The aerobiology of SARS-CoV-2 in UK hospitals and the impact of aerosol generating procedures

Abstract

Background: SARS-CoV-2 nosocomial transmission to patients and healthcare workers (HCWs) has occurred throughout the COVID-19 pandemic. Aerosol generating procedures (AGPs) seemed particularly risky, and policies have restricted their use in all settings. We examined the prevalence of aerosolized SARS-CoV-2 in the rooms of COVID-19 patients requiring AGP or supplemental oxygen compared to those on room air. Methods: Samples were collected prospectively near to adults hospitalised with COVID-19 at two tertiary care hospitals in the UK from November 2020-October 2021. The Sartorius MD8 AirPort air sampler was used to collect air samples at a minimum distance of 1.5 meters from patients. RT-qPCR was used following overnight incubation of membranes in culture media and extraction. Results: We collected 219 samples from patients' rooms: individuals on room air (n=67), receiving oxygen (n=65) or AGP (n=67). Of these, 54 (24.6%) samples were positive for SARS-CoV-2 viral RNA. The highest prevalence was identified in the air around patients receiving oxygen (32.3%, n=21, CI95% 22.2 to 44.3%) with AGP and room air recording prevalence of (20.7%, n=18, CI95% 14.1-33.7%) and (22.3%, n=15, CI95% 13.5-30.4%) respectively. We did not detect a significant difference in the observed frequency of viral RNA between interventions. Interpretation: SARS-CoV-2 viral RNA was detected in the air of hospital rooms of COVID-19 patients, and AGPs did not appear to impact the likelihood of viral RNA. Enhanced respiratory protection and appropriate infection prevention and control measures are required to be fully and carefully implemented for all COVID-19 patients to reduce risk of aerosol transmission.

An optimised method for the recovery of laboratory generated SARS-CoV-2 aerosols by plaque assay

“…A small number of studies have detected viral RNA from the air of hospital rooms [5][6][7][8], with only one group able to demonstrate recovery of viable virus [9,10]; however, to date, recovery and quantification of aerosolised SARS-CoV-2 has yet to be demonstrated. Here, we utilise a portable air sampler that is battery powered and has proven effective at capturing SARS-CoV-2 RNA from hospital rooms [11]. Whilst viral recovery optimisation has been demonstrated by the manufacturer (Sartorius, Germany) the method relies on mechanical agitation of the membrane and the additional of chemicals.…”