Coronavirus concentration in wastewater has decreased to a moderate level in many regions of Estonia, the University of Tartu's latest wastewater monitoring study shows. The number of samples with very high a concentration has dropped by a third in a week.
The leader of the study, University of Tartu Professor of Technology of Antimicrobial Compounds Tanel Tenson said although the amount of the virus has decreased in most places, the readings in the larger cities of Ida-Viru County still remain high.
The concentration is also high in Tallinn and the Viimsi-Muuga area, Haapsalu, Pärnu, Tartu and in Võru County. According to Tenson, the current indicator is still comparable to the one at the beginning of February.
"Considering that currently, the level of new infections is relatively high, it still takes time before we can see a bigger change," Tenson explained.
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 helps 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.
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".
Editor: Helen Wright