6. Countries and/or their regions face the epidemics

How to assess and compare the extent of the crisis? The varying size of populations undoubtedly has an impact on the number of deaths during the epidemic. The data available on this website also include population sizes by sex and age. Taking into account the different numbers at risk is a prerequisite in epidemiology for the analysis of diseases and mortality risk.

However, it is precisely this idea of exposure that raises the question: most probably because of the barrier measures and containment that limited the circulation of the virus, it was not the entire population of a country that was at risk of dying from COVID-19, but that of the regions where the epidemic broke out due to a combination of a triggering event (large-scale meetings) and stirring factors (population density, circulation, meetings). We do not provide data at a finer scale in this website, but we have carried out further analysis here for illustration purposes (regional data are available on the sites of the health agencies in the various countries).

It appears that the pandemic is acting in outbreaks like fires, whose lockdown and barrier measures have probably been successful in containing the spread to all regions, if not completely avoiding "fire outbreaks". The focus on regions more or less affected by outbreaks within countries, as proposed in the attached note, shows the value of changing the scale of analysis to better compare situations between countries.

This "geographic reference area" question is essential for those who wish to estimate mortality risks and assess the lethality of COVID-19. In France, for example, the two most affected regions account for 61% of all deaths (in hospital and institutions as published by SpF.), even though they represent only 26% of the French population. This approach shows, for example, that the situations in European regions which are more spared, or in the severely affected Ile-de-France, Grand-Est and Lombardy regions, are closer than French regions or Italian regions. Adjustment on the population at the regional level seems a prerequisite for a comparison of mortality risks. Such an exercise will be much more robust at the end of the epidemic when the publication of all deaths is finalised by the statistical institutes.

Tableau 6.1 Numbers and percentage of population of four French regions and France and cumulative deaths by COVID-19 published in these regions and France as of 16/04/2020. Regional data are available on the sites of the health agencies of the different countries

 Source : Points épidémiologiques national et régionaux du 16/04/2020. Santé publique France