is HIV vaccine possible?
Read to know details about HIV vaccine.
What is HIV?
Human immunodeficiency virus (HIV) is a lentivirus (a member of the retrovirus family) that causes acquired immunodeficiency syndrome (AIDS),a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive.
Difficulties in developing vaccine
There are a number of factors that cause development of an HIV vaccine to differ from the development of other classic vaccines
Classic vaccines mimic natural immunity against reinfection generally seen in individuals recovered from infection; there are almost no recovered AIDS patients.
Most vaccines protect against disease, not against infection; HIV infection may remain latent for long periods before causing AIDS.
Most effective vaccines are whole-killed or live-attenuated organisms; killed HIV-1 does not retain antigenicity and the use of a live retrovirus vaccine raises safety issues.
Most vaccines protect against infections that are infrequently encountered; HIV may be encountered daily by individuals at high risk.
Most vaccines protect against infections through mucosal surfaces of the respiratory or gastrointestinal tract; the great majority of HIV infection is through the genital tract.
The ineffectiveness of previously developed vaccines primarily stems from two related factors.
First, HIV is highly mutable. Because of the virus' ability to rapidly respond to selective pressures imposed by the immune system, the population of virus in an infected individual typically evolves so that it can evade the two major arms of the adaptive immune system; humoral (antibody-mediated) and cellular (mediated by T cells) immunity.
Second, HIV isolates are themselves highly variable. HIV can be categorized into multiple clades and subtypes with a high degree of genetic divergence. Therefore, the immune responses raised by any vaccine need to be broad enough to account for this variability. Any vaccine that lacks this breadth is unlikely to be effective.
Possible hopes from the future for the development of vaccine..
Emerging technologies that enable the identification of T-cell-receptor specificities and cytokine profiles will prove valuable in hastening this process. In July 2012 a science group speculated that that an effective vaccine for HIV would be completed in 2019.
A vaccine, SAV001, that has had success in animal subjects began Phase 1 human trials in London, Ontario in 2011.