An elite controller is a person living with HIV who is able to maintain undetectable viral loads for at least 12 months despite not having started antiretroviral therapy (ART) . Elite controllers are rare: for every two hundred people living with HIV, approximately one may be an elite controller (0.5%).
It is not entirely understood why some patients are able to achieve undetectable viral loads without ART. There is good evidence to suggest that a person’s individual immune response plays the most crucial part in maintaining viral suppression. This can be due to genetic influences and/or the way the immune system reacts and adapts to the early stage of HIV infection.
There is variety amongst elite controllers in the extent to which viral replication is suppressed. In some there may be little to no ongoing replication anywhere in the body. Others demonstrate evidence in the blood of ongoing viral replication somewhere in the body, but not enough to cause a detectable viral load.
The term doesn’t describe a permanent state; elite controllers frequently go on to develop detectable virus in the blood, as well as other HIV-related complications. In one study, the median time to disease progression for elite controllers was four years. In other words, if there were 100 elite controllers, by four years, 50 of them would either have a detectable viral load, falling CD4+ count or an AIDS-defining illness.
People classed as elite controllers are at higher risk of cardiovascular events and AIDS-defining illnesses than those with well controlled HIV who are taking ART. International guidelines vary, but there is a school of thought that given the tolerable side effect profile of modern ART, elite controllers gain health advantages by starting treatment.
With guidelines now recommending starting treatment at diagnosis it is possible that the pool of elite controllers may decline, as it will be impossible to tell which people would have otherwise controlled HIV without treatment.
There are related sub-groups of people living with HIV. ‘Viraemic controllers’ are able to maintain a low viral load off ART with CD4 counts above 200. ‘Post-treatment controllers’ are able to maintain undetectable viral loads despite stopping ART. These groups of people provide compelling examples of how the immune system can inhibit viral reproduction without antiretrovirals.
A similar term, but not interchangeable, is ‘long term non-progressors’ – people who are able to maintain CD4 counts greater than 500 without ART, for a prolonged period of time (at least eight years in most studies). There are some elite or viraemic controllers who may also be classed as long-term non progressors and vice versa.
Much is still to be learned about the exact conditions required to gain control of the virus without ART, but the understanding gained so far is already being applied to further both vaccination and cure research. With the appropriate resources, willpower and perhaps good fortune, elite controllers and others like them may hold the key to unlocking a whole new era of HIV prevention and management.