2023-09-25 19:40:00
Long Covid manifests itself three months after infection Freepik Two recent studies give clues about the causes of so-called long Covid, a syndrome governed by mechanisms that are still mysterious: one deals with the joint effect of sequelae on various organs, and the other, damage to neurons . There is “concrete evidence that different organs undergo changes” after hospitalization for Covid-19, declared at a press conference Christopher Brightling, co-author of a study published on Friday (22) in the journal Lancet Respiratory Medicine. See also Health Anvisa approves new medicine for diabetes Health Compound present in fruits and vegetables can help fight tumors Health Covid-19: research reinforces the safety of vaccines for pregnant women and babies The study is based on MRI scans performed on 259 patients who were hospitalized by the new coronavirus between 2020 and 2021. The results were compared with tests carried out on around 50 people who were never infected. About a third of Covid patients had “abnormalities” in multiple organs — the brain, lungs, kidneys and, to a lesser extent, the heart and liver — months after being discharged. The researchers observed, for example, lesions in the white matter of the brain, a phenomenon that scientific literature associates with mild cognitive loss. The study authors and independent observers believe that these results provide a possible explanation for long Covid, that is, the persistence of long-lasting sequelae months after infection. Long Covid does not yet have a consensual definition, and the hypothetical explanations are diverse, without being mutually exclusive. The study published on Friday suggests that long Covid “cannot be explained by serious insufficiencies concentrated in a single organ”, but that it is due to “an interaction between at least two anomalies” in different organs, says pulmonologist Matthew Baldwin, who did not participate in the study, in the same issue of Lancet Respiratory Medicine. Another study, published a week earlier in the journal eBiomedicine, paves the way for a mechanism concentrated in the brain. Conducted by a team from Inserm, the French health and medical research institute, this study looked at around 50 patients. Some of them suffered a drop in testosterone levels, related to a change in certain neurons that regulate reproductive functions. The researchers then measured the cognitive functions of these patients and found worse performance in those who suffered such neuron damage. These results “suggest that the infection may cause the death of these neurons and be behind certain persistent symptoms,” says Inserm. Fatigue, cough, shortness of breath, intermittent fever, loss of taste or smell, difficulty concentrating, depression… The symptoms of long Covid are abundant. In general, they appear within three months of infection and last for at least two months. Here, they are symptoms that cannot be attributed to other pathologies and that have an impact on everyday life. Read also Lack of diagnoses for Alzheimer’s worries experts One third of adults in the world suffer from high blood pressure; situation is worse in Brazil American doctors perform 2nd pig heart transplant in humans At least 90% of long Covid patients show, however, a slow improvement in symptoms after two years, while the rest have a quick recovery, or even a persistence of symptoms, according to a study published in May by epidemiologist Viet-Thi Tran, from the University of Paris Cité, based on 2,197 patients.
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