Results of WICOVIR Gargle Pool PCR Testing in German Schools Based on the First 100,000 Tests

Abstract

Background: Opening schools and keeping children safe from SARS-CoV-2 infections at the same time is urgently needed to protect children from direct and indirect consequences of the COVID-19 pandemic. To achieve this goal, a safe, efficient, and cost-effective SARS-CoV-2 testing system for schools in addition to standard hygiene measures is necessary.Methods: We implemented the screening WICOVIR concept for schools in the southeast of Germany, which is based on gargling at home, pooling of samples in schools, and assessment of SARS-CoV-2 by pool rRT-PCR, performed decentralized in numerous participating laboratories. Depooling was performed if pools were positive, and results were transmitted with software specifically developed for the project within a day. Here, we report the results after the first 13 weeks in the project.Findings: We developed and implemented the proof-of-concept test system within a pilot phase of 7 weeks based on almost 17,000 participants. After 6 weeks in the main phase of the project, we performed >100,000 tests in total, analyzed in 7,896 pools, identifying 19 cases in >100 participating schools. On average, positive children showed an individual CT value of 31 when identified in the pools. Up to 30 samples were pooled (mean 13) in general, based on school classes and attached school staff. All three participating laboratories detected positive samples reliably with their previously established rRT-PCR standard protocols. When self-administered antigen tests were performed concomitantly in positive cases, only one of these eight tests was positive, and when antigen tests performed after positive pool rRT-PCR results were already known were included, 3 out of 11 truly positive tests were also identified by antigen testing. After 3 weeks of repetitive WICOVIR testing twice weekly, the detection rate of positive children in that cohort decreased significantly from 0.042 to 0.012 (p = 0.008).Interpretation: Repeated gargle pool rRT-PCR testing can be implemented quickly in schools. It is an effective, valid, and well-received test system for schools, superior to antigen tests in sensitivity, acceptance, and costs.

How to Implement Safe, Efficient and Cost-Effective SARS-CoV-2 Testing in Urban and Rural Schools within One Month

“…We addressed all general issues extensively in our previous publication, and we showed that these did not depend on the region where the test system was implemented [10]. We demonstrated that the test system is safe, as it protected participating schools from outbreaks; efficient, as it successfully led to the identification of a positive individual within a day; and cost-effective, as it reduced the costs per tested participant to less than €1 in the study setting.…”

“…The overall technical feasibility of gargle-based pool testing in a pandemic has been shown repeatedly [10]. In a previous feasibility study, we established that implementing an algorithm that required participating families to remember to access a web-based app on a regular basis, to enable selection of participants for each testing round, based on an algorithm to maximize the probability of detecting a positive case, was a rate-limiting step [7].…”

“…In a previous feasibility study, we established that implementing an algorithm that required participating families to remember to access a web-based app on a regular basis, to enable selection of participants for each testing round, based on an algorithm to maximize the probability of detecting a positive case, was a rate-limiting step [7]. The inclusion of all pupils attending the participating schools in the WICOVIR program, made possible by the reduction in testing costs, enabled implementation of a successful monitoring program, in which chains of infection were broken before the emergence of symptoms [10]. The question remained, however, whether such an approach could be implemented outside of a clearly defined study setting, such as on a university campus or within a small test area, and, if applicable, which resources and set-ups would be necessary for a rapid implementation.…”

“…The WICOVIR project was designed in January 2021, approved by the ethics committee of the University of Regensburg in March 2021 (file number 21-2240_2-101), proposed to the Bavarian State Ministry of Health in February, and funded at the end of March 2021. All study procedures and protocols are available online (www.we-care.de/wicovir) and have been published in detail elsewhere [10]. Here we present findings following the implementation of the test system in four different Bavarian counties (Figure 1).…”

“…We and others have shown that gargle-based pool Polymerase Chain Reaction (PCR testing can provide a safe, efficient, and cost-effective alternative, [6][7][8][9] and thus the WICOVIR (Where Is the COrona VIRus?) study was initiated in March 2021 in the south of Germany [10].…”