Coronavirus concentration in waste water has increased again across Estonia

This week’s results of the wastewater analysis led by the University of Tartu show an increase in coronavirus levels. Samples with high virus concentration have been collected all over Estonia, which is why precautions to prevent the spread of the virus must be taken very seriously everywhere.

According to the lead researcher, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson, it is alarming that the slow decrease in the virus concentration in April has turned to rise again. “The increase is confirmed by the index illustrating of the average situation in Estonia, the samples collected from larger settlements, describing the average daily situation, as well as the point samples collected all over Estonia,” Tenson explained.

There has been some decline in western Estonia, though. At the same time, indicators of Harju County as well as southern and central Estonia have increased. Coronavirus levels in samples from Ida-Viru County have doubled compared to last week. According to Tenson, the current virus concentration in waste water is again comparable to that of the end of March. “Unfortunately, this may also be reflected in the rise in the number of the infected in the coming weeks,” said Tenson.

How and where are the samples collected?

Wastewater samples are collected at the beginning of every week in all county centres, cities with more than 10,000 inhabitants and, if necessary, in smaller settlements. Samples taken from larger cities reflect the situation of wastewater passing through the treatment plant over 24 hours, giving a reliable overview of the infection level in the city. In smaller places, spot samples are taken, showing the virus level in wastewater at the moment of sampling. Spot samples are more easily affected by various factors and should therefore be used over several weeks to estimate the trend, rather than get a definitive picture of the current situation.

The study is a tool helping the Health Board monitor changes in the outbreak dynamics and discover hidden outbreaks. It gives early information for estimating the spread of the virus before clinical cases are detected. The Health Board is regularly informed of the results.
In collecting the samples, the University of Tartu cooperates with the Estonian Environmental Research Centre and water companies operating the waste water treatment plants of Estonian cities. The 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,