Mitigating Airborne Infection Transmission in the Common Area of Inpatient Wards—A Case Study

In a hospital ward, transmission of airborne pathogens can occur in any area where people breathe the same air. These areas include patient rooms and specialised treatment rooms, as well as corridors and common areas. Numerous studies have been conducted to investigate the risk of airborne transmission within hospital rooms where patient care activities take place; however, studies assessing the risk of exposure to airborne pathogens in common areas such as nurse stations and corridors, in which healthcare workers spend up to 63% of their time, are very rare. In this study, we addressed this gap by simulating aerosol transport in the common area of a real inpatient ward encompassing different types of patient rooms and equipped with a mixing ventilation system. The risk of airborne transmission of COVID-19 in the ward was evaluated using a spatially resolved risk model, coupled with the clinical and pathological data on SARS-CoV-2 infection. The results showed that the central-return ventilation system causes directional air flows in the corridors, which enhanced long-distance aerosol transport and were conducive to infection transmission between different rooms. An improved ventilation system was proposed that aimed to reduce air mixing and minimise directional air flows. The improvement involved only rearrangement of air supply and exhaust vents, but led to significant reductions in both particle residence time and travelling distance within the ward, contributing to a nearly two-fold increase and 60% decrease in the areas of low-risk and high-risk zones, respectively, resulting in a 34% reduction in the overall infection probability in the studied area. This study demonstrated the potential of preventing hospital-acquired infection (HAI) via engineering controls and provided recommendations for future studies to assess novel ventilation configurations to reduce transmission risk.