There are 7 different forms of mild Covid-19

In addition to having identified several forms of mild Covid-19, a study shows that the coronavirus leaves a sort of fingerprint in the blood of convalescents. Valuable information to better understand the disease and to develop effective vaccines

There are seven different forms of Covid-19 disease, when its course is characterized by mild symptoms. This was reported by a new study by the team of researchers at MedUni Vienna, according to which the infection with coronavirus, when slight, would manifest itself in seven different shapes, leaving behind significant changes in the immune system, even after 10 weeks. These results, just published in the magazine Allergy, could provide valuable and useful information for the treatment of coronavirus positive patients and the development of a vaccine effective anti-Covid.

To identify the different forms of the disease, the researchers involved 109 coronavirus positive patients and 98 healthy subjects (control group). From here, they were able to show that i symptoms associated with Covid-19 occur in seven distinct groups: there are symptoms flu-like, such as fever, chills, fatigue and cough, symptoms similar to the cold, such as rhinitis, sneezing, dry throat and nasal congestion, symptoms of joint and muscle pain, and inflammation of the eyes and mucous membranes. And again: the symptoms related to lung problems, with pneumonia and shortness of breath, gastrointestinal problems, such as diarrhea, nausea and headache and, finally, the loss of smell e of taste. “In the latter group we found that loss of smell and taste predominantly affects individuals with a young immune system, which we measured by the number of immune cells, T lymphocytes, produced in the thymus [ghiandola che ha il compito di garantirne la maturazione, ndr]”, explains the immunologist and co-author of the study Winfried F. Pickl. “This means that we were able to clearly distinguish the systemic forms (for example the first and third groups) from the organ-specific ones (such as groups 6 and 7) of Covid-19”.

In the study, the researchers also observed a kind of fingerprint of the coronavirus. In fact, they have shown how Covid-19 infection leads to detectable changes over a long period of time, about 10 weeks, in the blood of convalescents. The analyzes, for example, showed that the number of neutrophil granulocytes, a type of white blood cell involved in the body’s defense against bacterial and fungal infections, was significantly lower than normal. “However, we observed that memory cells were developed and that the T cell Cd8 remained active “, says Pickl. “This indicates that the immune system it is still heavily involved even several weeks after the initial infection. At the same time, the regulatory cells (which have a fundamental role in preventing immune reactions, ed) have significantly decreased ”. This is likely a dangerous mix, the researchers warn, as it could lead toautoimmunity.

Furthermore, the data showed that the blood of convalescents had increased levels of immune cells producing antibodies: the higher (higher and longer lasting) the patient’s fever during the course of Covid-19, the higher the levels of antibodies against coronavirus. “Our findings contribute to a better understanding of the disease and help us develop potential vaccines, as we now have access to promising biomarkers and can perform even better monitoring. “, scientists point out. “The study shows that the immune system human ‘doubles’ when it defends itself against Covid-19 with the combined action of immune cells and antibodies and that the cells are also able to memorize the virus’ moves and respond. Now we have to confirm these results to use them in the development of effective vaccines ”.

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