“Overall, the situation is very relaxed,” said microbiologist Heribert Insam, head of the Microbial Resource Management working group at the University of Innsbruck, in an interview with the APA. However, there are still some hotspots in the Braunau district, in Linz Land, Wels Land or the city of Salzburg and its surroundings. Together with Norbert Kreuzinger from the Institute for Water Quality and Resource Management at the Technical University (TU) Vienna, Insam is co-founder of “Coron-A”, which has been examining wastewater samples from sewage treatment plants for SARS-CoV-2-RNA since April 2020, all the more independently of individual ones Corona tests to get an overview of the infection process. Compared to the last peak of the pandemic in April, fewer SARS-CoV-2 genetic residues are currently detected in wastewater by a power of ten. And: “The wastewater data currently does not indicate that the curve is going up as steeply as last year.”
Many questions unanswered
But that could change again, insam emphasizes, for example IF social life takes place more indoors again with the cooler weather. There are also question marks with regard to the measurement results: It is currently not entirely clear how the higher numbers of infections among younger people relate to the data, as these may excrete fewer or shorter viruses. The question of how infections of vaccinated people with likewise lower viral load in the wastewater are still to be clarified.
Early warning system for schools
As part of the “school location monitoring” research project that has just started by the Ministry of Education, the wastewater data are to be used as part of an early warning system for schools. Based on the data from 116 sewage treatment plants across the country – in combination with the current tests at all schools or 300 selected “guard” schools with PCR tests carried out – the infection situation in the schools is to be assessed. The catchment area of the sampled wastewater treatment plants covers three quarters of the schoolchildren and more than 3,000 school locations, whereby wastewater from educational institutions is not measured specifically, but the entire environment in the municipal wastewater treatment plants.
General trends not yet recognizable
According to Insam, the idea of Education Minister Heinz Faßmann (ÖVP) to prevent infections from entering the school by means of intensive testing at schools could have worked out. “That could have worked to a certain extent,” he says, referring to the data. General trends in relation to schools cannot be identified at the moment, however, this requires measurement results from several weeks.
The wastewater monitoring with a view to the schools is now to run over a year as part of a research project. The scientists want to model, for example, how dying wastewater data fit together with the incidence in schools. The idea is that you have a lead of three to four days over the individual tests. The program can show its real strength, however, when the infection rate decreases to such an extent that significantly fewer individual tests can be carried out.
Targeted regional measures
Then the infection process in society could be observed with little effort and at low cost via the wastewater screening and, if necessary, a regional measure could be implemented in a targeted manner. “We are not at this level yet, but it will come,” emphasized Insam. The prerequisite is that the infection process is sufficiently weakened by more and more vaccinated people. We are currently working with AGES to incorporate the wastewater data into forecasting tools for one to two weeks.