HIV vaccine
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Marjan Khan M.B.B.S.[2]
Overview
HIV infection is a major global health issue, affecting 36.7 million people world-wide. The number of people living with HIV on antiretroviral therapy (ART) reached 17 million in 2015. Although ART has dramatically reduced morbidity and mortality in individuals with HIV infection and can also prevent HIV transmission but it cannot eradicate HIV infection due to the persistence of a latent viral reservoir, hence the need for ART is lifelong and the cost is substantial. Although ART is highly efficacious in preventing transmission in the setting of mother to child transmission, in sexual transmission through the treatment of infected partners in relationships, through pre-exposure or or post-exposure prophylaxis, but all these scale-up difficulties and costs may make widespread implementation challenging.Thus an HIV vaccine is essential as it is a more sustainable solution.The development of a universal effective HIV vaccine is an exceptionally difficult biomedical challenge. Firstly, no case of natural eradication of HIV infection has been identified, thus mechanisms of protection have not been definitively established. Secondly, the extreme diversity of HIV is a major obstacle as strains belonging to different subtypes can differ by up to 35% in their envelope (Env) proteins.Thus, vaccine immunogens derived from a particular strain may not be effective against other strain. To generate an efficacious global vaccine, immunogens capable of generating protective responses covering most major strains are required.
Historical Perspective
- Ever since HIV was formally identified as the cause of AIDS, there have been ongoing efforts on vaccines against the disease.
- On April 24, 1984, the US Secretary of Health and Human Services, Margaret Heckler, announced that vaccines will be researched and made ready for preliminary testing by the year 1986. [1]
- Traditional approaches of using live attenuated or whole inactivated viruses were considered unsafe because of the risk of permanently integrating proviral DNA within host chromosomes.[2]
- Advancements in vaccine development had to wait until mid-1980s when recombinant DNA technologies were becoming available for research applications. Following the success of recombinant Hepatitis B vaccine, recombinant DNA technologies were also being researched for HIV vaccines. [3]
- All these efforts came to a standstill with growing knowledge about extreme mutability and immune evasion mechanisms of existing HIV strains. [4]
- It was further complicated by the fact that neutralizing antibodies had no protective effects and their titers were similar among asymptomatic carriers and patients with active disease. [5]
HIV Vaccine
References
- ↑ "NEW U.S. REPORT NAMES VIRUS THAT MAY CAUSE AIDS - The New York Times".
- ↑ Dowdle W (1986). "The search for an AIDS vaccine". Public Health Rep. 101 (3): 232–3. PMC 1477690. PMID 3012619.
- ↑ Fischinger PJ, Robey WG, Koprowski H, Gallo RC, Bolognesi DP (September 1985). "Current status and strategies for vaccines against diseases induced by human T-cell lymphotropic retroviruses (HTLV-I, -II, -III)". Cancer Res. 45 (9 Suppl): 4694s–4699s. PMID 2410115.
- ↑ Wong-Staal F, Shaw GM, Hahn BH, Salahuddin SZ, Popovic M, Markham P, Redfield R, Gallo RC (August 1985). "Genomic diversity of human T-lymphotropic virus type III (HTLV-III)". Science. 229 (4715): 759–62. PMID 2992084.
- ↑ Cheng-Mayer C, Homsy J, Evans LA, Levy JA (April 1988). "Identification of human immunodeficiency virus subtypes with distinct patterns of sensitivity to serum neutralization". Proc. Natl. Acad. Sci. U.S.A. 85 (8): 2815–9. PMC 280090. PMID 3357892.