Coronavirus concentration in waste water is decreasing slowly but noticeably

This week's results of the waste water analysis led by the University of Tartu indicate that the concentration of coronavirus in waste water is slowly decreasing. The situation is finally starting to improve also in Põlva County, which has stood out with the highest infection rates in the current wave.

A few new places with very high virus levels have been added to this week's map, but the number of places with a wide spread of the virus, marked by orange, has dropped considerably. There are several new smaller places where no virus was found this time, though these were spot samples reflecting the situation at the moment of sampling.

According to the lead researcher of the study, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson, the virus is still very widely spread across Estonia, but the decline in virus levels is noticeable. "There is no major decline yet, but the situation is improving. I am happy to see that the virus levels in Põlva and Põlva County have finally started to recede. This gives us some hope that soon the burden of hospitals in southern Estonia will be eased," said Tenson. Samples from the Jõhvi-Ahtme region as well as Tartu, Rapla and Viljandi still show very high levels of the virus.

How are the samples collected?

Waste water 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 waste water passing through the treatment plant over 24 hours, giving a reliable overview of the infection level in the city. The spot samples taken in smaller places show the situation at the moment of sampling. Spot samples are more easily affected by various factors and should therefore be used in comparison 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 the collection of samples, the University of Tartu cooperates with the Estonian Environmental Research Centre and water companies operating the water treatment plants of Estonian cities. The samples are analysed at the laboratories of the University of Tartu Institute of Technology.

For more information about the previous results of the study, see the home page of the study "Detecting coronavirus in waste water”.

The waste water study is funded by the European Regional Development Fund from the EU measure to respond to the Covid-19 pandemic.

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