Saliva as a potential clinical specimen for diagnosis of SARS-CoV-2

Abstract

Background It is almost nine months, still there is no sign to stop the spreading of the COVID-19 pandemic. Rapid and early detection of the virus is the master key to cease the rapid spread and break the human transmission chain. There are very few studies in search of an alternate and convenient diagnostic tool which can substitute nasopharyngeal swab (NPS) specimen for detection of SARS-CoV-2. We aimed to analyse the comparison and agreement between the feasibility of using the saliva in comparison to NPS for diagnosis of SARS-CoV-2. Methods A total number of 74 patients were enrolled for this study. We analysed and compared the NPS and saliva specimen collected within 48 h after the symptom onset. We used real time quantitative polymerase chain reaction (RT-qPCR), gene sequencing for the detection and determination SARS-CoV-2 specific genes. Phylogenetic tree was constructed to establish the isolation of viral RNA from saliva. We use Bland-Altman model to identify the agreement between two sampling methods. Findings This study shows a lower CT mean value for the detection of SARS-CoV-2 ORF1 gene (27.07; 95% CI, 25.62 to 28.52) in saliva methods than that of NPS (28.24; 95% CI, 26.62 to 29.85) sampling method. Bland-Altman analysis produces relatively smaller bias and high agreement between these specimen tools. Phylogenetic analysis with the RdRp and Spike gene confirmed the presence of SARS-CoV-2 in the saliva samples. Interpretation: In conclusion, our study highlights that saliva represents a promising tool in COVID-19 diagnosis and would reduce the exposure risk of frontline health workers which is one of biggest concern in primary healthcare settings.

Performance of Saliva, Oropharyngeal Swabs, and Nasal Swabs for SARS-CoV-2 Molecular Detection: a Systematic Review and Meta-analysis

“…We also assessed if patient symptomatology could explain variable diagnostic performance between saliva and NP sampling. We found that only a few studies provided a direct comparison between asymptomatic ( 16 , 19 , 33 ) and symptomatic patient data ( 17 , 18 , 21 – 23 , 25 , 27 , 28 , 34 , 35 , 37 , 39 , 40 ) that could be parsed and extracted for analysis. We found that % positive saliva was similar between asymptomatic and symptomatic patients (87% [95% CI 70 to 98%] versus 88% [95% CI 79 to 95%], respectively).…”

Diagnostic performance of different sampling approaches for SARS-CoV-2 RT-PCR testing: a systematic review and meta-analysis

“…On the basis of our selection criteria, 127 of those studies were excluded and 23 studies 21 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 met our inclusion criteria ( table ). Of these, 14 studies were from the USA, 21 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 four were from European countries, 60 , 61 , 62 , 63 two were from Eastern Mediterranean countries, 64 , 65 and the rest were from Canada, 66 India, 67 and China. 68 7973 individuals with suspected SARS-CoV-2 infection, who were mostly symptomatic outpatients presenting to dedicated testing sites or emergency departments, were included from the 23 eligible studies.…”

Saliva‐based testing for diagnosis of SARS‐CoV‐2 infection: A meta‐analysis

“…Fourteen studies (16 cohorts) were included. [6][7][8][9][10][11][12][13][14][15][16][17][18][19] A total number of patients for sensitivity and specificity comparison was 5863 (median:158; interquartile range: 94-234) (Table S1). Mean or median age of patients ranged from 33.5 to 44.9 years in six studies (seven cohorts) where information was available, and three studies included some pediatric patients.…”