Assessing the interactions between COVID-19 and influenza in the United States

Casey M Zipfel; Shweta Bansal

To understand the process of respiratory disease transmission and mitigation, we developed a metapopulation model that represents age-specific contact between children and adults within metropolitan areas and is spatially divided into metropolitan areas linked through air tra c flows. The model is described in detail in [7] . We simulated a seasonal influenza epidemic in the US, including typical holiday school closure, and seasonality with the season ending at April 30, 2020. We then incorporated reduction in age-structured transmission by (1 ⌧ (t)), where is the intensity of transmission decrease, which relates to the increase in risk perception level of ⌧ (t). We parameterize ⌧ (t) based on daily Google trends for COVID-19 and fit to assess the degree to which influenza transmission is reduced in the early stages of COVID-19 in the US. We consider two main possible mechanisms by which COVID-19 may have resulted in decreased transmission: 1) increased risk perception of respiratory transmitted disease resulting in precautionary behaviors, like increased handwashing, that reduce potentially transmissible contacts and 2) isolation of infected individuals, either due to undetected COVID-19 spread, or increased messaging surrounding remaining home if one is feeling ill for any reason.