ABSTRACT
The use of saliva for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sparks debate due to presumed lower sensitivity and lack of standardization. Our aim was to evaluate the performance characteristics of (i) saliva collected by the ORAcollectTM device as a matrix for SARS-CoV-2 reverse-transcriptase polymerase chain reaction (RT-PCR), and (ii) 2 saliva rapid antigen tests (AgRDT). From 342 ambulatory individuals, both a nasopharyngeal swab and saliva sample via ORAcollectTM were obtained for a SARS-CoV-2 RT-PCR test. Furthermore, 54 and 123 additionally performed the V-ChekTM or WhistlingTM saliva AgRDT. In total, 35% of individuals screened positive for SARS-CoV-2 via nasopharyngeal swab. Saliva, as a matrix for the RT-PCR, had a specificity of 96.5% and a negative predictive value (NPV) of 91.3%. Interestingly, 6 out of 8 patients thought to be false positive in saliva re-tested positive by nasopharyngeal sampling after 2 to 9 days. Both V-ChekTM and WhistlingTM AgRDT had a lack of sensitivity, resulting in an NPV of 66.9 and 67.3%, respectively. Saliva proved to be a sensitive and specific matrix for SARS-CoV-2 detection by the RT-PCR. In this setting, saliva might have an earlier window of detection than the nasopharyngeal swab. By contrast, both AgRDT showed an unacceptably low sensitivity and NPV.
Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19 Testing , Clinical Laboratory Techniques/methods , Humans , Nasopharynx , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , Saliva , Sensitivity and Specificity , Specimen Handling/methodsABSTRACT
Presence of SARS-CoV-2 was monitored in nasopharyngeal samples from young children aged 6-30 months attending day-care centres (DCCs) in Belgium from May 2020-February 2022. SARS-CoV-2 carriage among DCC children was only detected from November 2021, after emergence of Delta and Omicron variants, in 9 of the 42 DCCs screened. In only one DCC, two children tested positive for SARS-CoV-2 at the same sampling time point, suggesting limited transmission of SARS-CoV-2 in Belgian DCCs among young children during the studied period.