Covid-19: How researchers are making progress on the mysterious “long Covid”.

Millions of people around the world are believed to be chronically suffering from Covid, and four years after the start of the epidemic, researchers continue to make progress in the “puzzle” of this post-infectious syndrome with hopes of getting better. Treatment of the sick.

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Long covid is the name given to various symptoms that usually appear within three months after infection.n and persisting for at least two months after infection with the SARS-CoV-2 virus, the most common of which are fatigue, shortness of breath, muscle pain, brain fog. While it is difficult to assess the number of people affected by this event, This would represent 10 to 20% of people who are infected with CovidAccording to the World Health Organization (WHO).

Many teams around the world are still working on the mechanism, diagnosis or treatment of this phenomenon. Some recent work shows progress.

“The Middle Piece of the Puzzle”

A study published in January in the journal Science showed significant differences in blood proteins in more than 110 patients with Covid, including 40 patients with symptoms six months after initial infection. That one “The Middle Piece of the Puzzle” To explain why Covid stays in some people’s bodies for so long, Onur Boymann, a Swiss researcher and lead author of the study, told AFP.

Part of the body’s immune system — the complement system, which normally fights infection by killing infected cells — apparently remains active, continuing to attack healthy targets and damage tissue, according to these researchers. According to Onur Boyman, the team found that when people recovered from Covid for a longer period of time, this complement system also improved. “This shows that prolonged covid is a disease and it is possible to measure it”The researchers added, raising hopes of identifying specific markers.

For Lucia, a longtime resident of the United States suffering from Covid who chose not to give her last name, “These types of studies bring us much closer to understanding the disease

“. Another recent study in patients with prolonged covid, published in Nature, found abnormalities in muscle tissue and dysfunction of mitochondria – sources of energy for the cell – which may explain the great fatigue of some.

Climbing the stairs to her apartment has become an ordeal.AFP says Lucia, who never imagined how long Covid would last “affects all aspects of a person’s life, including social and financial” and how much “distrust or rejection from the medical community or social circles” Sometimes added to health problems. The importance of support for patients is underlined by a study published this week in the British Medical Journal, which found that group rehabilitation improved the quality of life of patients suffering from post-Covid syndrome.

A long covid still remains elusive

The protection of vaccines against SARS-CoV-2 against the long-term risk of covid in adults and children has been confirmed by several recent studies. But, for the moment, long-term covid remains elusive because it is “multisystemic,” while “our brains are trained to think of diseases in terms of organ systems,” Ziad Al-Ali, a clinical epidemiologist at Washington University in St. Louis, told AFP. .

The causes may also be associated, or succeed each other in the same person, or vary from person to person.

Understanding the mechanisms of chronic covid may also help “Why and How Acute Infections Cause Chronic Diseases”, according to Ziyad al-Ali. This can thus strengthen the fight against other conditions such as chronic fatigue syndrome or persistent post-flu symptoms.

Especially since “In terms of climate change“, there may be “More and more emergence of infectious pathologyMany of which will lead to post-infectious syndrome“, warned Brigitte Autran, president of Covars, an advisory body that sent the French government an opinion on prolonged covid in November.

(Update with AFP)