AUTHOR=Nacher Mathieu , Mergeay-Fabre Mayka , Blanchet Denis , Benoit Orelie , Pozl Tristan , Mesphoule Pauline , Sainte-Rose Vincent , Vialette Véronique , Toulet Bruno , Moua Aurélie , Saout Mona , Simon Stéphane , Guidarelli Manon , Galindo Muriel , Biche Barbara , Faurous William , Chaizemartin Laurie , Fahrasmane Aniza , Rochemont Devi , Vignier Nicolas , Vabret Astrid , Demar Magalie TITLE=Prospective Comparison of Saliva and Nasopharyngeal Swab Sampling for Mass Screening for COVID-19 JOURNAL=Frontiers in Medicine VOLUME=8 YEAR=2021 URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2021.621160 DOI=10.3389/fmed.2021.621160 ISSN=2296-858X ABSTRACT=

Current testing for COVID-19 relies on reverse-transcriptase polymerase chain reaction from a nasopharyngeal swab specimen. Saliva samples have advantages regarding ease and painlessness of collection, which does not require trained staff and may allow self-sampling. We enrolled 776 persons at various field-testing sites and collected nasopharyngeal and pooled saliva samples. One hundred sixty two had a positive COVID-19 RT-PCR, 61% were mildly symptomatic and 39% asymptomatic. The sensitivity of RT-PCR on saliva samples vs. nasopharygeal swabs varied depending on the patient groups considered or on Ct thresholds. There were 10 (6.2%) patients with a positive saliva sample and a negative nasopharyngeal swab, all of whom had Ct values <25 for three genes. For symptomatic patients for whom the interval between symptoms onset and sampling was <10 days sensitivity was 77% but when excluding persons with isolated N gene positivity (54/162), sensitivity was 90%. In asymptomatic patients, the sensitivity was only 24%. When we looked at patients with Cts <30, sensitivity was 83 or 88.9% when considering two genes. The relatively good performance for patients with low Cts suggests that Saliva testing could be a useful and acceptable tool to identify infectious persons in mass screening contexts, a strategically important task for contact tracing and isolation in the community.