Waste water study confirms even spread of coronavirus throughout Estonia

TALLINN – This week’s results of the waste water monitoring study led by the University of Tartu show that coronavirus has spread evenly all over Estonia.

In southern Estonia, the virus amounts have somewhat decreased, while in central Estonia, the number of settlements with high virus concentration has grown. The island of Hiiumaa remains free of the coronavirus.

Tanel Tenson, the lead researcher of the study and professor of technology of antimicrobial compounds at the University of Tartu, said he appreciates the fact that the recent weeks have not shown a marked increase in virus amounts. In southern Estonia, the coronavirus level is still slightly higher than the index describing the average situation in Estonia, but the situation has somewhat improved compared to last weeks. At the same time, the virus concentration has grown in several settlements of central Estonia and in Parnu County. "The results suggest that in the coming weeks, the increase in new infection cases will be quite similar to the current situation," Tenson said.

Waste water samples are collected at the beginning of every week in all Estonian county centers, 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 Center and water companies operating the waste water treatment plants of Estonian cities. The samples are analyzed at the laboratories of the Institute of Technology of the University of Tartu.