SalivaDirect: A simplified and flexible platform to enhance SARS-CoV-2 testing capacity

A.L. Wyllie, C.B.F. Vogels, O. Allicock, A.E. Watkins, M.E. Petrone, D. Yolda Carr, C.A. Harden, D.E. Brackney, C.C. Kalinich, M. Breban, I.M. Ott, R. Sikka, L. Kadiri, N.D. Grubaugh
Yale School of Public Health,
United States

Keywords: saliva, COVID-19, SARS-CoV-2, screening, surveillance, diagnostics


Background. Quickly detecting and isolating individuals positive for SARS-CoV-2 is essential for limiting virus spread. Policy makers rely on the number of active cases to make decisions, and individuals use this information to evaluate risk should they return to public spaces. Robust testing strategies have been plagued with limited authorized diagnostic assays and high test prices, with large-scale implementation hampered by worldwide supply chain issues. Methods. Having identified its potential early in the pandemic, we simplified saliva-based COVID-19 diagnostic testing by (1) not requiring collection tubes with preservatives, (2) replacing nucleic acid extraction with a simple enzymatic and heating step, and (3) testing specimens for SARS-CoV-2 in dualplex RT-qPCR. Moreover, we validated this approach (“SalivaDirect”) with reagents and instruments from multiple vendors to circumvent supply chain disruptions. Results. SalivaDirect’s simplified protocol does not compromise on sensitivity. In our hospital cohort, we found a high positive agreement (94%) between saliva tested with SalivaDirect and nasopharyngeal swabs tested with a commercial RT-qPCR kit. With the National Basketball Association we tested 3,779 saliva specimens from healthy individuals and detected low rates of invalid (0.3%) and false-positive (