What the virus figures say (and what they don't): why it is so difficult to judge the mortality from covid in Madrid and each community
17/12/2024This article by Borja Andrino, Daniele Grasso and Kiko Llaneras of May 3, 2021 highlights the fact that it is not always easy or obvious to interpret the data we have and more so in a disease as unknown as covid -19.
In the first place, we must not forget that we must always compare by sex and age group, especially in those diseases whose distribution we know (or assume) is different according to the age and sex structure of the population. This is all the more important if our objective is to compare between different countries, provinces, autonomous communities, municipalities, etc.
Let us remember that, as the authors of the article point out, covid-19 is a disease that occurs more frequently in older people. Therefore, those provinces where there are more elderly faced a greater risk.
On the other hand, we must not forget the fact that every epidemic tends to stop itself. As the authors argue, by increasing the percentage of infected people, the number of people susceptible to re-infection is reduced. To this we must add, the possible “harvest effect”. The virus is more lethal at first as it finds more people who are weak or vulnerable. Thus, all other things being equal, deaths will be lower in those areas most affected. Therefore, in waves subsequent to the first one, if our objective is to analyze mortality, it will be important to adjust it for the number of people likely to be ill at each moment.
However, even taking into account all the above factors, it is very complex to make judgments just by looking at the figures we have.
As we know, no two regions are the same and their characteristics make them more or less vulnerable. We have mentioned three variables, age, sex and the number of susceptible people, but it is easy to think that there are many more: the climate, the population density, the habits of the people, the measures imposed, their compliance, etc.
Thus, the only thing that is clear is that we must avoid drawing conclusive conclusions about the success of certain managers or of certain measures or decisions, since as experts remember, attributing causes is extremely complex.