How many are still coughing, lost in thought or still have not regained their sense of taste and smell, two years after being infected with Sars-Cov-2? More and more studies show that long-term Covid-19 disease persists in many people for up to 24 months after a first infection, or even longer. A phenomenon still very poorly understood, while scientists have not yet found any cure or established explanations for the long Covid.
Indeed, few are those who quickly get rid of their long Covid, according to a French study published in International Journal of Infectious Diseases on May 12. As part of ComPaRe, a Paris Hospitals research project aimed at improving knowledge of chronic disease, scientists led by epidemiologist Viet-Thi Tran followed 2,197 patients diagnosed positive for Covid for more than two years. -19, or have strong reason to believe they have been infected.
Result: only 4% of them saw their condition improve rapidly, until they achieved complete remission of symptoms within two years of their onset. Conversely, 5% of patients saw their condition almost unchanged during this period. The vast majority, i.e. 91% of the remaining patients, saw a very slow improvement in symptoms over time, with a reduction in the number of disorders observed, without necessarily going into remission. To arrive at these results, the patients had to answer questionnaires every 60 days during the duration of the study.
Another recent study, published in the Journal of Clinical Medicine also shows the large proportion of “very long Covid”, especially among those who have developed severe forms. The more limited population observed consisted of 121 patients who had been hospitalized in San Donato, in an Italian clinic, for an acute phase of the disease. 60% of them on average have had symptoms for at least 17 months. The most common ? Intense fatigue and breathing difficulties. Cognitive disorders, the famous “brain fog” which prevents some from concentrating, would have persisted in 30% of patients.
A difficult diagnosis
Difficult, however, to establish general laws on the long Covid. The studies are based on subjective assessments of the disease, and not objective measurements, which profoundly slows down research and prevents any extrapolation. “No one disputes the medical reality of the long Covid any longer, but today it remains a diagnosis of elimination. We have no positive diagnostic marker that would allow us to be 100% sure that someone is suffering from this syndrome, and not from another chronic disease”, explained to us in March Jérôme Larché, doctor “referent Covid long” at the ARS of Occitanie.
While the WHO lifted the maximum alert on Covid-19 in early May, the long Covid still claims many victims around the world. “We must not forget that many people continue to suffer from this disease. We must show solidarity, and seriously consider the care of these patients, even if the disease is polymorphic, which makes research much more difficult “, indicated to L’Express Antoine Flahault, epidemiologist at the Institute of Global Health in Geneva, a few weeks ago.
While WHO boss Tedros Adhanom Ghebreyesus recently pointed out that one in ten infections seemed to result in a long Covid, and a need for long-term care, this proportion seems to be decreasing over time. , according to a series of recent studies. Good news that scientists are struggling, again, to explain. The hypotheses ? The new variants would result in long Covids less often. Or again: the population would benefit from a better immune response, in particular thanks to vaccines and previous infections.
If the long Covid still remains mysterious, several avenues are emerging to explain one or more of the symptoms identified, without it being known precisely what is happening in the body of the sick. One of the main hypotheses: all or part of the virus would persist in the organism, and could remain in the intestinal mucosaaccording to an Inserm study published in the journal NatureCommunications last March 30. For both patients and research, there is still a long way to go.