Coronavirus in our sewage system

We know that coronavirus is spread via air droplets, but it is also clearly capable of spreading to our sewage systems through faecal matter.

While this is undoubtedly worrying news, it’s also highly interesting from an epidemiological point of view. Since the beginning of lockdown, the health authorities have been concentrating on testing to track the epidemic and prepare for a potential second wave, but these tests have so far been conducted only in symptomatic people, at least in France.

The virus concentrations detected in sewage could thus offer valuable information about the current stage of the epidemic. This is the hypothesis put forward by a group of researchers from Eau de Paris, the organisation in charge of all Greater Paris waterworks, as they analysed the sewage of Ile de France using PCR tests over several weeks.

As early as March 5, the results they obtained revealed that traces of the virus were already detected in the sewage, despite less than 100 cases having so far been confirmed. They then found that these concentrations constantly increased up until one week after lockdown before progressively falling. Laurent Moulin, a microbiologist at Eau de Paris, sees these findings as a highly sensitive indicator that could enable future predictions of a second wave, should one happen.

1) https://www.medrxiv.org/content/10.1101/2020.04.12.20062679v2