The Luxembourg Institute of Science and Technology (List) every week publishes an analysis of wastewater from across the country. The study forms part of the government’s monitoring of the pandemic, together with infection numbers and hospitalisations.
List screened water from 12 treatment plants across the grand duchy for the presence of Sars-CoV-2 and the results, like the previous two weeks, continue to show a higher national prevalence of the virus with the highest viral concentrations observed in the north of the country.
In latest report for the week of 16 August, the northern regions around Wiltz and Bleesbruck showed a more dominant increase compared to the other plants. The wastewater treatment plants in Pétange and, which will undergo €295m expansion works in 2023, also had high contamination levels earlier in the week.
Despite the significant decrease in the number of daily confirmed cases in the grand duchy using the data sourced from the , wastewater traces paint a different picture of the dominance of the virus among residents compared to the last quarter of 2020 when the number of confirmed cases tallied with the results from wastewater samples per 100,000 inhabitants.
Nevertheless, when compared to the final quarter of last year, traces of the virus have dropped significantly, and so has the daily infection rate.
Mismatch between the number of daily cases (grey bars) and traces of Sars-CoV-2 in wastewater (blue dots) Luxembourg Institute of Science and Technology (LIST)
List has specified that wastewater monitoring enables timely information on the evolution of the virus circulation throughout the country in 24 to 48 hours but its analysis is not intended to provide predictions.
Still, the government last autumn sent the country into a partial lockdown and introducing a curfew after a spike of virus particles was found in wastewater. Health minister Paulette Lenert (LSAP) at the time said that the real number of infections must be much higher than those detected through testing.
The process to analyse wastewater involves PCR tests similar to those used in the testing of people. An earlier analysis of wastewater showed the first residues of the virus in the grand duchy was detected.
Examining the presence of Sars-CoV-2 in wastewater was established on a weekly basis in the grand duchy at the end of March 2020.