Record high concentration of coronavirus in waste water samples

This week’s results of the waste water analysis led by the University of Tartu reveal rapidly increased concentration of the coronavirus in waste water. According to the Health Board, an increase in infections after the restrictions were eased was to be expected, but the waste water analysis results call for vigilance.

According to the lead researcher, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson, this week’s figures are the highest in the history of the study. While just a week ago, the amount of samples with very high virus concentration was almost equal with that of samples of medium and low concentrations, now the virus concentration was high in 14 sampling sites of 20. “I can say that our samples have never before shown such a high virus level. The results allow us to deduce that the number of infections has increased a lot almost everywhere in Estonia,” Tenson explained.

The waste water monitoring study is a useful and helpful tool for the Health Board. Hanna Sepp, Head of the Department of Infectious Diseases Surveillance and Epidemic Control at the Health Board, said that the high virus readings in waste water samples all over the country are definitely alarming and call for vigilance, but other figures do not indicate a surge in infections. “The number of new COVID-19 cases has been very high in the recent weeks, but rather stable. There is also a persistently high level of positive tests indicating latent spread. Also the number of people in hospital care has remained on a stable level,” Sepp said. After the restrictions were eased, a rise in infections was expected, she added.

“Although the results of this study are not always consistent with the number of COVID-19 cases identified, the study proactively helps us focus our attention and actions, and build preparedness,” said Hanna Sepp.

From this week, uniform restrictions apply in Estonia to curb the spread of the coronavirus. Although restrictions were eased in some places, it still remains very important to observe the precautions everywhere. To protect us all, it is definitely necessary to stay home when unwell, avoid close contacts, wear face masks indoors and keep safe distance.

Waste water samples are collected every week in all Estonian county centres and cities with more than 10,000 inhabitants. Coronavirus monitoring in waste water gives early information for estimating the spread of the virus before clinical cases are detected. The monitoring helps to find hidden outbreaks and observe changes in the dynamics of outbreaks. In the collection of samples, the University of Tartu cooperates with the Estonian Environmental Research Centre and water companies operating the waste water treatment plants of Estonian cities. Waste water samples are analysed at the laboratories of the University of Tartu Institute of Technology.

For more information and the interactive map with the previous results of the study, see the home page of the study “Detecting coronavirus in waste water”.

Further information: Tanel Tenson, Professor of Technology of Antimicrobial Compounds, University of Tartu, 5344 5202,