When to start treatment for HIV is still a complex question. In the UK, current guidelines say antiretroviral therapy (ART) should be started if and when the CD4 count (a measure of how well the immune system is performing) drops from its normal range of between 500 and 1500 copies to below 350 copies (though there are a few other circumstances where ART might be initiated sooner). In the US and some other European countries, however, ART is started when the CD4 count drops below 500 copies. The evidence of whether or not there are clinical benefits for the individual in starting ART earlier are not clear, and a large study called START should provide this much-needed information in early 2016.
The initial thinking about delaying ART was based on concerns about adverse side-effects of the early HIV drugs; however, modern HIV drugs are well-tolerated and easy to take, so to a large extent, this concern has been allayed. There is a belief that when untreated, even with high CD4 counts, HIV continues to damage the immune system, and so treatment should be started as soon as possible; however, the data for this is not clear yet – hence the need for the START study.
There may be another reason for starting ART sooner. There is now clear evidence that for someone who is successfully taking ART, and who has had a non-detectable viral load (a measure of how much HIV is in the blood) for 6 months, then the risk of onward transmission of HIV is significantly reduced to almost zero, offering protection that is as good as condom use. This has led to the idea of Treatment as Prevention (TasP). In the UK, many more people are asking to start ART sooner, to reduce the risk of transmission. This is something that is supported in the current UK HIV treatment guidelines, and is something that clinicians should discuss with all new HIV patients when thinking about ART.
The full article can be read here.
More information on the SMART study can be found here.
More information on TasP can be found here.