Immunogenicity of Hepatitis A Vaccine Investigated in Older Patients
A recent literature review determined that hepatitis A (HepA) vaccine immunogenicity may decrease in older adult patients and that the best possible immune response is elicited when vaccine administration occurs as soon as possible within 14 days post-exposure.
PubMed and EMBASE were utilized to search for articles discussing the use of the HepA vaccine in patients >40 years old as well as for recommendations surrounding its use as postexposure prophylaxis (PEP) in other countries. The terms “hepatitis A vaccine*” and “HAV vaccine*” were searched in the databases, between January 1, 1992, and January 7, 2017. Each abstract was reviewed and only articles reporting results occurring within 28 days of vaccine administration in patients >40 years old were retained. PEP recommendations attained from 6 jurisdictions were also reviewed.
Of the total 1039 articles identified, 10 were retained and analyzed. Three of these studies directly compared patients >40 years old to patients ≤40 years old. Additionally, one study analyzed patients >40 years old in 3 separate age groups and determined immunogenicity was the lowest in the oldest patients.
"All found higher proportions seroprotected (definition varied by study) in younger age groups (ages varied by study) at 15 days post-vaccination but similar seroprotection at 30 days," the study authors reported. They added, "Most other jurisdictions reviewed recommended vaccine alone or in conjunction with immune globulin for PEP in older adults."
The results of this literature review determined that a diminished immunogenicity of the HepA vaccine may occur in older adult patients. Additionally, the vaccine elicits the best immune response when administered as soon as possible within 14 days post exposure.Reference
Link-Gelles R, Hofmeister MG, Nelson NP. Use of hepatitis A vaccine for post-exposure prophylaxis in individuals over 40 years of age: A systematic review of published studies and recommendations for vaccine use. Vaccine. In print.