Evaluation of a novel direct capture method for virus concentration n wastewater from COVID-19 infectious ward and correlation analysis with the number of inpatients.

The global outbreak of the SARS-CoV-2 pandemic has increased the focus of Wastewater-based epidemiology (WBE) studies as a tool for understanding the epidemic and risk management. A highly sensitive and rapid method for the virus concentration from wastewater is needed to obtain the accurate information for early detection of SARS-CoV-2 outbreak and epidemic. In this study, we evaluated the efficiency of the direct capture method provided from Promega, based on column adsorption using the wastewater from actual infectious diseases ward. The efficiency of the nucleic acid extraction-purification process was also evaluated by Maxwell(R) RSC instrument (fully automated extraction) and QIAamp Viral RNA mini kit (manual extraction). The obtained SARS-CoV-2 data from wastewater were analyzed with the number of inpatients which is the consideration of the severity and the days of onset. The combination of direct capture and Maxwells method (DC-MW) was suggested to be a highly sensitive and simple method with better concentration efficiency and quantification than other methods. Moreover, the inpatient conditions (severity and days of after onset) should be considered to accurately understand the actual status of the correlation between the number of inpatients and SARS-CoV-2 concentration in wastewater. The highly sensitive method of DC-MW was suggested to assess more actual situation of SARS-CoV-2 shedding into the wastewater.