SARS-CoV-2 Airborne Surveillance Using Non-Powered Cold Traps

Abstract

Background: COVID-19 pandemic is a worldwide challenge requiring efficient containment strategies. High-throughput SARS-CoV-2 testing and legal restrictions are not effective in order to get the current outbreak under control. Emerging SARS-CoV-2 variants with a higher transmissibility require efficient strategies for early detection and surveillance. Methods: SARS-CoV-2 RNA levels were determined by quantitative RT-PCR in aerosols collected by non-powered cold traps. SARS-CoV-2 spreading kinetics and indoor hotspots could be identified in isolation units and at public places within a high-endemic area. These included an outpatient endoscopy facility, a concert hall, and a shopping mall. Results: Indoor COVID-19 hotspots were found in non-ventilated areas and in zones that are predisposed to a buoyancy (chimney) effect. SARS-CoV-2 RNA in those aerosols reached concentrations of 10^5 copies/mL. Extensive outdoor air ventilation reliably eliminated SARS-CoV-2 aerosol contamination. Conclusions: The method presented herein could predict SARS-CoV-2 indoor hotspots and may help to characterize SARS-CoV-2 spreading kinetics. Moreover, it can be used for the surveillance of emerging SARS-CoV-2 variants. Due to low costs and easy handling, the procedure might enable efficient algorithms for COVID-19 prevention and screening.