key: cord-0954335-klokhpkf
authors: Felix, A. C.; De Paula, A. V.; Ribeiro, A. C.; Inemami, M.; Costa, A. A.; Leal, C. O. D.; Figueiredo, W. M.; Sarmento, D. J. S.; Sassaki, T. A.; Pannuti, C. S.; Braz-Silva, P. H.; Romano, C. M.
title: Saliva as a Reliable Sample for COVID-19 Diagnosis in Paediatric Patients
date: 2021-03-31
journal: nan
DOI: 10.1101/2021.03.29.21254566
sha: 77c51f86cd00bb5178c313242d344c8cd9640243
doc_id: 954335
cord_uid: klokhpkf

Saliva has been described a less invasive and easy to handle sample, compared to nasopharyngeal swabs (NPS), in the diagnosis of COVID-19 in adults. Although the advantages of using saliva is still more evident in paediatric patients, little is now about its sensitivity in this group. The aim of this study was to compare the performance of saliva to that of NPS in the detection of SARS-CoV-2 in paediatric patients with mild symptoms. This study evaluated saliva samples from children with suspected COVID-19 who attended public healthcare services of Araraquara, Sao Paulo, Brazil. Children were asked to spit into a sterile container for collection of about 1ml of saliva after the NPS collection. SARS-COV-2 detection was performed by using the Altona RealStar SARS-CoV-2 RT-PCR Kit 1.0. The sample consisted of 50 patients, in which 27 were girls (54%) and 23 were boys (46%). Ten were positive for SARS-CoV-2 in at least one sample collected. The mean age was 10.24 years old and saliva was collected after 4.76 days from the symptoms. Saliva and NPS have showed the same performance in the SARS-CoV-2 detection (k = 0.865, P < 0.001). In conclusion, saliva is a reliable alternative sample for COVID-19 diagnosis in paediatric population.

Romano conceptualized and designed the study, coordinated and supervised the data collection, draft the manuscript and critically reviewed the manuscript for important intellectual content. All authors approved the final manuscript as submitted and agreed to be accountable for all aspects of the work. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 31, 2021. ; https://doi.org/10.1101/2021.03.29.21254566 doi: medRxiv preprint NOTE: This preprint reports new research that has not been certified by peer review and should not be used to guide clinical practice.

. CC-BY-NC-ND 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 31, 2021. ; https://doi.org/10.1101/2021.03.29.21254566 doi: medRxiv preprint Abstract Saliva has been described a less invasive and easy to handle sample, compared to nasopharyngeal swabs (NPS), in the diagnosis of COVID-19 in adults. Although the advantages of using saliva is still more evident in paediatric patients, little is now about its sensitivity in this group. The aim of this study was to compare the performance of saliva to that of NPS in the detection of SARS-CoV-2 in paediatric patients with mild symptoms. This study evaluated saliva samples from children with suspected COVID-19 who attended public healthcare services of Araraquara, São Paulo, Brazil. Children were asked to spit into a sterile container for collection of about 1ml of saliva after the NPS collection. SARS-COV-2 detection was performed by using the Altona RealStar® SARS-CoV-2 RT-PCR Kit 1.0. The sample consisted of 50 patients, in which 27 were girls (54%) and 23 were boys (46%). Ten were positive for SARS-CoV-2 in at least one sample collected. The mean age was 10.24 ± 3.52 years old and saliva was collected after 4.76 ± 1.31 days from the symptoms. Saliva and NPS have showed the same performance in the SARS-CoV-2 detection (k = 0.865, P < 0.001). In conclusion, saliva is a reliable alternative sample for COVID-19 diagnosis in paediatric population. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

Massive testing is one of the most effective strategies for preventing COVID-19 transmission by allowing early identification of cases and decision-making based on the pandemic's behaviour 1 . Nasopharyngeal swab (NPS) is the standard sample for molecular test, which causes much discomfort and possible cross-contamination during the collection 1,2 . Therefore, a trained healthcare professional is required for performing this procedure 1,3 . Saliva has been shown to be a reliable, safe diagnostic fluid for detection of SARS-CoV-2, with a sensitivity ranging from 80-100% compared to NPS in adult population 1, 3, 4 . In paediatrics, the use of saliva has clear advantages because the collection of this fluid is less invasive, thus reducing the discomfort and allowing self-collection 2 .

The objective of the present study was to compare the performance of saliva to that of NPS in the detection of SARS-CoV-2 in paediatric patients with mild symptoms.

