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Coronavirus level in wastewater still low


The wastewater concentration of coronavirus in Gothenburg is still relatively low, the University’s latest measurements and analyses show.

Last week, a sharp fall in the level of SARS-CoV-2 in the wastewater in Gothenburg was reported. The results showed that a 16-week period of corona levels at or above the peaks of previous pandemic waves was over.

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

The current weekly measurement is based on samples taken in the week of April 18-24, and the results show a further decline, albeit very small. Heléne Norder, microbiologist and head of the research group, can thus note the lowest level since the sampling taken week of December 13-19 last year.

– The amount of virus is still at a relatively low level, much like last week. Hope it stays or sinks more, she says.

More than two years of investigations

These investigations of SARS-CoV-2 levels in the Gothenburg wastewater have been underway since February 2020. They are performed by a research group at Sahlgrenska Academy, University of Gothenburg, assisted by Gryaab, the municipally owned company that treats wastewater in Gothenburg and surrounding municipalities.

Every week, Gryaab supplies the scientists with a sample composed of daily wastewater samples. After measuring and analyzing the weekly samples, the group reports directly to the Infection Control Unit and care providers in Västra Götaland.

The amount of coronavirus in wastewater indicates the prevalence of the virus and associated disease (COVID-19) in the community. The connection between the virus level in the wastewater and the proportion of people who are severely ill has, however, weakened successively with the strengthening of protection afforded by vaccinations.

Levels for other viruses

Besides SARS-CoV-2, the concentration of norovirus GG2 (the “winter vomiting bug”) is also measured. According to the latest results, its level has now fallen for the fifth consecutive week, and this trend is in line with normal seasonal variation.

The concentration of enterovirus is fluctuating at a continued relatively high level. Enterovirus can cause a broad range of symptoms from the common cold to inflammation of the pericardium (the fluid-filled, two-layered sac surrounding the heart), meningitis and paralysis, although most people infected get only mild symptoms.