Wastewater biomarker CoV2: wastewater epidemiology using the example of a SARS-CoV-2 biomarker for the estimation of COVID-19 infections on the population scale

Wastewater-based epidemiology (WBE) is gaining popularity as a diagnostic method to estimate drug and medication use for entire sewersheds. SARS-CoV-2 can also be used as a biomarker in the context of wastewater diagnostics, on the one hand to detect a change in the infection pattern at an early stage and on the other hand to better elucidate the number of unreported COVID-19 cases at the population scale. For this purpose, the amount of virus in wastewater must be reliably analyzed and detected. The detection of SARS-CoV-2 is based on different PCR analyses with previously prepared wastewater samples (see work flow in Figure 1). In this regard, there is a need for research to harmonize methods for enveloped viruses such as SARS-CoV-2, on the optimization of the treatment procedures for the detection of the amount of virus in raw wastewater, and on the active integration into the corona infection management of the health authorities.

For the correct estimates of virus concentration in the wastewater, it is also very important to consider other factors, such as population density, the size and coverage of the sewer system, the volume of wastewater generated, degree of extraneous water, and substance-specific variables such as excretion rates, as well as the fate and transport of SARS-CoV-2 in the sewer network. To reduce the uncertainty of the wastewater based monitoring, these factors must be considered when estimating the incidence of infection. The results from this project can be used to develop a novel SARS-CoV-2 biomarker concept that will serve as an early warning system and can also be used to estimate the spread of infection directly by authorities. Such a concept may be extended to an estimation of the incidence of infection by other viruses or its early detection or tracking.

The key objectives of this project are:

- the development of methods for the quantitative determination of SARS-CoV-2 biomarkers, including mutants and viral surrogates, from raw wastewater

- the development and testing of strategies to identify local infection hot spots in a community

- the accurate estimation and prediction of COVID-19 infections in a community based on the presence of enveloped viruses in municipal wastewater; and

- The transferability of the developed methodology and biomarker model to other pathogenic viruses.

To achieve these goals, numerous cities and municipalities in Southern Germany with which we have already gained initial experience in mid-2020 were sampled regularly since October 2020. The map in Figure 2 shows the participating sites. In particular, high-resolution monitoring has been taking place at 5 locations in the county of Berchtesgadener Land in Southeast Germany since October 2020. Here, the recorded virus concentrations in wastewater are correlated with the community-specific case numbers and communicated to the crisis management team within 48 hours. Meanwhile, a ArcGIS-based dashboard has been developed for faster data sharing and better networking. This concept enables fast information management, short decision-making paths and is so far unique in Germany.