Hepatitis A and B immunizations of individuals infected with human immunodeficiency virus.

All persons at risk for infection with human immunodeficiency virus (HIV) types 1 and 2, including men who have sex with men, those with multiple heterosexual contacts, abusers of illegal injection drugs, and persons frequently exposed to blood and blood products, are also at high risk for hepatitis A virus (HAV) and acute and chronic hepatitis B virus (HBV) infections. HIV can prolong the duration and increase the level of HAV viremia and augment HAV-related liver abnormalities. HIV also magnifies HBV viremia and the risk of HBV reactivation, chronic active HBV infection, cirrhosis, and death. Because of these concerns, hepatitis A vaccination is recommended for all HIV-positive/HAV seronegative persons, with 2 standard doses given 6 to 12 months apart. Immune response to hepatitis A vaccines is excellent, even in moderately immune-suppressed individuals. Hepatitis B vaccination is also recommended for all HIV-positive persons lacking prior immunity. However, immune reactivity to hepatitis B vaccines is frequently suboptimal in terms of patients' rate of response, antibody titer, and durability. Relatively high CD4+ T-cell counts (> or =500/mm3) and low levels of HIV viremia (<1,000 RNA genome copies/mL plasma) are necessary to ensure adequate hepatitis B vaccine response. Higher hepatitis B vaccine doses, prolongation of the vaccination schedule, or both, as prescribed for many patients with non-HIV-related immune deficiencies, may be considered initially. Revaccination should be instituted if postvaccination titers of antibodies to hepatitis B surface antigen are <10 mIU/mL (<10 IU/L). Nonresponders may also react to a subsequent vaccine course if CD4+ T-cell counts rise to 500/mm3 following institution of highly active antiretroviral therapy; vaccine adjuvant trials are under way. Universal, age-based immunization of all young and middle-aged adults appears to be the most comprehensive way of protecting all populations who are at high risk.