Photo: Getty Images

Declining coronavirus level in wastewater


The concentration of coronavirus in the wastewater of Gothenburg has returned to a relatively low level, the latest findings and analyses from the University of Gothenburg show.

Heléne Norder, Institute of biomedicine, Sahlgrenska Academy at the University of Gothenburg.
Photo: Elin Lindström

“Fortunately, this is reassuring news. The level of SARS-CoV-2 in the wastewater is now on the way down again,” says research leader and microbiologist Heléne Norder about the current weekly result.

From July 1st, the concentration of SARS-CoV-2 in the Gothenburg wastewater was initially low. It then rose, within a couple of weeks, to a level exceeding the early peaks during the pandemic. It has now fallen once more.

The latest weekly measurement is based on samples taken in the week of July 25th–31st.

Measure of infection status

These surveys of SARS-CoV-2 in the city’s wastewater have been underway since February 2020. They are performed by a group of researchers at Sahlgrenska Academy, University of Gothenburg, in collaboration with Gryaab, the municipally owned enterprise that treats wastewater in Gothenburg and surrounding municipalities.

Every week, Gryaab assists the scientists by providing a sample containing a collection of daily samples of the wastewater. The group, which then measures and analyzes the samples, reports directly to the Infection Control Unit and care providers in Västra Götaland County.

Coronavirus in wastewater indicates the scale of virus infections in the community. However, the association between viruses in the wastewater and the proportion of seriously sick people has successively declined with the growing strength of protection from vaccination.

Enteroviruses and adenoviruses

Besides SARS-Cov-2, the enterovirus level is investigated. This has fallen significantly, the latest weekly measurement shows. Enteroviruses can cause a wide range of symptoms from the common cold to pericarditis (inflammation of the pericardium, the fluid-filled sac surrounding the heart), meningitis and paralysis. For the majority, however, the symptoms are mild.

The current weekly measurement of wastewater in Gothenburg shows that concentrations of adenoviruses, which cause respiratory infections and are suspected of also causing jaundice in children, have risen slightly.