Speaker: Samantha Brozak (Arizona State University)

Location and Time: AC1 115, 10:10–10:40am

Title: A wastewater-based harmless delay differential equation model for SARS-CoV-2 variant competition

Abstract: We model the dynamics of a two-strain disease spreading through a population, where the emergent strain has the ability to infect individuals who were previously infected by the established strain. Temporary cross immunity is included in the form of a time delay (later shown to be harmless). We provide conditions for the local and global stability of the disease-free equilibrium and the two boundary equilibria where one strain outcompetes the other. Due to the immune evasion of the emergent strain, the reproduction number of the emerging strain must be sufficiently lower than the reproduction number of the established strain for the persistence of the established strain and extinction of the emergent strain. The unique coexistence equilibrium is analyzed using a quasi-steady-state argument. The model is validated using wastewater surveillance data from the Deer Island Treatment plant during the SARS-CoV-2 Alpha and Delta Waves from October 2020 to May 2021.