The SPARS Scenario features an outbreak of the novel SPARS coronavirus first identified in a major US city in 2025. Over a 3-year period, the virus spreads to every US state and more than 40 countries, where case fatality rates vary depending on the capabilities of local health systems. In the United States, an existing drug is repurposed to treat SPARS symptoms while federal regulators work with a pharmaceutical company to fast-track the production of a SPARS vaccine. The response differs in other nations. What follows is a nationwide vaccination effort and lingering strains on the US healthcare sector from a steady stream of patients seeking treatment for serious post-SPARS complications.