During the week 8 to 14 November 2021, there were increasing or stabilizing trends, compared to the week 1 to 7 November 2021, in the average weekly viral load of SARS-CoV-2 in the urban wastewater of eight of the twelve regions (8/12) which were checked by the National Network of Sewage Epidemiology (EDEL) of EODY. A net increase in the average weekly viral load was observed in Patras (+ 96%), while the increases were marginal in Alexandroupolis (+ 18%), Agios Nikolaos (+ 27%) and Thessaloniki (+ 30%). The viral load remained stable in Volos (-9%), Xanthi (+ 3%), Attica Region (+ 5%) and Larissa (+ 9%).
Net reductions in the average weekly viral load of urban wastewater were observed in Ioannina (-54%) and Heraklion (-72%), while the reduction was observed in Chania (-18%). The viral load in the urban wastewater of the city of Corfu was detectable. It is noted that the change in the weekly average of viral load compared to the previous week can not be assessed, as only two samples were taken.
In the week of November 8-14, no samples were tested from Rethymno.
The samples are taken from the entrances of the local Wastewater Treatment Plants (WWUs) and correspond to the population served by them.
Region of Attica: In the last week, 08-14 / 11/21, the average weekly viral load in the urban wastewater of the Attica Region showed a stabilizing trend, with a statistically insignificant change (+ 5%) of the weekly average compared to the previous week, 01- 07/11/21. The upward trend in the viral load of wastewater in the Attica Region started in mid-September 2021 and since then the viral load has been gradually increasing. The largest increase was observed in the last two weeks of October and the first week of November, while in the last week (08-14 / 11/21) and the second week of November the viral load of sewage showed a stabilizing trend.
Thessaloniki: In the last week, 08-14 / 11/21, in Thessaloniki, the weekly average value of the viral load of urban wastewater showed an increase (+ 30%) compared to the previous week, 01-07 / 11/21. This increase, although marginal, is considered significant because viral load values ​​are high. The average weekly price of viral load from mid-September to date has increased by 770%. However, in the last week, for the first time after a month of continuous growth, there has been a decline in the rate of increase in viral load.
Larissa: In the last week, 08-14 / 11/21, the average weekly viral load of urban wastewater in Larissa remained virtually stable (+ 9%) compared to the week 01-07 / 11/21. Viral load levels remain particularly high. The upward trend in the viral load of sewage in the city of Larissa started in mid-September 2021 (week 13-19 September). Overall, the weekly average value of the viral load from mid-September to date has increased eightfold.
Marble: In the last week, 08-14 / 11/21, the average weekly viral load of urban wastewater in Volos remained virtually stable (-9%) compared to the week 25-31 / 10/21. Viral load levels remain particularly high. The upward trend in the viral load of sewage in the city of Volos started in mid-September 2021 (week 13-19 September). Overall, the weekly average value of the viral load from mid-September to date has increased elevenfold.
Heraklion: In the last week, 08-14 / 11/21, in the city of Heraklion, the weekly average value of the viral load of urban wastewater showed a decrease (-72%) compared to the previous week, 01-07 / 11/21.
Chania: In the last week, 08-14 / 11/21, in the city of Chania, the weekly average value of the viral load of urban wastewater showed a marginal decrease (-18%) compared to the previous week, 01-07 / 11/21.
Saint Nicholas: In the last week, 08-14 / 11/21, in the city of Agios Nikolaos, the weekly average value of the viral load of urban wastewater showed a marginal increase (+ 27%) compared to the last week, 01-07 / 11/21 .
Patras: In the last week, 08-14 / 11/21, in Patras, the average weekly viral load of urban wastewater showed a significant increase (+ 96%) compared to the previous week, 01-07 / 11/21.
Blonde: In the last week, 08-14 / 11/21, the average weekly viral load of urban wastewater in Xanthi remained stable (+ 3%) compared to the week 01-07 / 11/21. Viral load levels remain particularly high. The upward trend in the viral load of sewage in the city of Xanthi started in mid-September 2021 (week 13-19 September). Overall, the average weekly viral load has tripled since mid-September.
Alexandroupolis: In the last week, 08-14 / 11/21, in Alexandroupolis, there was a marginal increase (+ 18%) in the average weekly viral load of urban wastewater compared to the week 01-07 / 11/21. Viral load levels remain particularly high. The upward trend in the viral load of the wastewater of the city of Alexandroupolis started from mid-September 2021 (week 13-19 September). Overall, the weekly average value of the viral load from mid-September to date has increased by 3.5 – 4 times.
Janina: In the last week, 08-14 / 11/21, in Ioannina, the average weekly viral load of urban wastewater showed a decrease (-54%) compared to the previous week, 01-07 / 11/21.
Corfu: Last week, 08-14 / 11/21, in the city of Corfu, a viral load was detected in the urban wastewater of the city. The change in the weekly average of the viral load in relation to the previous week, 01-07 / 11/21, cannot be evaluated, as only two samples were taken.
The laboratories that participate in the network are: Laboratory of Analytical Chemistry of the National and Kapodistrian University of Athens, Interdisciplinary Laboratory Team of Sewage Epidemiology of the Aristotle University of Thessaloniki, Regional Laboratory of Public Health of Thessaly Of Hygiene and Epidemiology of the Department of Medicine of the University of Ioannina.
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