It is known that the disease caused by the new coronavirus, known as covid-19, has had a greater incidence in large urban centers, where the concentration of people is greater and the possibilities of transmission of the virus grow accordingly. It is an airborne disease, so the main recommendations to prevent contagion are to wear masks and maintain physical distance.
In Venezuela, the entity with the most positive cases of covid-19 is the Capital District, which as of November 12, 2020, the reference date for the writing of this article, accumulates 20.510 cases of the 96.140 infections reported in the country. This represents 21,3% of the national total.
However, it is interesting to know the contagion figures for each region in relation to its population. In this way, the proportional impact of the pandemic in each case can be understood. The absolute numbers are important and indicate the epidemiological behavior of the virus, but the proportions reveal data that sometimes go unnoticed. It is said a lot that the numbers of infections in a country like China, which has almost 1.400 billion inhabitants, cannot be compared with practically any other nation. Or that there are not the same 1.000 cases of coronavirus in a city like New York, with more than 8 million inhabitants, than that number of infections on an island like Saint Kitts and Nevis, whose total population is less than 55 thousand people.
Let's go to the beach?
To determine the proportional impact of a disease there is a metric in Epidemiology called Prevalence Rate, or simply Prevalence. This is defined as the "proportion of the population that has the disease studied at a specific time", according to Mayra Cartín Brenes in her book "Epidemiology and Demography" (1990). It is calculated by dividing the number of infections by the number of individuals that make up the respective population. This will always return a value between 0 and 1, since it is a proportion. It can be multiplied by 100 and expressed as a percentage.
We decided to calculate the prevalence of covid-19 in each federal entity to better understand how the virus has geographically impacted our country. We divide the number of infections in each state, updated to Thursday, November 12, 2020, according to the reports made daily by the Presidential Commission to Combat Covid-19, among the corresponding population according to the projection for 2020 made by the National Institute of Statistics (INE).
Let's see the graph with the data. For a better understanding of the information, the prevalence is expressed in cases per thousand inhabitants. This is obtained by multiplying the number obtained by dividing the original values by 1.000.
It should be noted in advance that the data expressed here are referential and its intention is to carry out an analytical exercise on a particular variable. It is not intended here to point to any region, much less establish diagnoses. Epidemiological conditions depend on many factors, and their expression responds to complex procedures whose responsibility is the exclusive responsibility of the competent authorities, who provide timely information and establish the appropriate routes to follow.
The entity with the highest prevalence is the state of La Guaira, with a magnitude of 0.0127. This means that, out of every thousand Guaireños, 12,7 contracted the virus between March 13 and November 12. Or what is the same: 1,27% of the inhabitants of La Guaira tested positive for covid-19.
This region of the central coast, with 4.865 cases, surpasses the Capital District in this metric, which, although it tops the list of infections in absolute terms with 20.510, occupies the second place in terms of cases per thousand inhabitants (9,8).
For reference, in the image we highlight in yellow the data corresponding to the entire country. The national prevalence is 2,9 cases per thousand inhabitants.
It is logical to think that the greater the concentration of people in a territory, the greater the possibility that the virus will spread more quickly. That is why many scholars have placed population density as an important variable when analyzing the pandemic. According The Confidential, the British Dave Babbitt, Patrick Garland and Oliver Johnson, supported by the University of Bristol, presented a report to the science commission of the UK parliament, where they demonstrated that density plays an important role in the evolution of the pandemic. They gave as an example the city of New York or the case of Spain, whose population is concentrated in 13% of the territory, according to a report by rtve.es.
For this reason, we decided to add the population density data for each entity to the previous graph. In this way we can observe how much is the correspondence between the two variables. Let's see:
We can observe that the population density shows a direct relationship with the prevalence of covid-19 in the case of the Capital District. However, by itself this variable does not explain why the state of La Guaira shows a higher rate of infections per thousand inhabitants than the city of Caracas, even though the latter has a population concentration almost twenty times higher.
Analyzing the data we can also see that, for example, the third place in prevalence is occupied by the state of Apure, with 8,6 cases per thousand inhabitants, which, however, has one of the lowest rates of population density, with 6 inhabitants per square kilometer.
We can also highlight the case of the Aragua state, which has a population density similar to that of La Guaira and, nevertheless, is ranked 11th in terms of covid-19 prevalence, with 2,3 cases per thousand inhabitants.
Between both entities are regions such as those mentioned (Caracas and Apure), but also Nueva Esparta (6,0), Táchira (5,7), Yaracuy (5,4), Amazonas (3,7), Miranda (3,7, 3,2), Delta Amacuro (2,5) and Mérida (7). Nueva Esparta and Miranda have a higher population density than Aragua, but it is striking that there is a higher ratio of cases per number of inhabitants in a state like Amazonas, which has the lowest density in the whole country and, however, is located in the 19th in prevalence of covid-514. There is also the case of Carabobo, which has a higher population density than Aragua, with 19 inhabitants per square kilometer, and is ranked XNUMXth in prevalence.
The population density of Venezuela is 30,1 inhabitants per square kilometer. And, as we have already pointed out, it has a prevalence of 2,9 cases per thousand inhabitants, ranking between 10th and 11th.
The foregoing does not undermine the importance of population density, but it suggests that this variable alone does not explain epidemiological behavior, but is part of a broader set of elements that should be studied. In fact, according to the aforementioned note by El Confidencial, “British researchers themselves point out in their work that density is one more factor that can be related to others such as income or the interaction of the population of those places to explain why the The virus hits harder in some areas than in others, but it should not be ignored ”.
Better in the center
Just as we indicated the entity where the coronavirus has hit the hardest, the data analyzed allow us to highlight the state with the least impact.
This is Guárico, a plains state located in "the heart of Venezuela", that is, in the heart of the national geography. With 668 cases, it has a prevalence of 0,7 infections per thousand inhabitants, ranking last. With a population density of 11,5 inhabitants per square kilometer, it is the fifth least populated state in the country.
The characteristic of this entity is that it is far from all borders, which can provide more information than it seems. If we take into account that of the 10 states with the highest prevalence, 5 are border states, we may be facing a fundamental factor. In this way, the case of Amazonas is better understood, which being the least populated state should have a much lower prevalence rate, but it is located on the border, which places it in a vulnerable condition due to migratory movements.
And here it is convenient to make an important clarification. It must be taken into account that the contagion figures in the border states: Táchira, Zulia, Apure, Bolívar, are strongly affected by migration. The Venezuelan authorities have permanently indicated that many of the cases in these entities correspond to “imported cases”. That is, they are people who have entered the borders already infected with the virus. These citizens, although they can go to any entity in the country, when entering through a particular entity they are registered as contagions in that territory. That is why this factor must be taken into account when assessing the figures for these states.
In this way, we better understand the situation in Apure state, which, as we have pointed out, has a significant prevalence rate compared to its population density. Even the state of Lara, which is not a border, can see its figures affected by the migration factor, since the authorities reported that many patients who entered through the border with Colombia were transferred to a point of care located in the Larense entity and there they were made the diagnosis.
In any case, the behavior of the SARS-Cov 2 virus depends on multiple factors. Population variables are part of a broad set of elements that must be jointly evaluated, as has been pointed out by institutions such as the World Health Organization and recognized academic and scientific research entities, who have the authority to point out the routes to follow. to contain the spread of disease. These data have only referential intentions to encourage analytical views of this important topic for everyone.
In this sense, we share here a table with all the data used in this work, so that others can use them and thus develop their own analyzes.