Considering the isolation of infected patients and the proportion of critically ill individuals requiring single-room management is crucial when implementing public health measures during nosocomial outbreaks such as coronavirus disease-2019. Using a mathematical model, we aimed to assess the level of hospital occupancy restriction required for the adequate isolation of infected and exposed patients while providing for critically ill patients requiring single-room management.

Patients were categorized into four groups: susceptible, exposed, infected, and recovered. We modeled a hospital ward with mixed room types, incorporating critically ill patients and sporadic unidentified infections, to evaluate isolation feasibility through simulations.

Simulation results showed that patient isolation became difficult under high-occupancy conditions. The feasibility was also affected by infection control strategies, such as discharging infected or exposed patients and isolating exposed individuals in single rooms.

Higher occupancy increases the risk of failed isolation measures, potentially promoting in-hospital transmission. However, this model does not incorporate long-distance airborne transmission or the effects of ventilation, and coronavirus disease-2019 can spread via aerosols.

This model could be a valuable reference for determining appropriate hospital occupancy rates to ensure effective infection control during nosocomial outbreaks.