The Advisory Committee on Immunization Practices Hepatitis Vaccines Work Group conducted a systematic review of evidence for the administration of post-exposure vaccine prophylaxis for hepatitis A in individuals age >40, as well as for pre-exposure prophylaxis in infants prior to travel to regions endemic for hepatitis. The Committee subsequently issued updated recommendations superseding the previous recommendations, according to a Morbidity and Mortality Weekly Report issued by the United States Centers for Disease Control and Prevention (CDC).
Infection with Hepatitis A is effectively prevented with either vaccination or immune globulin administration prior to travel to endemic regions or post-exposure prophylaxis (PEP) administered within 2 weeks of exposure in individuals age 1 to 40. However, the efficacy of vaccination or immune globulin administration >2 weeks after exposure to the virus in individuals outside the 1 to 40 age range have not been established. The updated report provides additional guidance in these areas.
From November 2016 to February 2018, the Advisory Committee on Immunization Practices Hepatitis Vaccines Work Group held monthly conference calls to review relevant scientific evidence regarding emerging applications for the hepatitis A vaccine and immunoglobulin.
The Committee noted that a randomized double blind clinical trial of hepatitis A vaccine in susceptible individuals age 2 to 40 suggested that administration of the vaccine within 2 weeks of exposure demonstrated comparable immune response to a healthy cohort in the same age range. Limited data represented a similarly comparable immune response in individuals age >40, citing evidence determined to be GRADE quality type 4 for benefits and type 3 for harms. In addition, the hepatitis A vaccine demonstrated safety and efficacy in infants age >2 months, although the investigators noted that infants <12 months may demonstrate a suboptimal immune response as a result of passively acquired maternal antibodies, which may decrease long-term immunity.
The recommendations for post-exposure prophylaxis against hepatitis A infection were updated in 2017 to include an increased dosage of immune globulin for post-exposure prophylaxis of 0.1 ml/kg. In addition, in individuals age <12 months or with a contraindication to receiving the hepatitis A vaccine should receive 0.1 mL/kg dose of immune globulin as soon as possible and within 2 weeks of exposure. The Committee noted that in infants scheduled to receive their measles, mumps, and rubella (MMR) vaccine, the vaccine should be administered preferentially to the hepatitis A vaccine; the MMR vaccine should not be administered earlier than 3 months after the immune globulin for hepatitis A. Immunocompetent individuals age >12 months who have never been vaccinated for hepatitis A should receive a single-dose hepatitis A vaccination and immune globulin simultaneously in different anatomic sites as soon as possible. In individuals age >40, the addition of immune globulin may be considered at the physician’s discretion based on risk assessment.
The Committee also made recommendations for pre-exposure prophylaxis for hepatitis A vaccination in infants age 6 to 11 months; this dose should not be counted toward the routine 2-dose series that should be initiated at age 12 months. In addition, travelers age <6 months and ≥12 months should receive an updated dosage of immune globulin when applicable (for travel duration up to 1 month, 0.1 mL/kg; for travel up to 2 months, 0.2 mL/kg; and for travel of ≥2 months, a 0.2 mL/kg dose should be repeated every 2 months for the duration of travel). For all travelers age <6 months and individuals who elect not to receive the vaccine or who have a contraindication to receiving the vaccine, it is recommended that a single dose of immune globulin be given prior to travel. Individuals age >40, who are immunocompromised, and who have chronic liver disease who are planning to travel to regions of intermediate to high hepatitis A indemnity, the recommendation is to administer the initial dose of the vaccine plus immune globulin administered in a separate anatomic site at least 2 weeks prior to travel.
In healthy individuals age 12 months to 40 years who are planning to travel to regions with endemic hepatitis A, the continued recommendation remains the administration of a single dose of the hepatitis vaccine and to complete the series according to the routine schedule.
Nelson N, Link-Gelles R, Hofmeister M, et al. Update: recommendations of the advisory committee on immunization practices for use of hepatitis A vaccine for postexposure prophylaxis and for preexposure prophylaxis for international travel. MMWR. 67(43);1216-1220.