Although new treatment and prevention technologies have had a positive impact on the HIV epidemic, unmet subsistence needs, social marginalization, criminalization and other structural factors have yet to be resolved. Social factors leave key populations at significantly higher risk of HIV infection, limit access to treatment, care and support services and lead to poorer health outcomes. Because of these social drivers, HIV is increasingly concentrated among people and populations marginalized by poverty, homelessness, inequity, stigma and substance use. These pages capture the results of OHTN research into the social drivers of HIV.