key: cord-0798767-0bbzo9cp authors: Pasomsub, Ekawat; Watcharananan, Siriorn P.; Boonyawat, Kochawan; Janchompoo, Pareena; Wongtabtim, Garanyuta; Suksuwan, Worramin; Sungkanuparph, Somnuek; Phuphuakrat, Angsana title: Saliva Sample as a Non-Invasive Specimen for the Diagnosis of Coronavirus Disease-2019 (COVID-19): a Cross-Sectional Study date: 2020-04-22 journal: nan DOI: 10.1101/2020.04.17.20070045 sha: ac6c0caab3f814f5267a62c2569da6cbd79fad57 doc_id: 798767 cord_uid: 0bbzo9cp Objectives. Amid the increasing number of global pandemic coronavirus disease 2019 (COVID-19) cases, there is a need for a quick and easy method to obtain a non-invasive sample for the detection of this novel coronavirus 2019 (SARS-CoV-2). We aimed to investigate the potential use of saliva samples as a non-invasive tool for the diagnosis of COVID-19. Methods. From 27 March to 4 April, 2020, we prospectively collected saliva samples and a standard nasopharyngeal and throat swab in persons seeking care at an acute respiratory infection clinic in a university hospital during the outbreak of COVID-19. Real-time polymerase chain reaction (RT-PCR) was performed, and the results of the two specimens were compared. Results. Two-hundred pairs of the samples were collected. Sixty-nine (34.5%) patients were male, and the median (interquartile) age was 36 (28-48) years. Using nasopharyngeal and throat swab RT-PCR as the reference standard, the prevalence of COVID-19 diagnosed by nasopharyngeal and throat swab RT-PCR was 9.5%. The sensitivity and specificity of the saliva sample RT-PCR were 84.2% [95% confidence interval (CI) 79.2%-89.3%], and 98.9% (95% CI 97.5-100.3%), respectively. An analysis of the agreement between the two specimens demonstrated 97.5% observed agreement (kappa coefficient 0.851, 95% CI 0.723-0.979; p <0.001). Conclusions. Saliva specimens can be used for the diagnosis of COVID-19. The collection method is non-invasive, and non-aerosol generating. Using a saliva sample as a specimen for the detection of SARS-CoV-2 could facilitate the diagnosis of the disease, which is one of the strategies that helps in controlling the epidemic. Since December 2019, the outbreak of coronavirus disease 2019 (COVID-19), caused 53 by the novel coronavirus 2019 (SARS-CoV-2) has emerged in Hebei Province of China and 54 has spread to other parts of the world [1, 2] . The number of cases has been increasing rapidly, 55 with a case-fatality rate of 2.3% [3] . 56 Detection of SARS-CoV-2 in patient specimens is the first crucial step for the 57 guidance of treatment, effective infection control in the hospital and control of infection in 58 the community. Screening of infection in suspected cases with a nucleic acid amplification 59 test (NAAT), such as real-time polymerase chain reaction (RT-PCR), in respiratory 60 specimens, is recommended by the World Health Organization [4] . However, the collection 61 of nasopharyngeal and/or oropharyngeal swab specimens is a relatively invasive method and 62 the procedure might put healthcare workers at higher risk for disease transmission during 63 patients' gag reflex, cough, or sneezing. 64 As SARS-CoV-2 viral load was demonstrated to present near presentation onset [5] , 65 using a saliva sample as the specimen for the screening of the disease is appealing. To 66 determine the potential of using a saliva sample for the diagnosis of COVID-19, we 67 conducted a prospective study investigating the correlation of detection of SARS-CoV-2 in a 68 saliva sample, and nasopharyngeal and throat swabs in patients under investigation at an 69 acute respiratory infection clinic at a university hospital in Bangkok, Thailand during the 70 The detection of SARS-CoV-2 in the specimens was performed by real-time RT-PCR 97 amplification of SARS-CoV-2 ORF1AB and N gene fragments, using a SARS-CoV-2 98 Nucleic Acid Diagnostic Kit (Sansure Biotech) which was approved for detection of the 99 SARS-CoV-2 by the National Medical Products Administration (NMPA) and certified by the 100 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. presented in Table 1 . The prevalence of COVID-19 diagnosed by nasopharyngeal and throat 124 swab RT-PCR, and saliva RT-PCR in this study were 9.5% and 9.0%, respectively. 125 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 22, 2020. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 22, 2020. Previous experimental studies showed a higher level of ACE2 expression in minor salivary 151 glands, as compared to that in the lungs [9] and that the epithelial cells lining salivary gland 152 was also detected in saliva samples [11] . This suggested that the salivary glands could be a 154 potential target for SAR-CoV-2 infection, and hence saliva could be a potential sample for 155 SARS-CoV-2 detection. 156 From recent findings, SARS-CoV-2 was detected from posterior oropharyngeal saliva 157 samples, with a notable high viral load at the disease presentation. [5, 12] . In their protocol, 158 an early morning saliva was collected after coughing up by clearing the throat. In our study, a 159 saliva sample was the patient's self-generated, without a need for coughing up. This non-160 invasive procedure might be less aerosol-generating and might reduce the risk of infection for 161 health care workers working in the clinic. 162 Although testing of saliva might provide an advantage as an easy procedure, a 163 comparison study between saliva and confirmed case of bronchoalveolar lavage (BAL) fluid 164 or convalescence serum titre has not been available. A recent study that detected the virus 165 from multiple sites showed a lower test positivity rate from the nasal swab (63%), as 166 compared to the bronchoalveolar lavage fluid (93%) [13] . Therefore, a false negative test of 167 the SARS-CoV-2 from saliva sample might possible, and this would be an area for further 168 exploration. However, the spectrum of the disease ranges from asymptomatic, upper 169 respiratory tract symptoms, pneumonia, and acute respiratory distress syndrome [14, 15] . 170 Hence, the discrepancy of SARS-CoV-2 detection from different specimens might also be 171 possible. 172 The study had several strengths. We prospectively collected data on consecutive 173 patients who were at high risk of COVID-19 infection including those with acute respiratory 174 symptoms and having risk factors, thus minimizing potential spectrum effect. All enrolled 175 . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 22, 2020. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted April 22, 2020. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted April 22, 2020. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) The copyright holder for this preprint this version posted April 22, 2020. . https://doi.org/10.1101/2020.04.17.20070045 doi: medRxiv preprint A familial cluster of 201 pneumonia associated with the 2019 novel coronavirus indicating person-to-person 202 transmission: a study of a family cluster Clinical features of patients 204 infected with 2019 novel coronavirus in Wuhan, China Coronavirus Disease 2019 in China World Health Organization. Laboratory testing for 2019 novel coronavirus (2019-209 nCoV) in suspected human cases 2020 Temporal profiles of 213 viral load in posterior oropharyngeal saliva samples and serum antibody responses 214 during infection by SARS-CoV-2: an observational cohort study Laboratory diagnosis of emerging human coronavirus 217 infections -the state of the art Interrater reliability: the kappa statistic SARS-CoV-2 Cell Entry Depends on ACE2 and TMPRSS2 and Is Asymptomatic Infection