Natural spring water gargle and direct RT-PCR for the diagnosis of COVID-19 (COVID-SPRING study)

• DOI: 10.1016/j.jcv.2021.104995
• Publication Date: 2021-10-04T12:51:55Z
• Authors: Jeannot Dumaresq; François Coutlée; Philippe J. Dufresne; Jean Longtin; Judith Fafard; Julie Bestman-Smith; Marco Bergevin; Emilie Vallières; Marc Desforges; Annie-Claude Labbé
• Keywords: Reverse Transcriptase Polymerase Chain Reaction; SARS-CoV-2; COVID-19; Water; Article; Specimen Handling; 3. Good health; 03 medical and health sciences; 0302 clinical medicine; Nasopharynx; Humans; RNA, Viral; Saliva

AbstractWe prospectively compared natural spring water gargle to combined oro-nasopharyngeal swab (ONPS) for the diagnosis of coronavirus disease 2019 (COVID-19) in paired clinical specimens (1005 ONPS and 1005 gargles) collected from 987 unique early symptomatic as well as asymptomatic individuals from the community. Using a direct RT-PCR method with the Allplex™ 2019-nCoV Assay (Seegene), the clinical sensitivity of the gargle was 95.3% (95% confidence interval [CI], 90.2 to 98.3%) and was similar to the sensitivity of the ONPS (93.8%; 95% CI, 88.2 to 97.3%), despite significantly lower viral RNA concentration in gargles, as reflected by higher cycle threshold values. No single specimen type detected all COVID-19 cases. SARS-CoV-2 RNA was stable in gargles at room temperature for at least 7 days. The simplicity of this sampling method coupled with the accessibility of spring water are clear advantages in a pandemic situation where testing frequency, turnaround time and shortage of consumables and trained staff are critical elements.