For six months now, scientists and doctors have been trying to assess the damage Covid-19 does to the human body. However, despite more than 400,000 deaths, millions of recovered cases, and thousands of studies and reports, the picture is still not completely clear.
Data obtained by British researchers indicate that the primary symptoms of the disease can appear, disappear and reappear for 30 days or more, which is significantly longer than the official two-week period set by WHO experts. And for some, the disease may be just the beginning of a long and painful battle with the virus that can lead to a new “post-COVID syndrome.
According to the prestigious journal Science, this coronavirus “does things that no disease known to mankind has ever done before. As authorities tried one measure after another to stop the spread of the infection, and doctors searched (in vain) for a drug or vaccine to fight the disease, we learned new details about the coronavirus, and our understanding of it changed, in some ways dramatically.
At first it appeared to be a common respiratory illness like SARS or avian flu, but it was later discovered that the coronavirus (officially named SARS-CoV-2) can affect the lungs, brain, nose, throat, eyes, heart, blood vessels, liver, kidneys and intestines, literally every vital organ. According to the results of research already conducted, Covid-19 is associated with a variety of symptoms, and for those who have had a severe case, the long-term consequences can be the most serious: from scarring of lung tissue and kidney failure to inflammation of the heart muscle, arrhythmia, liver damage, cognitive impairment, psychosis accompanied by sudden mood changes, and much more.
The full long-term effects of the disease on people are not yet fully understood, but there is ample evidence to suggest that even those who have had a mild form of COVID-19 continue to experience the effects of the disease. There is another important question: can the SARS-CoV-2 virus remain dormant in the human body and not manifest itself in any form after several years? This is not surprising, say doctors, because there are known viruses that behave just like this.
For example, after a person has had chickenpox, the herpes virus that caused it does not go away; it can hide quietly for decades and then erupt as painful shingles when the opportunity arises. And the virus that causes hepatitis B can lead to liver cancer many years later. Even the Ebola virus, detected months later in the eye fluid of survivors, causes blindness in 40% of those infected.
Given the fact that SARS-CoV-2 prefers the lungs, doctors suspected that the virus was capable of causing irreversible changes there. In March, specialists at Wuhan University of Technology reported that computed tomography scans showed visible lung damage in 66 of 70 patients who developed pneumonia from Covid-19. In some patients, lung function may not fully recover. These injuries range from blockage of the blood vessels in the alveoli to scarring of the lung tissue. Such scarring, or thickening of the tissue, is called pulmonary fibrosis and can lead to shortness of breath. There is currently no way to stop or reverse this process.
“Fibrosis can stabilize and not change over time, that’s true. In some patients, lung function may not fully recover, but the consequences of this will not be so significant,” explains Professor Louise Wayne of the University of Leicester. “But there are also cases of progressive fibrosis, and that is really dangerous because sooner or later it kills. In addition, prior to the introduction of the strict quarantine in the UK, the Faculty of Intensive Care Medicine (FICM) – a professional medical organization responsible for training UK intensive care physicians – warned that patients with a severe form of Covid-19 could suffer such severe lung damage that recovery could take up to 15 years. FICM emphasized that many patients admitted to intensive care units developed acute respiratory distress syndrome (ARDS), a severe inflammation of the lungs in which fluid from the blood enters the alveoli, making it impossible to breathe without special equipment. Given the history of lung tissue damage in patients with SARS and MERS, a group of medical experts led by radiologist Melina Hossaini of the University of California, Los Angeles, strongly recommends that patients who recover from Covid-19 be monitored and their lungs examined “to assess long-term or permanent damage, including fibrosis.
When doctors try to assess the damage done to the various organs of patients who have had Covid-19, they are faced with a predictable problem: people with lung, heart, kidney or blood diseases were typically the first victims of the coronavirus, and in their case, the disease often progressed severely. As a result, it is not always possible to determine what the virus caused and what damage had already occurred. But one thing is clear: when the symptoms of infection begin to manifest, the functions of many organs are disrupted, and the failure of one leads to the failure of others. An acute inflammatory process that leads to strokes and heart attacks also plays a role.
The coronavirus can cause damage to the heart muscle and the formation of blood clots. According to the March report published in JAMA Cardiology, nearly 20% of the 416 patients studied in Wuhan hospitals had heart muscle damage. There, but already in the intensive care units, arrhythmias were detected in 44% of the 36 patients. Doctors associate this with hypercytokinemia, or cytokine storm, a potentially fatal response by the body that triggers uncontrolled activation of immune cells, leading to destruction of tissue at the site of inflammation. Such a reaction has been observed in some patients with coronavirus. In particular, it causes inflammation of the heart muscle (myocarditis), which disrupts electrical impulses, leads to arrhythmias, and impairs blood circulation, causing shortness of breath. Cardiovascular complications are not unique to Covid-19: myocarditis can be caused by many viral diseases. And although most patients recover, some damage to the heart muscle is irreversible.
Covid-19 also has a negative effect on the blood itself. Of 184 patients with coronavirus admitted to intensive care in the Netherlands, 38% were found to have increased blood clotting, and nearly a third had blood clots.
Although the coronavirus primarily affects the lungs, in some patients the infection has spread to the kidneys. According to selective studies conducted in China, 27% of 85 patients admitted to Wuhan hospitals with coronavirus had kidney problems. According to the results of another study, 59% of nearly 200 patients hospitalized in Hubei and Sichuan provinces had protein in their urine, indicating infection, and 44% had blood, indicating serious kidney damage. In addition, patients with acute renal failure (ARF) had a 5-fold higher risk of death than regular COVID-19 patients.
Scientists have not yet determined exactly how the coronavirus affects the brain. Of the 214 patients studied with Covid-19, one third experienced neurological symptoms, including dizziness, headaches and cognitive dysfunction. For now, scientists can only speculate about what exactly causes these symptoms. However, existing theories focus on how the virus affects neurons – nerve cells. These include the loss of taste and smell, inflammation (our immune system responding to the virus), and oxygen deprivation, which some patients experienced. Cognitive dysfunction can be associated with patients in intensive care, also called temporary mental confusion or delirium, when a person experiences hallucinations. However, it is more commonly observed in elderly people. And although symptoms usually resolve over time, some may persist.
According to doctors, the recovery of cognitive functions in individuals who have had COVID-19 depends heavily on age, comorbidity (which refers to the coexistence of two or more diseases or disorders in a patient), and the severity of the disease itself. According to Lynn Turner-Stokes, Professor of Rehabilitation Medicine at the Royal College of London, the virus can affect the brain even in patients with a mild form of the disease. And in the words of Professor Ed Bullmore of Cambridge University, we already have reason to believe that SARS-CoV-2 causes a “neurotoxic disease” that leads to “some kind of change in the mental state of the patient.
“We don’t know exactly what causes this neurotoxicity,” admitted Professor Bullmor. “It could be that the virus infects the brain, or perhaps our immune system’s response to the virus causes damage to the neurons, or maybe it’s the blood that enters the brain. At the moment, all these possibilities are possible. The following materials were used in this article: Independent, Los Angeles Times and Mail Online.