Coronavirus en Allemange, situation au 21/06/2020 : R effectif moyenné sur 4 jours à 2.88, et R moyenné sur 7 jours supérieur à 2▻https://www.rki.de/DE/Content/InfAZ/N/Neuartiges_Coronavirus/Situationsberichte/2020-06-21-en.pdf
Estimation of the reproduction number (R)
The presented case numbers do not fully reflect the temporal progression of incident COVID-19-cases, since the time intervals between actual onset of illness and diagnosis, reporting, as well as data transmission to the RKI vary greatly. Therefore, a nowcasting approach is applied to model the true temporal progression of COVID-19 cases according to illness onset. Figure 2 shows the result of this analysis.
The reproduction number, R, is defined as the mean number of people infected by one infected person. R can only be estimated based on statistical analyses such as nowcasting and not directly extracted from the notification system.
The sensitive R-value reported can be estimated by using a 4-day moving average of the number of new cases estimated by nowcasting. This 4-day value reflects the infection situation about one to two weeks ago. This value reacts sensitively to short-term changes in case numbers, such as those caused by individual outbreaks. This can lead to relatively large fluctuations, especially if the total number of new cases is small. The current estimate of the 4-day R-value is 2.88 (95%-prediction interval: 2.16 – 3.73) and is based on electronically notified cases as of 21/06/2020, 12:00 AM.
Similarly, the 7-day R-value is estimated by using a moving 7-day average of the nowcasting curve. This compensates for fluctuations more effectively, as this value represents a slightly later course of infection of about one to a little over two weeks ago. The 7-day R-value is estimated at 2.03 (95% predictation interval: 1.60 – 2.49) and is based on electronically notified cases as of 21/06/2020, 12:00 AM. In light of the still low daily case numbers, both R-values should be interpreted with caution and in their course over several days.
Estimates of the reproduction numbers (R-value and 7-day R-value) were between 2 and 3 during the last few days. This is mainly related to local outbreaks which are described above, the outbreak in North Rhine-Westphalia playing a particularly important role in this context . Since case numbers in Germany are generally low, these local outbreaks have a relatively strong influence on the value of the reproduction number. Further developments need to be monitored closely during the upcoming days, especially in regard to whether case numbers are increasing outside of outbreak contexts.
Ce qui est intéressant, c’est qu’en Allemagne, ils n’utilisent pas l’alibi « R effectif augmente simplement parce qu’on fait plus de tests », mais en revanche ils insistent sur le fait qu’il y a de gros clusters en ce moment.
Pour le coup, on pourrait s’étonner de dédramatiser l’évolution de l’épidémie au motif que ce qui fausserait le chiffre, c’est qu’il y a soudainement énormément plus de contaminations… (c’est l’autre explication en France, moins mise en avant : « les chiffres sont faussés parce qu’il y a des clusters… »). Alors qu’on pense désormais que les « clusters » sont le principal facteur initial qui détermine l’extension de l’épidémie (par exemple : grosse célébration religieuse qui va pourrir la situation d’un pays ou d’une région entières pendant plusieurs semaines après).
