How are we measuring the effects of the pandemia?

Politicians and the media are usually measuring the effects of the COVID-19 disease pandemic, caused by a coronavirus, by the number of positive cases detected, either the day before, or in the previous 14 days (number of cases per 100,000).

I believe that this is a mistake, as it makes it very difficult to make comparisons along the evolution of the pandemic, for the number of positive cases detected clearly depends on the number of tests carried out (the more tests, more positive cases will be detected), and since the number of tests carried out varies constantly, the data they provide cannot be compared.

Let's look at the data given over time by the Spanish ministry of Health. Figure 1 corresponds to the year 2020:

Figure 2 corresponds to 2021, up to August 31st:

The two figures have a common part (the days between December 1st, 2020 and January 27th, 2021), to make it easier to combine them. It will be noted that there have been six "waves" of the disease, although only five are officially recognized, because the second and third overlapped partially. We will use the official numbers here. It can also be seen that the smallest waves, according to these figures, have been the first and the fourth, when we all know that the worst was, by far and without any doubt, the first. But of course, at that time almost no tests were done, so the number of positive cases detected was much lower. Virtually no asymptomatic cases were detected, while this is now being done, as seen in Figure 2, which separates symptomatic cases (in dark green) from asymptomatic cases (in light green).

An attempt has been made to use the number of hospitalizations or the number of admissions to ICU as an element of comparison. At first glance, it seems logical, although there are also important differences over time, such as the progressive administration of vaccines, which seems to reduce a lot the number of hospitalizations (Figure 3 shows data from the USA):

Another piece of information that could be used to compare the evolution of the pandemic is the number of people who have died as a result of the disease. Figures 4 and 5 show the official data of the Spanish Ministry of Health, where these figures show the same common part as figures 1 and 2:

Here it can be seen that the worst wave of the pandemic was undoubtedly the first, followed by the third. The fourth and fifth have been much smaller, probably due to the influence of vaccination.

One interesting piece of information is the number of deaths due to vaccination, without having suffered from the disease. As I said in another post, I was on the verge of being one of those victims. I know of cases where deaths have occurred. These data are available for the United States. At the beginning of June, the number of deaths attributable to the vaccine was 25,800. Since, by then, about 150 million people had been vaccinated, the risk of death from vaccination was about 0.02%. In contrast, the number of deaths from COVID by that date in the United States reached 600,000 out of 33 million infected. Therefore, the risk of death by the disease was about 2%. I think it’s clear that it is better to get vaccinated, unless there are medical contraindications, for the risk turns out to be a hundred times lower than that of dying from the disease.

The same post in Spanish

Thematic Thread about Medicine and Linguistics: Previous Next

Manuel Alfonseca