Concordance between PCR-based extraction-free saliva and nasopharyngeal swabs for SARS-CoV-2 testing

Chiara De Santi , Benson Jacob , Patricia Kroich , Sean Doyle, Rebecca Ward , Brian Li , Owain Donnelly,  Amy Dykes , Trisha Neelakant , David Neary , Ross McGuiness , Jacqueline Cafferkey , Kieran Ryan , Veronica Quadu , Killian McGrogan , Alejandro Garcia Leon , Patrick Mallon , Fidelma Fitzpatrick , Hilary Humphreys , Eoghan De Barra , Steve Kerrigan,  Gianpiero L Cavalleri 

Saliva represents a less invasive alternative to nasopharyngeal swab (NPS) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection. SalivaDirect is a nucleic acid extraction-free method for detecting SARS-CoV2 in saliva specimens. Studies evaluating the concordance of gold standard NPS and newly developed SalivaDirect protocols are limited. The aim of our study was to to assess SalivaDirect as an alternative method for COVID-19 testing. Methods: Matching NPS and saliva samples were analysed from a cohort of symptomatic (n=127) and asymptomatic (n=181) participants recruited from hospital and university settings, respectively. RNA was extracted from NPS while saliva samples were subjected to the SalivaDirect protocol before RT-qPCR analysis. The presence of SARS-Cov-2 was assessed using RdRP and N1 gene targets in NPS and saliva, respectively. See full publication here.