Hopes of a total cure for HIV have been dealt a blow, after researchers in the US discovered that the "reservoir" of inactive viruses in a patient's body may be up to 60 times larger than previously thought.
Although modern drug treatments have proved hugely effective at controlling the HIV virus, enabling patients to live long and full lives and reducing infection rates, they do not kill all the viruses in an infected individual.
These viruses remain a threat because they can become active again if a patient stops taking their antiretroviral drugs. The findings, published in the journal Cell following a study at the Howard Hughes Medical Institute (HHMI) in Maryland, were "discouraging" experts said, but should re-focus efforts to make sure HIV positive people are getting the treatment they need.
"The findings suggest that there are a lot more of these proviruses that we have to worry about than we thought," said Robert Siliciano, an HHMI investigator at The Johns Hopkins University, who led the new study. "It doesn't mean that it's hopeless, but it does mean we need to focus on getting an even clearer idea of the scope of the problem."
In HIV positive patients the virus targets the immune system's T cells, and becomes integrated into the cell's genes, making the cell reproduce the virus. Antiretroviral drugs target these active forms of the virus, but in some cells, the virus remains inactive. It is this type of virus that researchers now believe is far more numerous than previously thought. As of yet, researchers have no way of eradicating inactive HIV viruses.