A sign that should alert.
The concentrations of the SARS-Co-2 coronavirus found in wastewater in the Paris region increased slightly this week, according to samples taken as part of the Obépine network.
The last time such an observation was made was in early June, at the start of the second wave.
But we were starting from much lower levels than today.
This epidemiological observatory in wastewater was set up in early March 2020 at the initiative of Sorbonne University and the operator Eau de Paris.
Two new series of analyzes have taken place in recent days in the five Ile-de-France stations connected to the network.
And the results sound like a red flag.
"This is, since the end of October, the first time that we have observed a real increase in traces of viruses in wastewater," said the Parisian Vincent Maréchal, virologist at Sorbonne University.
Equivalent levels mid-September
The latest curves sent to us by the Obépine team show a slight increase in the average virus concentrations at the level of the various stations in the Ile-de-France region, after more than a month and a half of decline (in reality, the curve rises slightly from the end of December because the data has been smoothed).
The levels now reached join those of mid-September, a month and a half before the peak of the second wave.
In Marseille, the marine firefighters (who do not work within the framework of the Opébine network) also indicated this Thursday to have observed "a stronger circulation of the virus in the waste water" Monday and Tuesday.
The first signs of a stronger circulation of the virus in wastewater have appeared two days ago and more particularly in certain areas where ALL TOGETHER we must strengthen the gest 🙌 barriers.
@sup_recherche @marseille @MarinsPompiers pic.twitter.com/fbdqDRY7QN
- Marins-Pompiers de Marseille (@MarinsPompiers) January 7, 2021
However, as we could see at the beginning of the summer and then of the autumn, the evolution of the curve generally makes it possible to anticipate by a few days that of the new positive cases, on the rise as on the fall.
Indeed, when a person is infected, the virus “also integrates the digestive system and we find viral genome in large quantities in the stool”, told us at the end of November Laurent Moulins, head of the research and development laboratory at Eau de Paris. .
This is how it is found in wastewater.
"Our model is refined and I think it is taken more and more seriously", rejoices Laurent Moulins.
"In view of the first results, the analysis of wastewater appears to be a complementary macro-epidemiological tool to other indicators and its mathematical modeling could allow very early detection", also estimated the Ministry of Higher Education and Research in a press release published on November 17.
Public health France "expects an increase in the spread of the virus"
The increase in virus concentrations observed this week in wastewater in Île-de-France therefore raises fears, in the coming days, of a stronger rise in the number of cases.
In less than two weeks, we have already gone from 2,000 to nearly 2,500 positive people per day on average in the region, in particular due to massive screening before the holidays (which also explains why the curve has risen quite early) .
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However, these worrying data remain to be confirmed.
During the holidays, the mixing of populations may have slightly distorted the analyzes, for example.
"We will have to wait until next week to find out whether we are truly part of a more active resumption of the circulation of the virus, or if it is a more cyclical phenomenon", himself recognizes Vincent Maréchal, specifying that these data "were transmitted in real time to the regional health agencies".
Visiting @LCPME_CNRS_UL of the #OBEPINE network in Nancy, whose teams analyze wastewater to detect the presence of viral loads, such as those from # SARS_CoV_2.
A decisive scientific project in the service of the fight against # COVID19.
#TerritoiresdeSavoirs pic.twitter.com/Ysyg46u1zT
- Frédérique Vidal (@VidalFrederique) October 2, 2020
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Public health France is already leaning towards the first hypothesis.
In the coming days, "we expect an increase in the spread of the virus" and "it is likely that we will see an increase in hospitalizations," said one of its epidemiologists, Christine Campese, on Friday. from a remote press point.
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