¶ … progress of vaccine development, particularly the challenges. There is also a discussion of funding and its impact on HIV research.
Ever since HIV / AIDS made the evolutionary jump from chimpanzees to humans, it has infected approximately one percent of the global population; in 2005 it killed almost three million people alone. HIV's continued spread is due to its ability to evade the human immune system and vaccines (Understanding Evolution, 2007).
Even with recent advances in scientists' understanding of HIV origination, development and immunology, there are still major scientific obstacles. Several prototype HIV vaccine candidates have failed so far to protect against HIV infection or to reduce viral loads, that is, the concentration of HIV virus in the blood after infection during clinical studies of effectiveness. Therefore there must be a renewed, well-coordinated commitment to conducting basic discovery research as well as preclinical studies and clinical trials (Barouch, 2008).
In the nearly 30 years since HIV was identified as the agent that causes AIDS, more than 60 million people worldwide have been infected with HIV. Most of these individuals live in the developing world and nearly half of them have died. The ideal solution would be the development of a safe and effective HIV vaccine to control the worldwide AIDS pandemic, but HIV vaccine development efforts have been largely unsuccessful so far. According to Dan Barouch (2008) of the Harvard Medical School, this lack of success is due to the "extraordinary diversity of HIV-1, the capacity of the virus to evade adaptive immune responses, the inability to induce broadly reactive antibody responses, the early establishment of latent viral reservoirs, and the lack of clear immune correlates of protection…"
The goal of developing an HIV vaccine is to either prevent infection, or to reduce the concentration of HIV virus in the blood after infection, or to lessen clinical disease progression after infection. The ideal vaccine would completely block infection as well as provide sterilizing immunity. However, most clinically licensed vaccines do not do all these things. A more realistic goal would...
Such partial control, shown by a reduction in peak and setpoint viral loads following infection, has been demonstrated in certain preclinical studies by vaccines that cause T. lymphocyte responses. Given that viral loads are the primary factor in HIV transmission, it is possible that a partially protective vaccine could have a significant impact on a population level (Barouch, 2008). In spite of the urgency, only two vaccine concepts had completed clinical efficacy studies as of 2008. Results of those studies highlighted new scientific challenges and led to significant debate regarding the optimal path forward for the field of HIV vaccine.
HIV vaccine strategies can be divided into two categories, traditional and novel approaches. Traditional vaccine technologies include the use of live attenuated viruses, whole killed viruses and protein subunits. Live attenuated viruses are not likely to be used in humans because of significant safety concerns, while whole killed have shown limited ability to produce reactive responses. Novel vaccine strategies include gene delivery technologies such as plasmid vaccines and live recombinant vectors. Both types of novel strategies are undergoing further evaluation (Barouch, 2008).
Developing a successful HIV vaccine requires that this field be able to attract and keep talented new investigators. Increased support for fellows and junior faculty should be considered a top priority for both senior investigators and funding organizations. Continued participation by industry is also necessary, since biotechnology and pharmaceutical companies have important capabilities that academic, government and non-profit organizations do not (Barouch, 2008).
More recent developments in 2010 included the demonstration of modest protection against HIV infection in humans through immunization, using a vaccine regimen including canary-pox-vector prime plus a protein-subunit boost in the RV144 trial in Thailand. Such news is encouraging given that for every two patients who begin receiving HIV…
