ABSTRACT
BackgroundRT-PCR of nasopharyngeal swabs (NPS) is the acknowledged gold standard for the detection of SARS-CoV-2 infection. Rising demands for repetitive screens and mass-testing necessitate, however, the development of additional test strategies. Saliva may serve as an alternative to NPS as its collection is simple, non-invasive and amenable for mass- and home-testing but rigorous validation of saliva particularly in children is missing. MethodsWe conducted a large-scale head-to-head comparison of SARS-CoV-2 detection by RT-PCR in saliva and nasopharyngeal swab (NPS) of 1270 adults and children reporting to outpatient test centers and an emergency unit for an initial SARS-CoV-2 screen. The saliva collection strategy developed utilizes common, low-cost plastic tubes, does not create biohazard waste at collection and was tailored for self-collection and suitability for children. ResultsIn total, 273 individuals were tested SARS-CoV-2 positive in either NPS or saliva. SARS-CoV-2 RT-PCR results in the two specimens showed a high agreement (Overall Percent Agreement = 97.8%). Despite lower viral loads in saliva of both adults and children, detection of SARS-CoV-2 in saliva compared well to NPS (Positive Percent Agreement = 92.5%). Importantly, in children, SARS-CoV-2 infections were more often detected in saliva than NPS (Positive Predictive Value = 84.8%), underlining that NPS sampling in children can be challenging. ConclusionsThe comprehensive parallel analysis reported here establishes saliva as a generally reliable specimen for the detection of SARS-CoV-2 with particular advantages for testing children that is readily applicable to increase and facilitate repetitive and mass-testing in adults and children. Article Summary Main PointsComparison with nasopharyngeal swabs in a large test center-based study confirms that saliva is a reliable and convenient material for the detection of SARS-CoV-2 by RT-PCR in adults and increases detection efficacy in children.
