Recently, the term “plateau” has replaced the notion of “epidemic peak”. It denotes a stagnation in the spread of the disease.
- At the start of the epidemic, we were waiting for the “peak”, that is to say the moment when the infection would affect the greatest number before regressing
- Today we speak of a “plateau” to say that the epidemic is progressing more slowly but not regressing.
When will we emerge from the Covid-19 epidemic? Only the scrupulous observation of the curves can make it possible to make forecasts, even if they are sometimes uncertain. At the start of the health crisis, the health authorities regularly used the notion of “epidemic peak”. It refers to reaching a peak of either cases or deaths, and suggests that once past, the situation should improve with a net decrease in numbers. Since then, the term “epidemic plateau” has replaced it, if it is reached, this means that the epidemic is stabilizing.
A stabilization rather than a decrease
“A very high plateau seems to be emerging, said the director general of health, Jérôme Salomon, on April 11, but the epidemic remains active.” This confirms the idea that an epidemic plateau is not necessarily synonymous with a drop in the number of cases, it may indicate a stagnation in the number of people infected and/or deceased from the virus. In Spain or Italy, there were plateau phases followed by a drop or rise in the number of deaths.
“Statistical noise” can pollute data
Some specialists call for caution when using the notion of “plateau”. At huff Post, Samuel Alizon, research director at the CNRS and specialists in epidemics, confides: “For the curve to be perfectly stable, each sick person would have to infect exactly one other. That does not seem realistic to me.” The data collected can be polluted by statistical noise, ie by delays or lack of precision in counting. Statistical variations can sometimes be linked to these shifts rather than to the effective slowing down of contamination.
The time is not for deconfinement
In France, in recent days, the balance of people in intensive care is negative: they were more likely to leave than to enter. Sunday April 12, it was for the 4th consecutive day. The effects of containment would be slowly appearing, it makes it possible to flatten the curve of the epidemic, that is to say that the number of cases continues to increase but in a less significant way because contacts are reduced .
However, the installation of a plateau is not synonymous with deconfinement, as Antoine Flahault, epidemiologist on France 2 : “It is not when we have reached a plateau that we must deconfinate when the measures have made it possible to avoid massive congestion in hospitals.” Even if the plateau is confirmed, it will in any case be patient before being able to return to a “normal” daily life.
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