 30 years of research on HIV has not resulted in a vaccine to prevent infection or limit disease progression, but a heterologous prime boost regimen using DNA as the priming agent and attenuated vaccinia virus-modified vaccinia anchora, MVA, as a boosting vector has shown promising results in non-human primate models and SIV infection models. Immunological correlates of protection have been determined and potential approaches for improving protective immunity are being explored. The field will likely focus on understanding vaccine-induced immune responses and immune correlates of protection in the next five years. This article was offered by Lynette Sivccia and Rama Ayo Amara.