Omicron strain detected in waste water in various places over Estonia

This week’s results of the waste water monitoring study led by the University of Tartu show that the overall coronavirus concentrations are fairly stable. However, the initial analysis of virus strains in waste water detected the Omicron variant in several places in Estonia.

Over the week, the number of settlements with moderate virus levels has decreased and there have been slightly more samples with very high virus content. According to the lead researcher of the study, Professor of Technology of Antimicrobial Compounds of the University of Tartu Tanel Tenson, the index describing the average situation in Estonia shows a stable overall situation. No regions are completely free from the virus yet. Over the week, the virus amounts have slightly increased in Harju County and in central Estonia. The situation in south Estonia remains stable.

An analysis of the virus strains in waste water samples showed the presence of small quantities of the Omicron variant in several settlements. “As this research method is still in development, all we can say now is that the new virus strain has emerged in different parts of Estonia. Next week's analyses will allow us to assess the accuracy of these measurements and the rate of spread of the new strain,” Tenson 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. 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 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”.

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, University of Tartu, 5344 5202,