The results of the laboratory tests of the National Network of Sewage Epidemiology for the epidemiological surveillance of the SARS-CoV-2 virus in urban wastewater, which operates under the coordination of EODY, were announced.

The samples come from the Attica Region and the cities of Thessaloniki, Larissa, Volos, Heraklion, Chania, Rethymno, Agios Nikolaos Lassithi, Patras, Xanthi, Alexandroupolis and Ioannina. The samples are taken from the entrances of the local Wastewater Treatment Plants (WTPs) and correspond to the population served by them.

Conclusions: During the week 18 to 24 October 2021, there were increasing changes, compared to the week 11 to 17 October 2021, in the average weekly load of SARS-CoV-2 in the urban wastewater of ten of the twelve (10/12) areas tested from the National Network of Sewage Epidemiology of EODY. The net growth trends ranged from + 33% in Thessaloniki to + 247% in Agios Nikolaos, while marginal increases in the average weekly load of urban wastewater were observed in the Attica Region (+ 11%) and in Volos (+ 14%). Marginal reductions in the average weekly load of urban wastewater were observed in Xanthi (-18%) and Ioannina (-27%).

Region of Attica: In the last week, 18-24 / 10/21, the average weekly load in the urban wastewater of the Attica Region showed a marginal increase, with a statistically insignificant change (+ 11%) of the weekly average, to the previous week, 11- 17/10/21.

Thessaloniki: In the last week, 18-24 / 10/21, in Thessaloniki, the weekly average value of the viral load of urban wastewater showed an increase (+ 33%) compared to the previous week, 11-17 / 10/21. In the last four weeks, the viral load in the city of Thessaloniki has shown a continuous increase, with the total increase amounting to + 145%.

Larissa: During the week, 18-24 / 10/21, the average weekly load of urban wastewater in Larissa showed the last increase (+ 60%) compared to the week 11-17 / 10/21.

Marble: In the last week, 18-24 / 10/21, the average weekly load of urban wastewater in Volos showed a marginal increase (+ 14%) compared to the week 11-17 / 10/21.

Heraklion: In the last week, 18-24 / 10/21, in Heraklion, the average weekly viral load in the urban wastewater of the city showed a significant increase (+ 109%) compared to the previous week, 11-17 / 10/21. This increase followed the gradual de-escalation of the viral load, which had been observed in the urban wastewater of the city of Heraklion, from the beginning of September 2021.

Chania: In the last week, 18-24 / 10/21, in Chania, the average weekly load of urban wastewater showed a significant increase (+ 200%) compared to the previous week, 11-17 / 10/21. This increase followed the continuous de-escalation of the viral load, which he had observed in the urban wastewater of the city of Chania, from the beginning of September 2021.

Rethimno: In the last week, 18-24 / 10/21, in Rethymno, the average weekly viral load of urban wastewater showed a significant increase (+ 118%) compared to the previous week, 11-17 / 10/21. This increase followed the continuous decrease of the viral load, which had been observed in the urban wastewater of the city of Rethymnon, from the end of August 2021.

Saint Nicholas: In the last week 18-24 / 10/21, in Agios Nikolaos, the average weekly viral load of urban wastewater showed a significant increase (+ 247%) compared to the previous week, 11-17 / 10/21. This increase followed the decrease that had been observed in the viral load of urban wastewater in the city of Agios Nikolaos since the beginning of September 2021.

Patras: In the last week, 18-24 / 10/21, in Patras, the average weekly load in the urban wastewater of the city showed a significant increase (+ 139%) compared to the previous week, 11-17 / 10/21.

Blonde: In the last week, 18-24 / 10/21, in Xanthi, the average weekly load of urban wastewater showed a marginal decrease (-18%) compared to the week 11-17 / 10/21.

Alexandroupoli: In the last week, 18-24 / 10/21, in Alexandroupolis, there was an increase (+ 35%) in the average weekly load of urban wastewater compared to the week 11-17 / 10/21.

Janina: In the last week, 18-24 / 10/21, in Ioannina, the average weekly load of urban wastewater showed a marginal decrease (-27%) compared to the previous week, 11-17 / 10/21.