Richard Skolnik covers HIV as part of Yale's Essentials of Global Health course, focusing on the disease's global burden and the populations most affected by it. He walks through how HIV spreads, the epidemiology of infection rates across regions, and the risk factors that drive transmission, from behavioral patterns to structural inequities in access to care. The lecture reviews what public health interventions have proven cost-effective, including prevention campaigns, testing programs, and antiretroviral treatment rollouts, drawing on data from hard-hit countries. Skolnik situates HIV alongside other communicable diseases covered in the course, such as TB and malaria, to show common patterns in how global health responses get designed and funded. The session stays practical, oriented toward what has actually worked in reducing infection and death rates rather than abstract theory.