Comment by mschuster91

> BTW, did you knew municipalities can easily measure fluctuations in drug usage by testing the sewage water?

Yep. Not just drugs are monitored this way, but also the spread of infectious diseases. That can lead to sometimes pretty weird findings - for example, polio virus is supposed to be extinct, but every so often it shows up in sewage monitoring of major German cities [1]. The cause most likely are people (tourists and immigrants) from Africa and Asia that got an attenuated virus-based vaccination in their home country shortly before they came here.

Covid is, at least in Bavaria, also part of the regular monitoring schedule [2], Austria monitors for Covid, RSV and influenza [3].

[1] https://www.aerzteblatt.de/news/erreger-der-kinderlaehmung-i...

[2] https://bay-voc.lgl.bayern.de/abwassermonitoring

[3] https://abwasser.ages.at/de/