The long Covid – which would affect 10 to 15% of people who have contracted Covid-19 and whose origin is still unknown – could it be due to viruses hidden in the body thanks to reservoirs ? This is the hypothesis that Dr. David R. Watt, of the Harvard Medical School, and his team wanted to confirm.
In scientific preprint published on June 16, the researchers indicate that they have identified the Spike protein of SARS-CoV-2 in the plasma of two thirds of a panel of patients with long Covid. Conversely, this same protein was absent from Covid patients no longer showing any symptoms. Even though this study was conducted on a small sample of people – a cohort of 63 people of whom 37 were diagnosed with long Covid – the conclusions remain compelling. Of the 37 patients with persistent symptoms, 31 had this famous protein in their body. And among these 31 patients, 30 were women, thus confirming that the women are more affected by Covid long.
However, this discovery does not constitute a revolution in itself. But if this conclusion is confirmed, it could enlighten doctors to better treat this pathology: if the Spike protein is present in the plasma of Covid long patients, it means that the virus has found a way to pass into the blood, via “active virus reservoirs”.
Persistent gastrointestinal symptoms
A hypothesis already put forward in April and May 2022, when a Stanford University study discovered “ghost viruses”, i.e. fragments of SARS-CoV-2 RNA in the intestine of two thirds of patients suffering from long Covid, up to 7 months after an infection when they were no longer positive. patients who have often reported persistent gastrointestinal symptoms such as nausea, vomiting or abdominal pain. “The question is whether the lingering presence of the virus in the gut or elsewhere in the body can somehow tickle the immune system and cause lasting symptoms.”said lead researcher Dr. Ami Bhatt at the time.
At the same time, another study on the subject published in the journal Gastroenterology revealed that fragments of the Covid-19 virus were still present in the mucous membrane of patients with chronic inflammatory bowel disease (IBD) six months after their Covid infection.
A reservoir also observed in children
Finally, Dr. Walt’s research team had already observed the presence of a SARS-CoV-2 replication reservoir in children with a multisystem inflammatory syndrome after Covid infection. According to the researchers, the virus could have passed into the blood through a breach in the intestine, made too permeable by inflammation.
“In conclusion, the presence of a circulating peak in Covid patients long for up to 12 months after diagnosis strongly suggests that SARS-CoV-2 viral reservoirs persist in the body. Moreover, the detection of the peak in the majority of individuals included in our long Covid cohort provides strong support for the use of the peak as a biomarker.”conclude the researchers.
This new study supports several hypotheses which, if confirmed, could give hope for a more reliable diagnosis : the long Covid could be identified by a simple blood test to measure the presence of the protein responsible and better treatment strategies could finally be put in place in the patients concerned.
Source :
- Persistent circulating SARS-CoV-2 spike is associated with post-acute COVID-19 sequelae, MedRxivJune 16, 2022
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