Saliva as a testing sample for SARS-CoV-2 detection by RT-PCR in low prevalence community settings

There is an urgency for the rapid and simple SARS-CoV-2 detection method. Our study aimed to demonstrate that saliva can be used as a specimen for SARS-CoV-2 detection notably for the screening of extensive population groups via pooling. We collected paired nasopharyngeal/oropharyngeal swabs (NPS) and saliva and performed 36 serial measurements of 8 SARS-CoV-2 positive saliva samples to confirm the stability of the specimen. We also completed 37 pools by adding one positive saliva specimen per pool. A field study including 3,660 participants was performed between September 29 and October 1, 2020. Saliva specimens were stable for testing for up to 24 hours. Overall, 1.2% of the saliva samples tested positive for SARS-CoV-2. The results of saliva samples were consistent with those obtained from NPS with 90% sensitivity (95% CI 68.3%-98.7%) and 100% specificity during the first two weeks after the onset of symptoms. All pools showed 100% positivity in different pooling proportions. Our findings demonstrate that saliva is an appropriate specimen for pooling and SARS-CoV-2 screening with accurate diagnostic performance. Patient-performed specimen collection allows testing an extensive number of people rapidly, obtaining results of the spread of SARS-CoV-2 and allowing authorities to take timely measures.