Nichols BE, Boucher CAB, van de Vijver DAMC (Erasmus Medical Centre, Erasmus University, Rotterdam, the Netherlands). HIV testing and antiretroviral treatment strategies for prevention of HIV infection: impact on antiretroviral drug resistance (Symposium). J Intern Med 2011; 270: 532-549. 'Test and treat' is a strategy in which widespread screening for human immunodeficiency virus (HIV) is followed by immediate antiretroviral therapy for those testing positive, thereby potentially reducing infectiousness in larger cohorts of infected patients. However, there is a concern that test and treat could lead to increased the levels of transmissible drug-resistant HIV, especially if viral load and/or drug resistance is not routinely monitored. Reviews of the existing literature show that up to now, even in the absence of laboratory tests, drug resistance has not created major problems in sub-Saharan Africa. Here, we discuss the current evidence for the effectiveness of a preventive test and treat approach and the challenges and implications for daily clinical practice and public health.