National-scale surveillance of emerging SARS-CoV-2 variants in wastewater

SARS-CoV-2 surveillance is crucial to identify variants with altered epidemiological properties. Wastewater-based epidemiology (WBE) provides an unbiased and complementary approach to sequencing individual cases. Yet, national WBE surveillance programs have not been widely implemented and data analyses remain challenging.

We deep-sequenced 2,093 wastewater samples representing 95 municipal catchments, covering >57% of Austria’s population, from December 2020 to September 2021. Our <underline>Va</underline> riant <underline>Qu</underline> antification in S <underline>e</underline> wage pipeline designed for <underline>Ro</underline> bustness ( VaQuERo ) enabled us to deduce variant abundance from complex wastewater samples and delineate the spatiotemporal dynamics of the dominant Alpha and Delta variants as well as regional clusters of other variants of concern. These results were cross validated by epidemiological records of >130,000 individual cases. Finally, we provide a framework to predict emerging variants de novo and infer variant-specific reproduction numbers from wastewater.

This study demonstrates the power of national-scale WBE to support public health and promises particular value for countries without dense individual monitoring.

Graphical Abstract

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