ABSTRACT
In this report, we describe a national-scale monitoring of the SARS-COV-2 (SC-2) variant dynamics in Israel, using multiple-time sampling of twelve wastewater treatment plants. We used a combination of inclusive and selective quantitative PCR assays that specifically identify variants A19 or B.1.1.7 and tested each sample for the presence and relative viral RNA load of each variant. We show that between December-2020 and March-2021, a complete shift in the SC-2 variant circulation was observed, where the B.1.1.7 replaced the A19 in all examined test points. We further show that the normalized viral load (NVL) values and the average new cases per week reached a peak in January 2021, and then decreased gradually in almost all test points, in parallel with the progression of the national vaccination campaign, during February-March 2021. This study demonstrates the importance of monitoring SC-2 variant dynamics on a national scale through wastewater sampling. It also provides a proof-of-concept methodology for continuous surveillance by using a combination of inclusive and selective PCR tests, which is far more amendable for high throughput monitoring compared with sequencing. This approach may be useful for real-time dynamics surveillance of current and future variants, such as the Omicron (BA.1) variant. SynopsisThis study describes the continuous monitoring of the SARS CoV-2 variant B.1.1.7 circulation in wastewater in Israel using a positive/negative quantitative PCR assay.
