There are still countless uncertainties surrounding Covid-19 but, after almost a year of the pandemic, scientists are clarifying some features. As has been seen in people who have suffered from the disease, SARS-CoV-2 can leave serious consequences, whose infection will depend on a number of factors.

Diego Costa suffers a deep vein thrombosis in his right leg 2 months after testing positive for Covid

One of the most common sequelae, in fact, is the risk of thrombotic events. The leader of Vox Javier Ortega Smith, one of the first to be infected with coronavirus in Spain, had to be admitted again for several thrombi in the leg and lungs due to the coronavirus. More recently, soccer player Diego Costa suffers from a venous thrombosis in his right leg after rejoining Atlético de Madrid, after overcoming the virus two months ago.

There are numerous studies and investigations that have focused on these effects that are appearing in patients who were hospitalized for coronnavirus. The latter, carried out by scientists from the University of Michigan and published in the journal Science on November 18, sheds light on the causes of this pathology. “Patients with COVID-19 are at high risk for thrombotic arterial and venous occlusions”, concludes the study.

In fact, the researchers point out in the document that half of the patients hospitalized with coronavirus in very serious condition had “a combination of high levels of dangerous antibodies and super activated neutrophils, which are destructive and explosive white blood cells.” The same researchers already warned in April that many patients hospitalized with Covid-19 had high levels of calls extracellular neutrophil traps in blood, the remains of which may contribute to generating a “prothrombotic medium”.

The culprit: an antibody that affects half of patients

Ultimately, the culprit is an autoimmune antibody that circulates in the blood, attacks cells, and triggers clots in arteries, veins, and microscopic vessels. “Blood clots can cause life-threatening events like strokes. And, in COVID-19, microscopic clots can restrict blood flow in the lungs, affecting oxygen exchange, “they say.

These antibodies are usually seen in patients who have the autoimmune disease antiphospholipid syndrome, so “the connection between autoantibodies and COVID-19 was unexpected,” according to study co-author and assistant professor at the Frankel Cardiovascular Center of Medicine in Michigan, Yogen Kanthi, in the release press. “In patients with Covid-19, we continue to see an incessant and self-amplifying cycle of inflammation and clotting in the body” -adds Kanthi- “Now we are learning that autoantibodies could be to blame for this cycle of clotting and inflammation It makes people who were already fighting even sicker. “

Half of hospitalized patients with Covid-19 tested positive for at least one of the autoantibodies

“The half of hospitalized patients with Covid-19 they tested positive for at least one of the autoantibodies, which was quite a surprise, “says Knight, one of the leading experts in diseases caused by autoantibodies.

Following the April investigation, the scientists decided to ethoroughly study those neutrophils and antibodies in mouse models, to see how dangerous that combination was. “Antibodies from patients with active COVID-19 infection created a surprising number of clots in animals, some of the worst clots we’ve ever seen “, Kanthi says. “We have discovered a new mechanism by which COVID-19 patients can develop blood clots.”

Now, they assure that the next step is find out what causes the body to make these antibodies and identify triggers. “We are now investigating how long these antibodies remain in circulation after recovery from the new coronavirus,” Knight explained.

A common consequence of viral outbreaks

Another research published in September in ‘Journal of the American College of Cardiology‘presents a series of causes and possible actions that medical professionals can carry out in patients with this type of sequelae. In the document, the medical journal points out the study that was carried out on 184 Covid patients in critical condition, of which 31% had a thrombosis, and most of the events were venomous thromboembolism (VTE).

“The factors involved may be the release of inflammatory cytokines and critically ill disease and / or underlying risk factors.”, they point out in the document that exposes a pyramid with the possible pathologies that a patient who has been exposed to the virus suffers after its overcoming. “SARS-CoV-2 binds to cells that express the angiotensin-converting enzyme 2, and this may intervene in the subsequent mechanisms of injury production,” they add, noting that thrombotic and thrombembolic events are usually common during viral outbreaks.

Variability in resources and testing strategies and in the spread of COVID-19 after exposure to SARS-CoV-2.
Variability in resources and testing strategies and in the spread of COVID-19 after exposure to SARS-CoV-2. (DIC = determined intravascular coagulation)
Journal of the American College of Cardiology

More likely in hypertensive, diabetic and obese patients

According to the president of the Spanish Society of Cardiology, Ángel Cequier, to Europa Press, in the scene of Covid-19, 80% of thrombi occur in the venous system and they are usually generated in the lower extremities, or already in the lung, in the pulmonary artery or in its branches.

A Covid-19 patient at the Navarra Hospital Complex.
The coronavirus causes its most serious damage when it attacks the blood vessels

Likewise, the risk of suffering from thrombosis is greater in those patients infected by the coronavirus who suffer from a basic cardiovascular disease, hypertension, diabetes, or obesity, according to a report from the Coronavirus Scientific Analysis Group of the Carlos III Health Institute on coagulation problems and thrombi in patients with Covid-19.