Simplifying SARS-CoV-2 wastewater-based surveillance using an automated FDA EUA assay

TL;DR

Researchers tested an automated FDA-approved SARS-CoV-2 test for wastewater surveillance and found it works well with less labor than traditional methods.

Contribution

The study demonstrates the feasibility of using an FDA EUA assay for wastewater-based SARS-CoV-2 surveillance with an automated platform.

Findings

The FDA EUA assay detected SARS-CoV-2 in wastewater with results comparable to standard lab methods.

The automated assay required less labor and faster processing than traditional methods.

Viral RNA levels decreased by 33.9% after three freeze-thaw cycles.

Abstract

Wastewater-based surveillance (WBS) can track the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in communities. Laboratory methods for this testing involve labor-intensive, multi-step processes. This study assessed the feasibility of performing WBS with an off-label use of an automated commercial SARS-CoV-2 assay that had received Emergency Use Authorization for human diagnostic testing from the United States Food and Drug Administration (FDA EUA). Twenty-four-hour composite samples of primary influent wastewater from seven municipalities in New Hampshire and Vermont were collected between September 2020 and February 2021, and were centrifuged upon receipt. An aliquot of fresh supernatant was immediately tested with the Abbott m2000 RealTime SARS-CoV-2 assay (Abbott Molecular, Des Plaines, IL, USA). Corresponding aliquots were then stored at −80°C until they were thawed, polyethylene glycol (PEG) concentrated, and tested by two PCR-based laboratory-developed tests (LDTs). Wastewater samples (103) were tested with successful detection of SARS-CoV-2 viral RNA by all three methods. Bland-Altman analysis showed overall concordant results with a bias of −0.13 and −0.42 log copies/mL detected by the FDA EUA assay compared to the LDTs. Specimen stability assessment demonstrated a decrease of 33.9% measurable viral RNA after three freeze-thaw cycles. SARS-CoV-2 detection in wastewater using an FDA EUA assay on an automated commercial testing platform performed comparably but with more efficient workflow when compared to two LDTs. This sample-to-answer automated method could save time and labor for surveillance testing, but further validation of its ability to quantitate SARS-CoV-2 viral RNA is necessary.

This proof-of-principle study evaluates an off-label use of an automated United States Food and Drug Administration (FDA) Emergency Use Authorization (EUA) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) human diagnostic assay for wastewater surveillance. Compared to standard, labor-intensive, multi-step methods currently in use for wastewater surveillance testing, an off-label use of an FDA EUA assay on an automated platform offers a sample-to-answer testing requiring less labor and a faster turnaround time.

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