Predicting and treating the long Covid is still a difficult task for doctors and patients. But research is slowly progressing on the long-term sequelae left behind by the coronavirus. Researchers have identified four risk factors associated with long Covid.
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[EN VIDÉO] Long Covid: when symptoms last for months Many people have long Covid, a form of the disease that can stretch for months. © Futura
Between 30 and 60% of patients with Covid-19 suffer from sequels in the long term, according to the various studies that have looked into the subject. Very varied sequelae which, combined, form what is called the long Covid. Memory loss, gastrointestinal disturbances, chronic fatigue, shortness of breath, anosmia prolonged are as many symptoms long covid patients report to doctors.
The long Covid is linked to the severity of the initial infection since the majority of the people concerned leave the hospital or intensive care. Nevertheless, more moderate forms of Covid can also leave traces. The great diversity of symptoms of the long Covid, often amplified by comorbidities pre-existing, complicates the diagnosis, but also the work of researchers who are trying to understand the mechanisms at play in long Covid and the factors that favor it.
In the review Cell, an international team of researchers says they have identified several factors linked to Covid-19 by following 309 patients for three months. Four risk factors present at the time of screening make it possible to anticipate the appearance of the long Covid: a diabetes type 2, a strong viremia, the presence of autoantibodies and the reactivation from virus Epstein–Barr (EBV).
Four early factors associated with long Covid and its symptoms
Among the 309 patients included in the study, 14% presented with EBV reactivation and 25% with high viremia for the SARS-CoV-2 at the time of clinical diagnosis. At three months post-diagnosis, these two viruses are no longer detectable. Patients affected by the presence of these two viruses have reported memory problems and abnormal fatigue.
Autoantibodies are suspected of participating in the appearance of the Covid long. They were detected in 56% of patients included in the study at the start of follow-up, and again in 44% of patients after three months. Yet only 6% of patients told doctors they had an autoimmune disease before contracting Covid-19. The presence of autoantibodies and the nature of specific SARS-CoV-2 antibodies are linked to certain symptoms of long Covid. For example, patients with neurological disorders have more anti-nucleocapsid IgG while those with gastrointestinal problems have more autoantibodies at three months post-diagnosis. The autoantibodies directed against inteferon-α2 are, for their part, only linked to the respiratory symptoms of long Covid. All this suggests that the presence of autoantibodies and their nature at the time of diagnosis could predict the nature of future symptoms. Finally, type 2 diabetes is associated with certain symptoms of long Covid, such as fatigue and cough. Among the patients in the study, 22% had type 2 diabetes at the time of contracting Covid.
These elements could be used to follow the evolution of the sequelae of Covid-19 and possibly help doctors to prevent and treat them. Nevertheless, scientists have not put forward a causal link between these factors and long Covid, these are observations that allow scientists to better understand the disease. In other words, having a diabetes type 2 or autoantibodies does not mean that a person with Covid-19 will definitely have long-term sequelae. As long Covid is a protean condition, further studies will be needed to consolidate the results of this one.
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