Laboratory tests conducted on urban wastewater by the National Network of Sewage Epidemiology show a significant increase in the average viral load in all 12 cities inspected from December 27 to January 2 over the previous week.
The samples collected showed a massive jump of 516% in Aghios Nikolaos in Crete, 342% in Larissa, 290% in Ioannina and 283% in Corfu.
Thessaloniki, Alexandroupoli and Volos also saw three-figure increases, of 177%, 158% and 140%, respectively.
In Attica, which includes the capital, Athens, the increase was 95%.
Increases were also found in Xanthi 50%, Patras (45% ), Hania (38%) and Iraklio (26%).
Wastewater analysis is believed to give an early warning for upcoming epidemiological trends.