Feasibility and accuracy of a novel saliva sampling method for large-scale SARS-CoV-2 screening in children < 12 years of age

Children have been disproportionately affected during the COVID-19 pandemic. We aimed to assess a saliva-based algorithm for SARS-CoV-2 testing to be used in schools and childcare institutions under pandemic conditions. A weekly SARS-CoV-2 sentinel study in primary schools, kindergartens and childcare facilities was conducted over a 12-week-period. In a sub-study covering 7 weeks, 1895 paired oropharyngeal and saliva samples were processed for SARS-CoV-2 rRT-PCR testing in both asymptomatic children (n=1243) and staff (n=652). Forty-nine additional concurrent swab and saliva samples were collected from SARS-CoV-2 infected patients (patient cohort). The Salivette(R) system was used for saliva collection and assessed for feasibility and diagnostic performance. For children a mean of 1.18 ml saliva could be obtained. Based on results from both cohorts, the Salivette(R) testing algorithm demonstrated specificity of 100% (95% CI 99.7 - 100) and sensitivity of 94.9% (95% CI 81.4 - 99.1) with oropharyngeal swabs as reference. Agreement between sampling systems was 100% for moderate to high viral load situations (defined as Ct-values < 33 from oropharyngeal swabs). Comparative analysis of Ct-values derived from saliva vs. oropharyngeal swabs demonstrated a significant difference (mean 4.23; 95% CI 2.48-6.00). In conclusion, the Salivette(R) system proved to be an easy-to-use, safe and feasible saliva collection method and a more pleasant alternative to oropharyngeal swabs for SARS-CoV-2 testing in children aged 3 years and above.