Resistance: Introduction

Current treatment regimens for HIV infection generally employ combinations of three or more potent antiretroviral drugs, which in many cases can drive down the level of virus in the body to undetectable levels. However, this approach is not always successful. A significant number of individuals have persistently high levels of HIV despite potent medication, while others experience only transient virological suppression before their viral load rapidly rebounds to near pre-treatment levels.

One of the major causes of treatment failure is HIV drug resistance – the "Achilles’ heel" of antiretroviral therapy. This section explains what causes HIV resistance, how it can be monitored, and what steps can be taken to minimise its potential impact on successful treatment.