Figure 1.

Global risk factors for co-infection with hepatitis C virus and human T lymphotropic virus-1/2 in people who inject drugs. Adapted from Roger and Castro, 2014[15]. In this model, each circle represents a risk factor of hepatitis C virus (HCV)/human T lymphotropic virus-1/2 co-infection in people who inject drugs in the context of global migration patterns and increased health care-associated infections (HCAI; also known as “nosocomial” or “hospital-based” infections) in settings with limited resources, incarceration (particularly in countries that lack harm-reduction programs for incarcerated populations), and in the background of human immunodeficiency virus (HIV) or HCV infection.