.  Hepatitis A vaccines should be administered in the age-appropriate doses.

  3. Use of one dose of hepatitis A vaccination

    To conserve vaccine supply and maximize the availability of at least one dose of hepatitis A vaccine among persons with hepatitis A exposure risk, the second dose of hepatitis A vaccine can be deferred until supply is secured. Protective anti-hepatitis A virus antibody levels after a single dose of inactivated hepatitis A vaccine can persist for at least 14 years.1 In addition, a single dose of this vaccine has been shown to successfully control outbreaks of hepatitis A.2

    [1] Ott JJ, Wiersma ST. Single-dose administration of inactivated hepatitis A vaccination in the context of hepatitis A vaccine recommendations. Int J Infect Dis. 2013 Nov;17(11):e939-44. doi: 10.1016/j.ijid.2013.04.012. Epub 2013 Jun 21. Review. PubMed PMID: 23791857.

    [2] McMahon BJ, Beller M, Williams J, Schloss M, Tanttila H, Bulkow L. A program to control an outbreak of hepatitis A in Alaska by using an inactivated hepatitis A vaccine. Arch Pediatr Adolesc Med. 1996 Jul;150(7):733-9. PubMed PMID: 8673200.

  4. Pre-vaccination serological testing

    In populations that are expected to have high rates of previous HAV infection, vaccination history should be obtained where feasible, and pre-vaccination testing may be considered to reduce costs by not vaccinating persons who are already immune.

    Testing of children is not indicated because they are expected to have low prevalence of infection; however, vaccination history should be obtained when feasible.

    For adults, the decision to test should be based on 1) the expected prevalence of immunity, 2) the cost of vaccination compared with the cost of serologic testing (including the cost of an additional health care visit), and 3) history of previous hepatitis A vaccination if known, and 4) the likelihood that testing will not interfere with initiation of vaccination. For example, when feasible pre-vaccination testing of adults should be considered in certain populations that have a high prevalence of infection (e.g., injection drug users, MSM, inmates in correctional facilities).* [PDF – 30 pages]

    Pre-vaccination testing should not be considered in an outbreak setting when the vaccine is used for post-exposure prophylaxis after a known exposure with a narrow window for administration. When TWINRIX® is administered for pre-exposure prophylaxis, pre-vaccination testing for hepatitis A and hepatitis B can be considered.

    *Bryan JP, Nelson M. Testing for antibody to hepatitis A to decrease the cost of hepatitis A prophylaxis with immune globulin or hepatitis A vaccines. Arch Intern Med 1994;154:663–8.