The Use of Saliva as a Diagnostic Specimen for SARS CoV-2 Molecular Diagnostic Testing for Pediatric Patients

Abstract

BackgroundChildren are an important population to test for COVID-19 infection, particularly because they may shed the virus without displaying symptoms. Testing children for COVID-19 via sensitive molecular methods is important, although collecting nasopharyngeal (NP) specimens can be challenging. A less invasive mode of specimen collection that yields test results comparable to those from NP specimens would be beneficial to simplify sample collection.MethodsTo demonstrate that saliva is a suitable specimen for collection from children, the clinical usability/acceptability and the analytic performance of saliva were compared to NP specimens suspended in viral transport medium. Four different FDA EUA-approved real-time RT-PCR assays and one EUA approved saliva collection device were investigated.ResultsThe study population included 526 patients between the ages of 3 and 61 years, 461 (88%) were <18 years, 425 were asymptomatic (81.1%), 92 were symptomatic (17.6%). Saliva mixed with saliva stabilizing buffer was found to yield comparable sensitivity to NP specimens when tested on the AllPlex SARS-CoV-2 molecular test (Seegene Inc). The analytic sensitivity of the AllPlex assay during testing of spiked saliva mixed with SpectrumDNA saliva stabilizer was found to be 250 genomic copies/mL.ConclusionsOf the four FDA EUA-approved SARS-CoV-2 PCR assays studied, we found the AllPlex assay to be best suited for testing saliva specimens collected from children 5 years of age or older. The sensitivity of viral detection was equivalent to NP specimens when saliva specimens were mixed with the saliva stabilizer.

The accuracy of saliva versus nasopharyngeal and/or oropharyngeal samples for the detection of SARS-CoV-2 in children – A rapid systematic review and meta-analysis

“…103 papers were retained and assessed for full-text eligibility and 89 papers were excluded as they did not include children (individuals aged <18 years). Out of the 14 papers [8][9][10][11][12][13][14][15][16][17][18][19][20][21] which fulfilled our eligibility criteria, we requested additional accuracy data for 9 papers of which we obtained 5. The final 10 8,10-17,21 studies included in the meta-analysis comprised 5 studies for which data was received from authors and 5 studies where data was available in the original article.…”

“…The remaining six studies included both asymptomatic and symptomatic patients, but only one study 17 provided stratified data based on symptom status. All of the studies utilised nasopharyngeal swabs collected by healthcare workers as the comparator test except for two studies 10,14 which included nasopharyngeal and/or oropharyngeal swabs. Different techniques for saliva collection were used: general spitting technique in 5 studies 8,11,12,15,21 , drooling method in one study 13 , posterior oropharyngeal spitting technique (by asking children to clear their throats thoroughly and collect saliva) in one study 17 and 3 studies did not report the saliva collection technique 10,14,16 .…”

“…All of the studies utilised nasopharyngeal swabs collected by healthcare workers as the comparator test except for two studies 10,14 which included nasopharyngeal and/or oropharyngeal swabs. Different techniques for saliva collection were used: general spitting technique in 5 studies 8,11,12,15,21 , drooling method in one study 13 , posterior oropharyngeal spitting technique (by asking children to clear their throats thoroughly and collect saliva) in one study 17 and 3 studies did not report the saliva collection technique 10,14,16 . In addition to the usual saliva collection, one study collected saliva after oropharyngeal washing 12 (where patients were asked to gargle 2ml of saline solution 1-2 minutes prior to saliva collection).…”

“…Although saliva collection is more comfortable than NPS sampling in children, obtaining an appropriate saliva specimen still can be challenging, particularly among infants. Delaney et al 10 reported that 2% of patients were unable to provide sufficient volume (1-2ml) of saliva for testing. The authors recommended the age cut off of five years and older for saliva sampling as many of those younger than five were unable to provide saliva samples for testing.…”

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

“…Thus we were not able to test our approach in two key demographics: elderly individuals (>65 years of age) who are the most at risk for disease and school-aged children (<18 years of age) who critically need testing to help support in-person learning, though others have recently demonstrated that saliva is a suitable specimen for pediatric testing. 64 Moreover, including professional athletes in our trial of repeat SARS-CoV-2 screening may not be representative of the general population, and we will therefore continue to monitor any laboratories using SalivaDirect for asymptomatic screening.…”