Education and Science, Estonia

Director General of the Health Board Ullar Lanno said that this monitoring method enables to discover undetected virus spread a week earlier and prompt the Health Board to monitor the spread by testing when the corresponding signal emerges.

"In today's epidemiological situation where we have noted a decrease in the share of outbreak-based spread, there is a risk that we won't be able detect a persistent country-wide spread in a timely manner. The results of waste water analysis will help us get a better overview of the situation," Lanno said, adding that according to current experience, a signal indicating the presence of the coronavirus in waste water emerges five to seven days before the infectious patient sees a doctor. 

"With reference to Rapla, waste water analyses showed that there were virus carriers in the area. As we later saw, this was indeed the case," he said.

In addition to predicting outbreaks and rendering regional testing more efficient, waste water monitoring also enables to confirm the end of outbreaks.

"The signal disappearing from waste water, in turn, helps us determine if the spread of the virus has ended in the region," Lanno noted.

This was the case with the outbreak that emerged at Tartu nightclubs at the end of July and, based on waste water analyses, abated in the second half of August without spreading more broadly in South Estonia. For that reason, it was decided that spectators would be allowed to attend Rally Estonia.

The Health Board has been using the results of waste water analyses from August this year. Head of the study and professor in the technology of antimicrobial compounds at the University of Tartu's Faculty of Science and Technology Tanel Tenson said that samples are collected in Estonia's rural municipality centers and larger towns and cities.

Samples are also taken at random and as needed in smaller urban communities and near objects of local importance.

"The emergence of the virus in such samples is indicative of possible new outbreaks. As part of out study, we've found a method enabling to detect traces of the virus in waste water before clinical patients are found, thus providing the Health Board with an additional tool for the early detection of virus outbreaks," Tenson said.

The monitoring study is carried out by the University of Tartu in cooperation with the Health Board and the Estonian Environmental Research Center, and financed by the Ministry of Education and Research. Waste water analysis has previously been used for finding drugs, pharmaceutical residues and various types of viruses.