This study evaluated saliva samples from children with suspected COVID-19 who attended public healthcare services of Araraquara, which is a medium-sized city located in the State of São Paulo, with a population of 238,339 in 2020.

As part of the COVID-19 contingency plan, the city of Araraquara offers molecular tests for detection of SARS-COV-2 by using NPS in all symptomatic patients seeking healthcare service. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 31, 2021. ; https://doi.org/10.1101/2021.03.29.21254566 doi: medRxiv preprint until being taken to the laboratory (< 48 hours). Symptoms and delay between their onset and sample collection (days) were also recorded. Total RNA was extracted by using the viral RNA mini kit (Qiagen, GE) and SARS-COV-2 detection was made by using the 

The sample consisted of 50 patients, in which 27 were girls (54%) and 23 were boys (46%). Ten were positive for SARS-CoV-2 in at least one sample collected (saliva or NPS). The mean age was 10.24 ± 3.52 years old and saliva was collected after 4.76 ± 1.31 days from the symptoms. Of the 50 patients evaluated, symptoms were reported by 46 during the saliva collection and the main ones were the following: coryza (60.9%), cough (56.5%), sore throat (45.7%), headache (39.1%) and fever (30.4%). None of these symptoms was statistically associated with the diagnosis of COVID-19 (Table 1) .

ROC curve analysis was performed in order to assess sensitivity and specificity of RT-PCR between saliva and NPS, with the latter being considered a gold standard test.

The results showed a statistically significant curve (AUC = 0.851, SE = 0.094; P = 0.002; 95% CI = 0.667 -1.00). With these results, we can state that saliva can be safely used for diagnosis of COVID-19 in paediatric patients. We also tested the concordance between saliva and NPS by using Kappa concordance test (k = 0.702; P < 0.001), with 92% of the . CC-BY-NC-ND 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 31, 2021. ; https://doi.org/10.1101/2021.03.29.21254566 doi: medRxiv preprint samples being concordant (Table 2) . Additionally, the concordance between these fluids was assessed individually, in which positive cases (10/50 patients) were considered as true infection. It was observed that the saliva and NPS showed the same values for Kappa concordance test (k = 0.865, P < 0.001).

Consistent scientific evidence has pointed to the effectiveness of the use of saliva as a diagnostic fluid for COVID-19 in adult population 1, 3, 4 . The advantages of a less invasive and painless sample collection have been shown to be more evident in paediatric population, which may include self-collection and multiple collection possibilities 2 .

However, there are a few studies of paediatric patients and different ways to sampling for SARS-CoV-2 detection and their results are conflicting [5] [6] [7] . Our results showed that saliva had the same diagnostic performance than that of NPS for SARS-CoV-2.

The use of less invasive strategies for COVID-19 surveillance has a crucial importance for children not only in the understanding of SARS-CoV-2 behavior in this population, but also in the re-opening of schools based on constant tracking of asymptomatic cases 2,6 . Additionally, with the emergence of the variants of concern and vaccination campaigns were initially not aimed at this age group, saliva could help on the detection of them in paediatric patients. The use of saliva makes COVID-19 surveillance viable, since this strategy is more largely accepted by individuals for being painless and for requiring no professional sample collection 2,3 . Depending on the age group, the individuals themselves can be remotely instructed (e.g. videos) to perform the sample collection 3 . is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted March 31, 2021. ; https://doi.org/10.1101/2021.03.29.21254566 doi: medRxiv preprint

The limitations of this preliminary work are in the fact that larger samples and inclusion of asymptomatic children should be considered in further studies.

Our data allow us to conclude that saliva is a viable alternative fluid for molecular diagnosis of COVID-19 in children.

COVID-19 salivary signature: diagnostic and research opportunities

Saliva: an important alternative for screening and monitoring of COVID-19 in children

Performance of at-home self-collected saliva and nasal-oropharyngeal swabs in the surveillance of COVID-19

Consistent Detection of 2019 Novel Coronavirus in Saliva

Clinical Utility of Buccal Swabs for Severe Acute Respiratory Syndrome Coronavirus 2

Detection in Coronavirus Disease 2019-Infected Children

Saliva viral load better correlates with clinical and immunological profiles in children with

It is made available under a perpetuity.is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprintThe copyright holder for this this version posted March 31, 2021. ; https://doi.org/10.1101/2021.03.29.21254566 doi: medRxiv preprint