Stabilization of SARS-CoV-2 RNA in wastewater via rapid RNA extraction

Wastewater-based Epidemiology (WBE) has contributed to surveillance of SARS-CoV-2 in communities across the world. Both symptomatic and asymptomatic patients with COVID-19 can shed the virus through the gastrointestinal tract, enabling the quantification of the virus in stool and ultimately in wastewater (WW). Unfortunately, instability of SARS-CoV-2 RNA in wastewater limits the utility of WBE programs, particularly in remote/rural regions where reliable cold storage and/or rapid shipping may be unavailable. This study examined whether rapid SARS-CoV-2 RNA extraction on the day of sample collection could minimize degradation. Importantly, the extraction technology used in these experiments, termed exclusion-based sample preparation (ESP), is lightweight, portable, and electricityfree, making it suitable for implementation in remote settings. We demonstrated that immediate RNA extraction followed by ambient storage significantly increased the RNA half-life compared to raw wastewater samples stored at both 4 degrees C or ambient temperature. Given that RNA degradation negatively impacts both the sensitivity and precision of WBE measurements, efforts must be made to mitigate degradation in order to maximize the potential impact of WBE on public health.

Automated summary

Wastewater-based Epidemiology (WBE) has been effective in surveillance of SARS-CoV-2 worldwide. However, the instability of SARS-CoV-2 RNA in wastewater limits the utility of WBE programs, especially in remote areas. This study found that immediate RNA extraction and ambient storage can increase the RNA half-life, and a lightweight and portable extraction technology called exclusion-based sample preparation (ESP) can be used in remote settings.