HIV is one of the deadliest diseases that human race has been fighting for a long period of time. It has so far killed 23 million and an estimated 33 million are infected by the virus. HIV is a fast spreading virus that has gripped the world in its harsh claws. Several researchers are working hard on developing anti-HIV drugs. A recent study suggested that the battle between humans and the virus is getting tougher. According to an international study, HIV is fast evolving to fight the human immune system. The changing nature of the virus is only making the task of finding a vaccine to curb the virus from spreading harder.
The nature of the virus varies from person to person. The pace of the spread of the virus is not at the same rate in all. Without treatment, the virus in some people can take nearly ten years to progress into Aids, while in others; it might take merely 12 months. There are cases where the infection took around 20 years to develop into Aids. The reason behind this is the gene that controls the production of key immune system molecules called Human Leucocyte Antigens (HLA). The count of HLA differs in each individual and this difference makes the difference in the rate at which the virus spreads. 
Based on the analysis of the study, researchers showed that HIV has the ability to rapidly counter human genes that control the immune system molecules that can target it for destruction. This implies that the virus has the ability to neutralise the affect of the anti-HIV drug. However, experts say that in spite of the huge challenge the virus has thrown on human kind, there is no reason for despair. The need of the hour, according to many is to constantly update the vaccine in order to curb the high speed evolution of the virus. More information can be found from the source article.