Why HIV Vaccines and Medicines are Yet to be Found
HIV/AIDS is a continuum of conditions that are caused by infection brought about by human immunodeficiency virus. Since the 1980s when HIV was discovered, much has been done to find a vaccine but very little has been achieved. Almost 50 years down the line since the discovery, a truthfully preventive vaccine is evidently still several years’ back. The researchers who were optimistic previously about finding a cure or vaccine have in the last decades tempered with their optimism. This hub attempts to establish the reasons why making a vaccine for HIV/AIDS remains to be problematic to date.
To begin with, vaccines help a person’s immune system to recognize a particular harmful organism then fight off the disease when the body faces the actual thing. Notwithstanding extraordinary progresses in understanding both the immune system of human and HIV, a fully fruitful HIV vaccine continues to dodge researchers. Researchers face several challenges in trying to find this vaccine. Some of these challenges are discussed below.
Firstly, HIV attacks CD4+ T cells, which is the most essential part of immune system. This part directs and coordinates activities of the other types of immune cells which combat encroaching microbes. A vaccine can only be effective if it is able to activate these particular cells. This is mostly difficult since the cells are infected and then destroyed by HIV.
Additionally, scientists have been unable to identify the links of protection or immunity for HIV and are trying to design certain vaccines which will induce the proper immune responses that are necessary for protection. Different from other viral infections and diseases for which researchers have made successful vaccines, no documented cases of complete recovery from a HIV infection exists. As such, researchers of HIV vaccine do not have human ideal of recovery from infection or consequent protection from re-infection to aid them
In the body cells of an infected person, HIV mutates and recombines constantly to evolve into newer strains of virus which differ somewhat from the original infecting virus. This extensive HIV diversity poses a challenge to the design of vaccine. This is due to the fact that a vaccine for HIV would have to protect against numerous different virus strains that circulate all through the world. Ideally, a vaccine will marshal at least two types of immune response for fighting HIV. These are antibodies secreted by B cells and the T cells. Such immune responses would deter the spread or establishment of the virus from the original infection site and lessen the effects of the disease in those that become infected. Scientists have however not yet succeeded in stimulating both types of responses
Another hindering factor for researchers is that they lack knowledge about the HIV immunogens (pieces of HIV that can be used in constructing experimental HIV vaccine) that will get the human immune system to identify HIV during a real encounter and guard against it. To add on this, researchers lack practical animal model that can predict the efficiency of HIV vaccine in people, this hampers the development of cure for HIV. Presently, researchers tend to rely on experimenting using non-human primate models which are infected with simian HIV vaccine, referred to as SIV, and another engineered combination of HIV AND SIV, known as SHIV, to mimic the progression of the disease somewhat. To effectively evaluate experimental Vaccines in such animals requires either a SHIV or an SIV instead of the real vaccine candidate for HIV used for human being in clinical trials.