Bidirectional Synergistic Interaction Between Influenza Virus and SARS-CoV-2 in the Postpandemic Era: A Modeling Study

Introduction

Influenza and COVID-19 are major respiratory diseases whose co-circulation dynamics are not fully understood. Surveillance data from the postpandemic period, free from the confounding effects of nonpharmaceutical interventions (NPIs), provide a unique opportunity to study their interactions. This study aimed to (1) estimate the direction and strength of the epidemiological interactions between influenza virus and SARS-CoV-2 and (2) quantify the impact of these interactions on the cumulative disease burden.