As we see millions of deaths taking place, as a result of HIV infection, the need for an HIV vaccine is getting stronger and stronger, making it an absolutely indispensable necessity in recent times. Due to this very reason, many tests have been conducted, all across the globe. Although these results have failed to show any positive results so far, yet research work is under progress. As a matter of fact, it becomes all the more necessary to develop a vaccine with large number of undetected cases, moving around.
It is to be noted that a few vaccines have been developed in the past. However, these vaccines have been rendered useless due to the fact that HIV is a highly mutable virus. It is also the ability of the virus to thwart the pressure extended by humoral as cellular immunity system, which is making it difficult to develop a vaccine. Along with this, HIV isolates are also highly variable, which is degrading the situation further. Thus, any vaccine needs to be broad enough to deal with the highly variable characteristic of the disease, to be effective enough.
Currently, there are around 80 vaccine candidates undergoing tests in phase one trials, expectedly five in phase one/two trials and one in phase three trial. In most of these trials, focus lied on the HIV envelope protein; which resulted in the evaluation of at least ten different candidates belonging to the gp120 and gp160 categories, in tests, which were conducted by the AIDS Vaccine Evaluation Group.
An important development in this regard was the STEP study which kick started in 2004. As many as 3000 candidates were selected and the study was conducted by the HIV Vaccine Trials Network in association with Institute of Allergy and Infectious Diseases along with Merck & Co. which is a Pharmaceutical company. Merck & co. is known for the development of the experimental vaccine V520 which was supposed to stimulate cellular immunity, by advancing the growth of T cells that kill HIV infected cells.
However, V520 was soon found out to be ineffective, as it contained only three HIV genes. Apart from that, it also appeared that conditioned worsened in case of HIV1 infections. This lead to the discontinuation of trials, related to V520 in 2007. Latest development in this regard has been the development of Modified Vaccina Ankara. Trials suggested that it provided partial protection in some models.
Laboratories all across the globe are trying to find a vaccine for HIV. If at all a vaccine is developed, then it would be a great step in the direction of eradication of HIV/AIDS.