The human immunodeficiency virus (HIV) is responsible for the complex of symptoms that characterize acquired immunodeficiency disease syndrome (AIDS). The devastating impact of this disease resides with the fact that HIV targets a particular subset of cells that play a critical role in the human immune system. These cells are called Helper T cells that carry a particular protein marker (CD4) on their cell surfaces. When an individual, infected with the HIV reaches a certain threshold in viral load, the number of CD4+ cells, circulating in the bloodstream, drops dramatically. Under these circumstances, the infected person is prone to infections of all kinds, especially opportunistic infections – infections that result from bacteria, fungi or viruses that the general population is protected against with a healthy immune system.
This disease had a devastating and profound impact on the millions of lives throughout the world and has resulted in orphaning many children in the developing world. As a direct result of the intense research into the nature of HIV, there is now a “cocktail” of medicines that greatly reduces the viral load in AIDS patients; however, these drugs are prohibitively expensive. The application of safe sex practices can reduce the probability of becoming infected in sexually active individuals, but real the hope lies in the development of an effective vaccine.
HIV is a member of a class of viruses called retroviruses. These viruses are particularly troublesome for two reasons:
•They are capable of integrating into the host’s DNA and can repeatedly re-emerge and, therefore, re-infect
•They can produce many variants through minor changes in their genetic makeup.
This latter characteristic has proved problematic in developing an effective vaccine. There has been a modicum of hope and interest, however, in phase III of the trial of a vaccine that recently enrolled more than 16,000 participants in Thailand. Although analysis of the results of this trial showed an effectiveness of only 26.4%, it seems to have provided some encouragement on the part of investigators. Jerome Kim of the Walter Reed Army Institute of Research remarked that, “We’ve taken a small step. It’s not a home run, but it opens the door to future work.”
The development of a truly effective vaccine would have enormous implications for the world in general and the millions that are at risk in particular. It would also put an abrupt halt to the spread of this horrendous disease.