Which early indicator allows for a better understanding of the evolution of the COVID-19 epidemic in France?

Loisel, P.

We provide an explanation for the apparent discrepancy between the dynamic of the positive COVID-19 test rates and of the numbers of COVID-19-related hospital and intensive care admissions and deaths in France. We highlight the existence of a latency period of around 5 weeks between the positive detection rate and the number of new admissions (in the exponential phase of the positive detection rate evolution). If the overall positive detection rate provided relevant information until the end of August, since the beginning of September the overall positive detection rate has reached a plateau and no longer provides relevant information on the current state of the epidemic. We show that the positive detection rate in the 70+ age group is a relevant and early indicator of the epidemic.