While it is recognized that frequent, repeat testing for SARS-CoV-2 could help control the covid-19 pandemic in local communities, such aggressive testing has been rarely put into practice due to costs, logistics, and supply chain limitations. Specifically, swabs, viral transport medium, and RNA isolation kits used in standard testing have all been in short supply at various times during the pandemic. This lecture will describe the development of a saliva-based RT-qPCR test for SARS-CoV-2 that bypasses the need for RNA isolation/purification. Specifically, we discovered and deployed a streamlined process whereby tubes containing saliva are heated at 95<sup>o</sup>C for 30 minutes, followed by addition of a buffer, and then analyzed by RT-qPCR. This simple process results in a highly sensitive test (Limit of Detection of ~1000 viral particles/mL) and one that is safe on scale (any virus in saliva is inactivated before opening the tubes). The University of Illinois, Urbana-Champaign (UIUC) routinely used this process on &gt;10,000 samples per day during the 2020-2021 academic year, running over 1,000,000 tests during the fall semester. The sensitivity, specificity, and accuracy of this method will be discussed, as will results comparing this method head-to-head with antigen-based methods in daily testing of asymptomatic individuals, showing that this saliva/RT-qPCR test identifies positives days before antigen testing. The ability of this testing to identify individuals in the early stage of transmission, while their viral load is still increasing and while they are asymptomatic, has mitigated transmission at UIUC and has prevented spread to the larger community.

A Saliva-Based Diagnostic Test for SARS-CoV-2 that Bypasses RNA Isolation, and its Use in Mitigating Viral Transmission at a Large Public University

ACS Spring Meeting 2021

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