Performance of RT-PCR on saliva specimens compared to nasopharyngeal swabs for the detection of SARS-CoV-2 in children: A prospective comparative clinical trial

Y. Fougère, J. Schwob, A. Miauton, F. Hoegger, O. Opota, K. Jaton, R. Brouillet, Gilbert GREUB, B. Genton, M. Gehri, I. Taddeo, V. D'Acremont, S. Asner

medRxiv, 2021

Background: Saliva RT-PCR is an attractive alternative for the detection of SARS-CoV-2 in adults with much less known in children. Methods: Children and adolescents with symptoms suggestive of COVID-19 were prospectively enrolled in a comparative clinical trial of saliva and nasopharyngeal (NP) RT-PCR between November and December 2020. Detection rates and sensitivities of saliva and NP RT-PCR were compared. Participants with discordant NP and saliva RT-PCR results including viral load (VL) were also analyzed. Result: Out of 405 patients enrolled, 397 patients had two tests performed. Mean age was 12.7 years (range 1.2-17.9). Detection rates were 22.9% (95%CI 18.8-27.1%) by saliva RT-PCR, 25.4% (21.2-29.7%) by NP RT-PCR, and 26.7% (22.4-31.1%) by any test. The sensitivity of saliva was 85.2% (78.2-92.1%) when using NP as the gold standard; in contrast, when saliva was considered the gold standard, the sensitivity of NP was 94.5% (89.8-99.2%).For a NP RT-PCR VL threshold of [≥]103 and [≥]104 copies/ml, sensitivity of saliva increases to 88.7% and 95.2% respectively. Sensitivity of saliva and NP swabs was respectively 89.5% and 95.3% in patient with symptoms less than 4 days (p=0.249) and 70.0% and 95.0% in those with symptoms [≥] 4 to 7 days (p=0.096). The 15 patients who had an isolated positive NP RT-PCR were significantly younger (p=0.034), had a lower NP VL (median 5.6x103 vs 3.9x107, p<0.001), and were not able to drool saliva at the end of the sampling (p=0.002). VLs were significantly lower with saliva PCR than with NP RT-PCR (median 8.7 cp/ml x104; IQR 1.2x104-5.2x105; vs median 4.0x107cp/ml; IQR 8.6x105-1.x108; p<0.001). Conclusion: Saliva PCR shows diagnostic performances close to NP RT-PCR for SARS-CoV2 detection in most symptomatic outpatient children and adolescents.

Cited by 4 publications.

Field of study: Medicine

10.1101/2021.02.27.21252571