A Joint Compartmental Model for The Co-infection of SARS-CoV-2 and Influenza

Co-infection of COVID-19 and other respiratory pathogens, including influenza virus family, has been of importance since the beginning of the recent pandemic. As the upcoming flu season arrives in countries with ongoing COVID-19 epidemic, the need for preventive policy actions becomes more critical. We present a joint compartmental SEIRS-SIRS model for the co-circulation of SARS-CoV-2 and influenza and discuss the characteristics of the model, such as the basic reproduction number (R0) and cases of death and recovery. We implemented the model using 2020 to early 2021 data derived from global healthcare organizations and studied the impact of interventions and policy actions such as vaccination, quarantine, and public education. The VENSIM simulation of the model resulted in R0 = 7.5, which is higher than what was reported for the COVID-19 pandemic. Vaccination against COVID-19 dramatically slowed its spread and the co-infection of both diseases significantly, while other types of interventions had a limited impact on the co-dynamics of the diseases given our assumptions. These findings can help provide guidance as to which preventive policies would be most effective at the time of concurrent epidemics, and contributes to the literature as a novel model to simulate and analyze the co-circulation of respiratory pathogens in a compartmental setting that can further be used to study the co-infection of COVID-19 or similar respiratory infections with other diseases.