As one would expect of a newly characterized disease, much knowledge about the microbiology, pathogenesis, natural history, and epidemiology of SARS remains to be discovered. For example, scientists have not yet identified the animal source of the infectious agent and have not determined whether a persistent animal reservoir of the infectious agent exists. It is also unclear whether SARS, like influenza, is a seasonal disease that would have receded on its own. Along the same lines, it remains to be seen whether SARS will reemerge on a seasonal basis, and if so, how virulent future manifestations of SCoV will be. These and other unanswered scientific questions, listed in , were a prominent theme of workshop presentations and discussions. Answers to these questions would certainly advance the world’s ability to predict and prepare for a resurgence of SARS.