4. Dating the beginning of the epidemics
As the pandemic did not affect countries at the same time, one of the first recommendations is to align the curves with dates corresponding to the beginning of the epidemic and to identify key associated health events (F. Robin-Champigneul). There is no convention for declaring the initial day of the epidemic: it seems that countries are in a very close dynamic before the accumulation of a hundred or so known deaths. However, the very first deaths are difficult to date; it is necessary to wait for a certain accumulation to consolidate the take-off of the epidemic.
Following the work of the note cited above, this website refers to the day of publication of the 25th death by COVID-19, which corresponds to the point of take-off of the epidemic in most countries. Which day of the epidemic corresponds to? After checking on several countries, it is numbered by convention "Day 9". There are some exception, such as the Republic of Korea, for which the beginning of the epidemics is dated as the day of two first deaths, because no take-off point can be identified (Table 1.1).
Table 1.1 Dates at which countries have reached 25 total death by COVID-19 and estimated day of epidemics start (F. Robin-Champigneul)
| Date at which total reached 25 deaths (total deaths known at this date) | Day of epidemics start | |
| Germany* | 17/03 (26-29 known deaths*) | 9/03 |
| Denmark | 22/03 (25 known deaths) | 14/03 |
| Spain | 08/03 (35 known deaths) | 29/02 |
| France | 09/03 (30 known deaths) | 01/03 |
| Italy | 29/02 (29 known deaths) | 21/02 |
| Netherlands | 14/03 (27 known deaths) | 6/03 |
*For Germany, counts comes from Zeit et du Berliner Morgenpost publication while RKI, changed its counting systems and did not published information between march 14 and 19th, steping from 12 to 37 deaths..
**For the Republic of Korea, or any countries where the pandemics did not really take off, the beginning of the epidemics is set at 2d death.