This symposium intends to provide a discussion platform for all scientists interested in the biology of virus infection and antiviral immunity as well as countermeasure development, which is urgently needed for a range of viral pathogens. The meeting will promote the exchange of novel and conceptual ideas in this fast-evolving field and will foster interdisciplinary collaborations that are essential to sustain the rapid progress our field has seen over the past several years. We intend to engage a diverse group of scientists from academia, industry, and government to discuss a broad range of topics related to viral immunology, pathogenesis, evolution, prevention, and treatment. The meeting will comprise the following six sessions: 1) Host-virus interactions in innate immunity; 2) Species expansion of (re)emerging viruses and associated immunity; 3) Success and failures of adaptive immunity to acute and persistent virus infections; 4) Genetic and acquired immune factors modulating viral susceptibility; 5) Novel approaches of host-directed and immune-based therapies to virus infections; and 6) New approaches and technologies to optimizing vaccine-induced immunity to viral pathogens. To attract a broad audience, we will have a balanced representation of cutting-edge fundamental research discoveries. A focus here will be on host-directed, immune-based therapies and vaccines, which are increasingly appreciated by the field. Providing virologists and immunologists with this opportunity to discuss their recent research findings including major successes and challenges in therapeutics/vaccines development is expected to facilitate interdisciplinary collaborations and, ultimately, promote scientific advancement for combating (re)emerging and persistent viral infections.