The Swedish Environmental Epidemiology Center (SEEC), part of the SciLifeLab Pandemic Laboratory Preparedness initiative, continuously performs analysis of Swedish wastewater to monitor the spread of COVID-19 across Sweden. Their latest results show that the level of SARS-CoV2 in wastewater has risen drastically in a short period and that Omicron had completely outcompeted Delta in early January 2022.
The prevalence of SARS-CoV2 in wastewater is now increasing in all places investigated by the SEEC, a newly established center with researchers from SLU, KTH, KI and Uppsala University. SEEC monitors wastewater in for example Stockholm, Malmö, Uppsala, Örebro, Umeå, Kalmar, Enköping and Knivsta.
“We can see that the wastewater samples reflect the development of the spread of infection in society, and in times when the test capacity is not sufficient, these measurements can be of great importance for responsible authorities”, says Anna Székely (SLU), who is in charge of the project, in a press release from SLU.
During week 50 to week 2, samples from Umeå, Uppsala, Örebro and Kalmar, were analyzed to specifically monitor the presence of the Omicron variant. The data showed that Omicron very quickly has outcompeted the previous variant of concern (VOC) Delta, in only two weeks, with 0 percent in week 51 to 100 percent in week 1, Umeå and week 2, Uppsala and Örebro. Only in Kalmar, small amounts of Delta could still be detected during week 2.
“It is fascinating to see how quickly Omicron has totally taken over the stage”, Maja Malmberg (SLU).
“There is still a lot that we need learn about how the secretion of virus in feces is affected by for example virus variants, vaccination status or if you suffer from a mild or serious illness, but despite this, measurements seem to be reliable enough to be able to detect new outbreaks”, says Maja Malmberg.
The results for SARS-CoV2 in wastewater are published every week on the Swedish COVID-19 data portal. Samples are collected on Mondays and results are published on Fridays or Saturdays the same week. The researchers are also supported by grants from the Knut and Alice Wallenberg Foundation, via the SciLifeLab National COVID-19 Research Program.
Photo: Kari Kohvakka, Stockholm Vatten