Dynamics of epidemic models incorporating a hospitalization compartment with a nonlinear recovery rate

We propose new mathematical models based on ordinary differential equations to investigate the transmission dynamics of infectious diseases by adding a hospitalization compartment [Formula: see text] into the classic [Formula: see text] and [Formula: see text] models. The models incorporate a general incidence rate between susceptibles and infected individuals and a nonlinear recovery rate for hospitalized individuals. We rigorously analyze the existence, local stabilities, and global stabilities of equilibria and derive threshold conditions determining whether the disease dies out or persists. As an application of our [Formula: see text] model, we perform a case study with an endemic of COVID-19, conduct data fitting and sensitivity analysis for model parameters, and present simulation results to emphasize the role of the hospitalization rate.