Impact of HIV co-infection on hepatitis B prevention and control: a view from sub-Saharan Africa

Abstract

Human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infections are both endemic in sub-Saharan Africa, warranting high priority efforts in prevention and control. In developed countries, both viruses are transmitted more or less at the same time, and primarily in teenagers and adults. Because the two viruses share major risk factors, a number of HIV-infected individuals will either have past exposure to, or be chronic carriers of HBV. In contrast, HBV is predominantly transmitted in childhood in sub-Saharan Africa; and the majority of inhabitants are already exposed to, or are chronic carriers of HBV by the time they become exposed to HIV for the first time. Nevertheless, there is frequent detection of HBV in HIV-infected individuals (and vice versa) in the region because both viruses are highly endemic. Although there is a limited number of data on the interaction of HIV and HBV in coinfected persons in the sub-Saharan region, reports from around the world have convincingly demonstrated that HIV co-infection can have a negative impact on the transmission, natural history, prevention and control, and treatment of HBV. The impact of HIV co-infection on HBV prevention and control includes, but is not limited to: increased prevalence of HBV in HIV-infected persons; increased HBV infectivity and transmission; accelerated need for HBV therapy due to rapid progression to active chronic hepatitis B; limitation in the choice of drugs (where possible, drugs causing cross-reactivity are avoided in highly active antiretroviral therapy (HAART) regimens until there is a need to treat both viral infections), particularly in the phase of expanding HAART programmes in the region; the need to perform HBV DNA testing in HBsAg-negative sera due to frequent detection of occult hepatitis B in HIV-co-infected persons; and finally, the need for administering additional hepatitis B vaccine doses and ascertaining levels of protective anti-HBs (antibodies against HBsAg) following hepatitis B vaccination.