An evil that researchers are beginning to understand better. Two recent studies offer possible explanations for the causes of long Covid, a syndrome whose mechanisms are still mysterious: one evokes the joint effect of sequelae in several organs and the other, a mechanism at the level of neurons.
More than 250 patients studied
There is “concrete evidence that different organs undergo changes” after a Covid-related hospitalization, said Christopher Brightling, co-author of a study published Friday in the Respiratory medicine with lancets.
This work is based on MRIs performed on 259 patients who were hospitalized for Covid in 2020-2021. They were compared with tests carried out on about fifty people who had never been infected.
“Our work highlights the need for specific long-term multidisciplinary follow-up services in relation to pulmonary and extrapulmonary health, particularly for people hospitalized with Covid-19,” emphasizes Dr. Betty Raman to SkyNews.
The brain, lung or kidneys affected.
Almost a third of Covid patients presented “abnormalities” in various organs, several months after leaving the hospital. These organs include the brain, lungs or kidneys and, to a lesser extent, the heart and liver.
Lung problems were, for example, 14 times more frequent and brain problems 3 times more frequent in patients suffering from long Covid or three times more common compared to other patients. The severity of the “abnormalities” identified varied greatly, depending on the age or general health of the patient.
The researchers identified, in particular, lesions in the white matter of the brain, a phenomenon that scientific literature can associate with slight cognitive impairment.
One of the study’s lead authors, Dr. Betty Raman, told SkyNews that people who have more than two organs affected are “four times more likely to suffer from serious, even very serious, physical and mental disorders.”
A possible explanation for long Covid
For the authors of the study, as well as for independent observers, these results open up a possible explanation for long Covid, that is, the persistence of lasting sequelae several months after infection.
This disorder, which however lacks a consensus definition, is still not well understood at a physiological level, with several competing explanations without necessarily being exclusive.
Friday’s study suggests that long Covid “is not explained by severe insufficiencies concentrated in a single organ,” but rather “by an interaction between at least two (different) organ abnormalities,” suggests pulmonologist Matthew Baldwin, who does not participated in it. matter of Respiratory medicine with lancets.
Altered neurons, according to another study
Another study, published a week earlier in the journal eBiomedicinerather, it opened the trail of a mechanism concentrated in the brain.
Led by a team from Inserm, this study examined around fifty patients, some of whom suffered a drop in their testosterone levels, related to an alteration caused by the virus in certain neurons that regulate reproductive functions.
The researchers then measured the cognitive functions of these patients, only to notice poorer performance when this category of neurons was affected.
These results “suggest that the infection can cause the death of these neurons and be the cause of certain symptoms that persist over time,” Inserm states in a press release.
More than 2 million French people affected
Fatigue, cough, difficulty breathing, intermittent fever, loss of taste or smell, difficulty concentrating, depression… long Covid is manifested by one or more symptoms from a long list, usually within three months after infection. infection and that persist for at least two months. Symptoms that cannot be explained by other diagnoses and that have an impact on daily life.
In France, “Long Covid” has affected 4% of adults or 2.06 million people over 18 years of age, with a small proportion (1.2%) reporting that they are severely hampered in their daily activities, according to a public health study carried out by France. It was conducted last fall and the results were revealed in June.
However, the vast majority of patients (90%) who suffer from long Covid see their symptoms slowly improve after two years, while the rest experience rapid improvement or, on the contrary, a persistence of their disorders, it states. A study published in May by Dr. Viet-Thi Tran, epidemiologist at AP-HP and professor at Paris-Cité University, regularly followed up 2,197 patients from the “ComPare” cohort who suffered from long Covid.
Source: BFM TV
