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

Abstract

Objectives Children have been disproportionately affected during the COVID-19 pandemic. Novel test strategies are urgently needed to ensure safe operation of schools and childcare institutions and to avoid prolonged closures. Methods A weekly SARS-CoV-2 sentinel study in primary schools, kindergartens and childcare facilities over a 12 week period was conducted. In total, 3123 concurrent oropharyngeal and saliva samples were processed for SARS-CoV-2 rRT-PCR testing in both children (n=2104) and staff (n=1019). Saliva sampling was optimised, and a novel sampling system was introduced and assessed for feasibility, the Salivette system. Results For children across all age groups a mean of 1,18 ml saliva could be obtained with this easy-to-handle system. Using 1293 concurrent oropharyngeal swabs from children, staff and participants of a positive control cohort as reference, the Salivette testing method could be assigned an overall specificity of 99.8% and sensititity of 95.1%. Of note clinical sensitivity defined as detection of positive cases with an oropharyngeal-swab derived Ct value < 33, was 100%. Comparative analysis of Ct values derived from saliva vs. oropharyngeal swabs demonstrated a significant difference (mean difference 4.23 (95% CI 2.48 to 6.00). Conclusions The Salivette system is an easy-to-use, safe and feasible collection method for saliva sampling and subsequent SARS-CoV-2 testing in children aged 3 years and above. In view of the excellent sensitivity and specificity documented in our study, this novel testing approach is a very reliable and much more pleasant alternative to oropharyngeal swab based testing, particularly in children and for self-testing in the home setting.