Programs for HIV prevention have not made a lot of progress from the time that the virus was first discovered. Even if millions of dollars were invested into research and treatment, HIV prevention is still based upon protecting yourself or others from the HIV virus.
No HIV vaccination has been successful, and scientists are working on creating a vaccine since the HIV virus first emerged.
For a better understanding on why all the attempts of creating a vaccine for this virus have failed, to know what this virus does is extremely important. Unlike other viruses, the HIV virus has the ability to subscribe itself into the genetic code of the host. Other viruses simply brake into the cell and can easily be destroyed by the body cells, like in the flu virus, or can be eliminated by a proper treatment. Once the body has destroyed a virus, the white cells memory is "loaded" with the information of the virus. If the body is again exposed to such a virus, the white cells know exactly what to do to destroy it and produce the corresponding antibodies.
The cells memory can also be updated by a vaccine. This is practically formed by the dead ARN of the virus. Once placed into the body, the cells learn about it, and when they make contact, the cells know how to destroy the virus. The HIV infection becomes impossible only by the fact that the virus does not live just in the cell, or in the intercellular fluid. The ability to subscribe itself into the host's DNA makes it impossible to be destroyed without affecting the human cells. An HIV vaccination program must be based upon a genetic mutation of the human body to reject the HIV virus's gene. With today's technology, this is practically impossible.
However, in the first six months after contacting the HIV virus there is hope. A special treatment is applied to those that had direct blood or sexual contact with an HIV infected person. Most common cases occur in hospitals, where the medical personnel works with HIV infected people. For such people HIV prevention treatment is most important.
An HIV prevention measure has to be applied even if you are unsure of the fact that you have contacted the virus. The HIV virus can exist within the human body, in a latent state for over three years, so making it practically impossible for a proper diagnosis.
But HIV prevention should basically rely on protecting yourself by not having random unprotected sexual intercourse and avoiding blood contact as much as possible.