Hepatitis A vaccination among human immuno- deficiency virus (HIV)-infected adults: Current evidence and unanswered questions

Abstract

Hepatitis A virus (HAV) infection is common, can cause significant morbidity and mortality, and the prevalence may be higher in populations infected or at risk for human immunodeficiency virus (HIV). Immunization with HAV vaccine is recommended for HIV-infected individuals, particularly men who have sex with men, injection drug users, hemophiliacs, those with chronic liver disease, and international travelers without immunity to HAV. HAV vaccination is well-tolerated among HIV-infected individuals and is immunogenic, particularly among those with higher CD4+ cell counts. HIV-infected individuals have lower seroconversion rates and antibody concentrations in response to vaccination. However, protection against HAV as measured by HAV antibody levels is achieved for most cases. Adverse event rates are similar among those with and without HIV infection, and HAV vaccine does not have a marked impact on HIV-1 ribonucleic acid (RNA) levels, progression to acquired immune deficiency syndrome (AIDS), or CD4+ cell counts. Areas of controversy remain, including timing of vaccination relative to initiation of antiretroviral therapy, rate and impact of antibody decline over time, need for booster immunizations, and the benefit of follow-up antibody titer monitoring. Key words: Hepatitis A virus, human immunodeficiency virus (HIV), vaccination, vaccine.