History of HIV Controllers
More than a decade into the recognition of the HIV epidemic, it became clear that there was a group of HIV infected persons whose HIV disease did not progress over an extended period of time. Such individuals, then called HIV long-term non-progressors, were defined by their lack of HIV-related symptoms and high CD4 T cell counts that remained stable for periods of 7 years or longer. Unfortunately, many of these early described individuals’ eventually experienced CD4 T cell decline and disease progression.
But as time has progressed and as it has become possible to measure the amount of HIV in the blood stream, it has become clear that a small fraction of these people are able to maintain long term control of virus to undetectable or nearly undetectable levels. Such HIV controllers are a subset of HIV infected individuals who are able to keep the virus from replicating without the aid of treatment. About 1 out of every 300 infected persons is an HIV controller.
Viral Load and HIV Progression
The majority of people infected with HIV are not able to control viral replication on their own so the virus replicates unchecked and reaches high levels in the circulating blood. These levels can be checked by a viral load assay, which is reported in HIV viral copies per milliliter of blood. Studies have shown that the amount of virus circulating in an individual’s blood is associated with the rate of disease progression. Specifically, people with higher viral loads progress to AIDS more quickly than those with lower viral loads.
Studies have also shown that people with higher viral loads are more likely to transmit HIV to others. Lower levels of virus are thus beneficial to the individual, because they predict longer AIDS-free survival, and to overall public health, because they may reduce the rate of transmission. Some HIV controllers are able to maintain levels of virus that are so low that they are termed “undetectable,” these individuals have been described in the literature as elite controllers or elite suppressors.