Low Resource Assay for Tracking SARS-CoV-2 in Wastewater

Wastewater based epidemiology (WBE) allows for the tracking of nucleic acid of SARS-CoV-2 in wastewater which gives the opportunity for the public and government officials to be informed about the infectivity of the virus in a community. Advances have been made in WBE that have allowed for higher performance, lower resource use, and faster turnaround time. An adapted concentration method of spin column direct extraction has yielded a proxy virus recovery of 83%, consumable cost of $2.01 per sample, and a turnaround time of 0.33 hour/sample. Other concentration methods have lower proxy virus recoveries, comparable cost, and comparable turnaround time. The concentration methods that are reviewed are direct extraction, HA filtration, ultrafiltration, ultracentrifugation, magnetic bead absorption, and precipitation. The advantage to the spin column direct extraction method is it serves as a concentration and extraction method which saves time and resources. There are a series of common steps in sample processing that goes as follows: pretreatment, heat pasteurization, concentration, extraction, and analysis. Each step contributes to the loss and/or recovery of the nucleic acid. It is important to evaluate each step of the process to have a comprehensive review of the protocol. Factors used for the evaluation are performance, resource use, and turnaround time. This study compared the newly adapted spin column direct extraction to HA filtration + bead beating. In addition, this method was compared to other reported methods and their values of spike recovery, cost, and throughput time. Under these parameters, the spin column direct extraction proved to have high performance, low resource use, and fast turnaround time