R0 calculation - RKI (German Public health) staying out of political controversy:
https://www.rki.de/DE/Content/InfAZ/N/NeuartigesCoronavirus/Situationsberichte/2020-05-10-de.pdf??__blob=publicationFile
The reproduction number, R, is defined as the mean number of people infected by a case
R can only be estimated based on statistical analyses such as nowcasting and not directly extracted from the notification system.
The nowcasting analysis and the R-estimate are based on all COVID-19 cases reported to the RKI with an illness onset up to 3 days before data closure.
Cases with a more recent illness onset are excluded from this analysis since their as yet low number would lead to unstable estimates.
The number of incident cases estimated using the nowcasting approach is presented as a moving 4-day average to compensate for random effects of individual days (Fig. 5).
With this approach, the point estimate of R for a given day is estimated as the quotient of the number of incident cases on this day divided by the number of incident cases four days earlier.
The current estimate is R= 1.10 (95% prediction interval: 0.90- 1,34) and is based on electronically notified cases as of 09/05/2020, 12:00 AM.
Today’s estimate of the reproduction number R is above 1.
Any interpretation of this number needs to take into account that the estimate is linked to a degree of uncertainty that is reflected by the prediction interval published daily alongside the actual number.
A low number of case reports could increase the statistical variation.
Thus, it is too early to infer whether the number of new infections will continue to decrease as in passing weeks or increase again.
The increase of the reproduction number R necessitates a close monitoring of the situation in the coming days.
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