HIV Infections: The Global Epidemiology and Goals for Vaccine Research

By mid-1998, more than 30 million people worldwide were living with the human immunodeficiency virus (HIV), with about 5 million of those infected just that year. In the two decades of the HIV epidemic, it has been estimated that over 47 million people were infected with the virus and that nearly 14 million have already died. The epidemic continues to expand, with an estimated doubling time of 10 years. Indeed, the acquired immunodeficiency syndrome (AIDS) has now surpassed tuberculosis and malaria, becoming the leading infectious cause of death. However, patterns of HIV infection and disease are changing. HIV is lowering life expectancy, while reversing previous gains in child survival in east and central Africa, and widespread heterosexual HIV transmission is emerging in parts of southern Africa and southeast Asia. Conversely, AIDS mortality has fallen in industrialized countries, but the prevalence of HIV infection and cost of treatment are increasing ( 1 ). The availability of new, effective combinations of anti-retroviral drugs is modifying the course of HIV disease, rendering the interpretation of epidemic trends difficult. Despite the fact that successes have been achieved in treating this disease, access to expensive therapies is only possible in the wealthiest nations. The treatments are difficult to administer and commonly fail, thus making prevention strategies of paramount importance for controlling the spread of this deadly virus.