HIV and AIDS: looking ahead

Abstract

Although the future of HIV science is uncertain, we need to reappraise HIV diversity, pathogenesis and immunity. The AIDS pandemic threatens the success of existing vaccine programs and may accelerate the emergence of new infectious diseases.

Figure 1. The human toll of AIDS.

(a) Comparison of annual deaths from AIDS between sub-Saharan Africa (population 640 million) and the United States (population 273 million). (b) The five leading causes of death in men and women aged 25–44 years in the United States. Over the course of 10 years, AIDS came to be the chief cause of death in this generally healthy age group. The precipitous fall in mortality followed the introduction of highly active antiretroviral therapy (HAART), although the prevalence of HIV infection has not decreased. Reproduced with permission from ref. from data provided by the Joint United Nations Programme on HIV/AIDS and the US Centers for Disease Control and Prevention. Katie Ris

Figure 2. The scale of HIV variation.

Sequence divergence of envelope glycoproteins of HIV (gp120, V2-C5) compared with that of influenza A H3 (HA1). The length of the spokes indicates the degree of divergence with the scale indicated. HIV variation in a single person 6 years after infection (9 genomes analyzed) is similar to that of worldwide influenza A (96 genomes analyzed) in a single year. The greatest degree of variation is in the Democratic Republic of Congo, where HIV first developed and has diversified into subtypes A–K (except for subtype B, prevalent in the West, and subtype E, prevalent in Thailand). Adapted with permission from ref. . Katie Ris