Several days before people show symptoms of COVID-19 infection, they excrete SARS-CoV-2 virus fragments in their stool, which can be detected in wastewater. By establishing an effluent-based early warning system, the trend of case numbers can be estimated. The emergence of new variants and their spread can also be detected earlier than is possible by testing individuals.

The pilot project "Systematic Surveillance of SARS-CoV-2 in Wastewater (ESI-CorA)" is funded by the European Commission under an Emergency Support Instrument. In the project, 20 pilot sites will be established in selected municipalities. During the pilot phase of one year, 2 samples will be taken weekly from the influent to the wastewater treatment plant over a period of 24 hours each. The samples are then processed in cooperating analytical laboratories and analysed using molecular biological methods (polymerase chain reaction, PCR). The results will be linked to health data on site and, if possible, will be incorporated into the assessment of the pandemic situation.