Among the factors that most contributed to the spread of the new coronavirus in the world are the low temperature of the place, a higher proportion of elderly people and a greater number of international tourists in the first days of the epidemic. This is what a study by Unicamp, in Campinas, found, which collected data from 126 countries to understand how covid-19 spread so quickly in the world. In Campinas alone, covid-19 killed 277 people and infected more than 7 thousand. (read more below)
The analysis, with support from Fapesp (São Paulo State Research Support Foundation), analyzed data from the initial phase of the epidemic, that is, before public policies were adopted to contain the contagion.
In addition to the factors mentioned at the beginning, the higher prevalence of lung cancer, cancer in general and COPD (chronic obstructive pulmonary disease) was also important; higher proportion of obese men; higher rate of urbanization, higher consumption of alcohol and tobacco; and greeting habits that involve physical contact, such as kissing, hugging or shaking hands.
“We chose as the starting point of our analysis the day on which each country registered the 30th case of COVID-19 and analyzed the following days [entre 12 e 20 dias, dependendo do país]. The objective was to understand what happened at the stage when the disease grew freely, almost exponentially “, explains to GAP FAPESP Agency, professor at the Physics Institute Gleb Wataghin (IFGW-Unicamp) and co-author of the article published on the medRxiv platform, still without peer review.
According to the researcher, the proposal was to apply statistical analyzes generally used in the area of ??physics, among them simple linear regression and the calculation of the coefficient of determination to try to understand what happened at the beginning of the pandemic. The data used in the analyzes came from several sources, much of it from a public repository known as Our World in Data.
“The idea was to evaluate the following: if nothing was done to contain the disease, how fast would the virus spread in different countries or in different social groups? Factors such as temperature, demographic density, urbanization and health conditions of the population influence the contagion speed?
LACK OF RELIABLE DATA
Some studies suggest that the BCG vaccine against tuberculosis may have some protective effect in the case of COVID-19. The analyzes made by researchers from Unicamp and the University of Barcelona indicate the existence of a weak correlation between the two variables (rate of immunization against tuberculosis and rate of contagion by SARS-CoV-2). According to Torrieri, however, it is possible that the result was harmed by the lack of reliable data in countries where vaccination is not mandatory.
Among the factors analyzed that did not correlate with contagion (neither positive nor negative) are: number of inhabitants; prevalence of asthma; population density; vaccination coverage for polio, diphtheria, tetanus, whooping cough and hepatitis B; prevalence of diabetes; level of air pollution; number of holidays; and proportion of rainy days. In the case of GDP (Gross Domestic Product) per capita, as explained by Torrieri, the correlation was positive only in amounts above 5,000 euros.
“GDP is related to the quality of public infrastructure. The higher the GDP per capita of a country, the better the health and housing infrastructure, for example. But below 5,000 euros it probably didn’t make a difference because the infrastructure is low quality “, evaluates the researcher.
Although it is impossible for countries to change some of the variables studied, such as climate, life expectancy and the proportion of elderly people, for example, their influence on the spread of the disease must be taken into account in the formulation of public policies, helping to define strategies testing and social isolation, they argue.
Other variables, according to the authors, can be controlled by governments: testing and isolation of international travelers; restriction of flights to regions most affected by the pandemic; promoting habits of social detachment and campaigns to reduce physical contact while the virus is spreading; and campaigns aimed at stimulating vitamin D supplementation in the population, reducing smoking and obesity.