HIV/AIDS: Lessons from a New Disease Pandemic

The acquired immunodeficiency syndrome (AIDS) was first recognized about 25 years ago (Gottlieb et al., 1981; Masur et al., 1981; Siegal et al., 1981). The best available evidence suggests that HIV newly infected the human species about 50–100 years ago (Korber et al., 2000). It did not originate in Asia. It apparently moved to people from sub-human primates in Africa (Keele et al., 2006; Kanki, 1997). Because of different clinical presentations in different populations of people, and a long incubation period, it was more difficult to diagnose than SARS or avian influenza. As a new epidemic that originated in the era of modern medicine, it taught us many lessons about the difficulties that a new infectious disease can present. Already claiming at least 60–80 million victims, AIDS seems destined to continue as a pandemic for the foreseeable future. Drugs that control HIV replication and reverse disease progression have been developed, but none eliminate the virus from the body. Sexual transmission can be prevented by abstinence or condoms, but such measures, which prevent procreation, provide only limited value. Approaches for making a vaccine using conventional techniques have failed. Most experts believe that an effective vaccine will be made eventually, but not for at least 10–20 years. We need to learn more about the immunobiology of acute HIV infection, and about potentially protective immunoepitopes, such as conformational intermediates of the virus envelope. Until a vaccine is available, there is little or no chance that HIV can be eliminated, or even drastically reduced in prevalence. AIDS has presented scientists, political leaders, and health policy experts with unprecedented challenges.