Ventilation strategies based on an aerodynamic analysis during a large-scale SARS-CoV-2 outbreak in an acute-care hospital

Nosocomial Coronavirus Disease 2019 during 2020–2021: Role of Architecture and Ventilation

“…The rate was, however, still high in patients who were infected in single or double rooms in the absence of identification of infected neighbors. For at least some of these cases without an unidentified infected source, a long-range contamination via virus-laden aerosols through corridors might be suspected, as reported by similar studies [19]. Although acquisition via HCWs or visitors cannot be ruled out, wearing a mask was mandatory for HCWs and visitors, and PPE was similarly recommended in M and H.…”

“…Low ACH due to NV in a department with a high rate of patients infected with COVID-19 (clusters), especially without regular ventilation in winter with low outdoor temperatures, may have contributed to these cases. Interestingly, in Park et al’s study, aerosol contamination was favored by the fact that in winter, the windows were closed and doors were opened, allowing for contamination through the corridor [ 19 ]. The source of nosocomial infections is frequently unknown among airborne viral agents, and a high incidence of asymptomatic, pauci-symptomatic, or pre-symptomatic infections [ 20 ] makes the implementation of transmission-based precautions nearly impossible [ 8 , 21 ], emphasizing the potential interest of universal precautions integrating the airborne risk [ 12 ].…”

“…The source of nosocomial infections is frequently unknown among airborne viral agents, and a high incidence of asymptomatic, pauci-symptomatic, or pre-symptomatic infections [ 20 ] makes the implementation of transmission-based precautions nearly impossible [ 8 , 21 ], emphasizing the potential interest of universal precautions integrating the airborne risk [ 12 ]. In addition to Park’s clinical study [ 19 ], the influence of MV and NV has already been emphasized in studies evaluating RNA detection, which is more common in healthcare settings with NV than in those with MV [ 13 , 22 ].…”

“…These corrective methods could include the integration of CO 2 captors monitoring CO 2 in medical departments, allowing alerts for levels >700 ppm, for example [ 23 ], and alerting HCWs to increase ACH by opening the windows. Modelization with the help of aerosol scientists of the natural airflow within a department is important to direct airflows “from clean to less clean” including when opening door and windows [ 12 , 19 ]. Moreover, adjusting exhaust fans to improve ACH can also be an easy way to ensure the best ACH.…”