Coronavirus amounts in waste water are increasing everywhere in Estonia

This week’s results of the waste water study led by the University of Tartu show the continued spread of the coronavirus. The virus is most prevalent in Ida-Viru county and southern Estonia. Compared to earlier weeks, the virus concentration in waste water has also grown in western Estonia.

Last week, the researchers noted the biggest increase in the virus amount in samples collected from Harju county, Ida-Viru county and southern Estonia. This week, the situation has slightly improved in these places, but in Ida-Viru county and southern Estonia, the virus content is much higher than the index representing the average in Estonia. There, the biggest increase in the number of infections can be predicted in the upcoming weeks, according to the lead researcher of the study, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson.

“This week, we can see that coronavirus is found in predominantly large quantities throughout Estonia. Even the smaller settlements have not remained intact. The virus has now also reached the island of Hiiumaa, which remained virus-free for a long time,” said Tenson. “In the current wave of coronavirus, we have seen a constant growth in virus amounts since mid-August. There haven’t been any major upsurges, but the figures have crept up quite close to the level we had in February, when both the number of infections and the virus amounts approached their peak," he explained.

How and where are the samples collected?

Waste water samples are collected at the beginning of every week in all Estonian 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. In smaller places, spot samples are taken, showing the virus level in waste water 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 to estimate 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 about 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, tanel.tenson@ut.ee