Link-Gelles R, et al. - Researchers reviewed the literature data on the use of hepatitis A (HepA) vaccine in adults >40 years and existing recommendations for HepA vaccine for use as postexposure prophylaxis (PEP) in other countries. Each abstract, searched from PubMed and EMBASE from January 1, 1992-January 7, 2017 using the terms “hepatitis A vaccine” and “HAV vaccine, was read by 2 reviewers and articles were preserved if they included results (seroprotection, mean titers) within 28 days of HepA vaccine administration in adults >40 years. In older adults, particularly in the very oldest age groups, a possible diminution in the immunogenicity of HepA vaccine could be seen. In order to achieve the best possible immune response, administration of HepA vaccine as early as possible within 14 days after exposure was recommended.