It is a disease that affects between 5% and 15% of people who have contracted the disease. Covid-19 but whose origin and characteristics are still poorly understood. The long Covid can considerably impact the quality of life of people who continue to suffer from certain symptoms several weeks, even several months following their infection with Covid-19. Because they are still little studied and little documented, these sequelae can pass in the eyes of a part of the medical profession for psychosomatic symptoms.
However, as an article from the Guardianthere is growing scientific evidence to support the idea that persistent reservoirs of Covid-19 in some people’s bodies might be the reason they develop symptoms over the long term.
A team of researchers from Harvard Medical School announced in June having detected SARS-CoV-2 proteins in the blood of 65% of patients who reported continuing to suffer from symptoms of Covid-19, up to 12 months following their first diagnosis.
Or, “the viral spike protein has a short lifespan in the body. Its presence therefore indicates that there must be some sort of active viral reservoir. explained Professor David R. Walt. “I personally don’t see a mechanism by which the spike protein might persist for long periods of time without the virus [soit présent]», added Dr. Amy Proal, microbiologist at the PolyBio Research Foundation. Furthermore, the protein was not detected in the blood of patients who no longer showed symptoms.
For his research, the professor also drew on previous studies by colleagues at Harvard Medical School of children with multi-system inflammatory syndrome, a rare but serious condition that can strike young people four weeks following birth. Covid-19 infection.
These children were treated with a drug that reduced intestinal permeability, which caused them to rapidly clear the spike protein and improve their symptoms. The scientific team’s hypothesis is that something similar might happen in people suffering from symptoms of long Covid.
Virus persistence
Other research groups have also found evidence that the virus continued to be present in patients who are no longer positive for Covid-19. This is called “viral persistence”.
In April, doctor-researcher Ami Bhattune and her team at Stanford University reported that regarding 13% of these individuals were still excreting viral RNA in their stool four months following being infected with Covid-19, and that nearly 4% continued to do so seven months later. These people also often reported persistent gastrointestinal symptoms such as nausea, vomiting, and abdominal pain. “The question is whether the persistent presence of the virus in the gut or elsewhere in the body can, in some way, tickle the immune system and cause lasting symptoms,” explained the researcher.
Another research team, which analyzed the gut tissues of 46 people with inflammatory bowel disease who had been infected with Covid-19, found that viral RNA or proteins were still detectable in 70. % of them seven months later. About two-thirds of these people reported persistent symptoms, such as fatigue or problems with memory. Those whose virus had cleared from their bodies reported no symptoms.
Despite these various scientific works, the Guardian specifies that there is not yet definitive proof that viral reservoirs contribute to long Covid, and that other studies will have to be carried out before reaching this conclusion. They nevertheless have the merit of advancing research on a subject that affects thousands of people and who are still today in the most total vagueness.