Fraunhofer Institute for Industrial Mathematics ITWMA team from our division »Optimization« and the department »Transport Processes« is investigating the incidence of infection in Rhineland-Palatinate based on wastewater analyses relating to coronavirus and the representative »SentiSurv« cohort study. Always in view: How can the results help us to be better prepared?
Anhand von Abwasser-Analysen zu Corona und der repräsentativen Kohortenstudie »SentiSurv« untersucht ein Team unseres Bereichs »Optimierung« und der Abteilung »Transportvorgänge« das Infektionsgeschehen in Rheinland-Pfalz. Immer im Blick: Wie können die Ergebnisse uns dabei helfen, besser vorbereitet zu sein?
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What Wastewater Tells Us About Infections
Monitoring Viral Loads in Wastewater: A Key to Early Infection Detection and Health Prevention
Wastewater is a rich source of information that was already being used occasionally to identify pathogens before the COVID-19 pandemic. However, wastewater monitoring has only been the subject of intensive research since the coronavirus years. Back in March 2021, the EU Commission called on the member states to introduce systematic monitoring of SARS-CoV-2 in wastewater under the project name »ESI-CorA«. In February 2022, a nationwide pilot operation for coronavirus wastewater monitoring was therefore launched at a total of 56 locations. The Rhineland-Palatinate Ministry of Science and Health has also included a total of 16 wastewater treatment plants that provide two samples per week.
Combining Wastewater Data with Cohort Study Results Yields Optimal Data Situation
»Germany initially lagged somewhat behind in European comparison, but Rhineland-Palatinate is now a pioneer in this type of study,« says Dr. Neele Leithäuser. Our researchers have also contributed to this, as they have repeatedly used their expertise to support state policymakers with figures and tools to make decisions on various issues. »In late summer 2022, it was clear that the mass tests would be phased out and that there would no longer be any reliable figures. Prevalence in particular is what you need to be able to assess the situation,« explains Dr. Jan Mohring.
This refers to the total number of cases of illness in the population under consideration. »But it was not possible to determine this on the basis of wastewater data alone. It was unclear: What do the wastewater values even mean? How many people are infected?« says the mathematician. The values are subject to many fluctuations and uncertainties – for example due to measurement inaccuracies or dilution.
»SentiSurv RLP« – Representative Cohort Study Supports Evaluation
It was a real stroke of luck that the project »SentiSurv« was launched at the same time as the new wastewater data on behalf of the Ministry. Under this name, the Mainz University Medical Center is monitoring the incidence of SARS-CoV-2 in the population of Rhineland-Palatinate. A representative population cohort took part in three phases from December 2022. Depending on the phase, this involved up to 12,000 people who tested themselves for coronavirus once or twice a week and passed on the results as a photo including a questionnaire via an app. The final phase took place from January to March 2024.
»In order to put the wastewater results in better perspective, it was particularly important that the locations of the wastewater treatment plants also have a large overlap with the »SentiSurv« cohorts. We were involved in the discussions with the state government and were able to put this forward as a proposal. This is certainly not something that happens very often anywhere in the world, such an optimal data situation that has brought us really great results,« says a delighted Neele Leithäuser. »To exaggerate a bit, we have found the magic conversion factor for prevalence, at least for this period, which nobody believed in at the beginning.« Researchers are learning from the »SentiSurv« and wastewater data. The detailed results are recorded, for example, in the paper »Estimating the COVID-19 Prevalence from Wastewater«. »However, we also know that the calibration can no longer take place if the cohort data is no longer available, then the wastewater data can be more off the mark again, especially with new variants, but we have the reference points,« summarizes Mohring.
It is crucial to derive the prevalence from data. It describes the total number of cases of illness in the population under consideration during a certain period of time.
Future Perspectives: Wastewater Monitoring as an Early Warning System
The aim of the study is to establish app-based monitoring to protect against future threats to public health, not just those caused by the pandemic. This can also facilitate the monitoring of other pathogens via wastewater. Elsewhere, new studies and projects are already underway to detect influenza, smallpox and polio pathogens.