During the first wave of the Covid-19 pandemic, cities were generally affected worse by small communities or rural areas.
But in Italy, Rome survived relatively while the villages of Lombardy suffered from very high rates of disease and death, but the remarkable thing for the scientists was the emergence of a single Lombardy village known as “Ferrara Erbognone” because no case of Covid-19 was recorded at the height of The wave is in it without knowing the reason for that.
The mystery of not recording any case of injury or death in a particular region is not limited to Italy. When the pandemic struck the countries of the world unevenly, the scholars stood to try to understand the reasons .. Why were some people more vulnerable to infection with the virus than others?
Virus protected groups
The neuroscientist working on a study of the models "Covid-19" Carl Friston of the University of London College suggested that the relatively low death rates recorded in Germany were due to unknown protection factors but we have to know them, according to the Observer last week, which is considered a destination New look.
While another point of view touched on the typical system of closure in Germany, it can be considered a factor in the low death rate.
With many views interfering with this, experts today stand before the mystery of identifying factors that modify the spread of "Covid-19" as a model of Japan that avoided a first killer wave of the virus despite its relatively elderly population and a somewhat weak public health response, which is This contradicts reports that indicate the death of "Covid-19" in the elderly as a result of weakened immunity and the presence of some diseases mainly in the patient.
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Another model is in Denmark, Austria and the Czech Republic that have not reported any increase in cases despite their early mitigation of the closure procedures.
So, and as a result, there are many reasons why people in some areas are more protected than others.
Theoretical epidemiologist Sunitra Gupta of Oxford University believes that the primary factor is the immunity that was created before the epidemic.
She says there is a lot of cross protection between severe illness and death, and although cross protection may not protect a person from infection in the first place, it can guarantee relatively mild symptoms.
What the epidemiologist talked about is intuitive because of a lack of data about immunity for Covid-19 before new antibody tests became more accurate in recent weeks.
T cells and their role in the formation of immunity
New research has shown that another component of the human immune response, T cells in the blood, helps to coordinate the antibody response and thus plays a key role in cellular immunity, where memory appears for coronavirus infection when exposed to "Sars-CoV-2", which is the virus Which causes "covid-19".
Researchers at the La Jolla Institute of Immunology in California reported that T cells in the blood taken from people between 2015 and 2018 recognize and interact with the Sars-CoV-2 virus, according to the British newspaper, The Guardian.
One of the sponsors of the research paper, Alessandro State, added that the most logical hypothesis is that this reaction is a reciprocal interaction with other strains of Sars-CoV-2 which are common coronaviruses that spread very widely and usually appear to the patient with somewhat mild symptoms.
The result supported a previous discovery from a group at the Charité Hospital in Berlin, the discovery of T-cell interaction with proteins in the Sars-CoV-2 virus in 83% of Covid-19 patients and also in 34% of healthy volunteers whose test results were negative from the same virus. .
On this point, the epidemiologist at the London School of Health and Medicine who advises the World Health Organization on "Covid-19" David Heyman says that these results are important, but that mutual interaction does not necessarily translate into immunity.
To determine if it is accurate, it requires tracking a large number of people who exhibit such mutual interactions to see if they are protected, and if not from infection with "Covid-19", then at least of severe forms of the disease.
Thus the hypothesis states that exposure to other coronaviruses can provide protection, and was presented on the H1N1 flu that appeared in 2009 as an example, where the elderly were in a good position compared to other age groups in this epidemic, perhaps because their immune system was prepared through exposure to strains Similar influenza from previous decades.
This may be the reason why the 2009 pandemic was less deadly than other influenza epidemics in history, which killed an estimated 200,000 people worldwide.
If exposure to other coronaviruses protects against Covid-19, then the variation in this exposure can explain the difference in mortality rates between countries or regions.
Thus, exposure to the SARS virus that caused the SARS epidemic in 2002-2004 may provide some protection for East Asia against Covid-19, for example.
Social and economic factors
Other factors interfere with securing immunity against the virus, such as the social and economic situation, climate, culture, and genetic makeup, as is the case with some vaccines that are received in childhood and vitamin D levels, which can vary between countries, and differences between the sexes play a role as it showed the presence of the X chromosome. Women have a stronger immune response to the virus.
Experts suggest that the Japanese may have been given some protection, for example, due to the habit of kneeling instead of shaking hands when greeting.
Lifestyle and its relationship to death rates in the elderly
Statistics showed significant differences in the number of deaths among the vulnerable or elderly who were infected with the virus, depending on the country depending on lifestyle.
For example, the elderly make up more than 20% of the population in both Germany and Italy, but the two countries reported significantly different mortality rates. As of May 26, the death rate of the elderly in Italy was about 14% compared to 5% in Germany.
Italy is more populated than Germany, and Italian homes tend to be smaller than German homes.
And still young groups of Italians live with their families in the same house, which means that the chance of transmission of the virus to the elderly is high, which is different in Germany, where the homes for the elderly imposed a strict isolation system in order to protect the elderly.
Some estimates indicate that only 20% of "Covid-19" cases in Germany were for people over the age of 60, compared to more than 90% in Italy.
Outcome of the models
Hayman is still wary of the models, and he warns against confusing them with the reality of the epidemic. We need more data and statistics. At the current stage, no one can predict the fate of this virus.