Do Covid Pockets in the Gut Cause Long-Term Symptoms? † Long Covid

sSince the early days of the pandemic, it has been clear that some people have been losing genetic material from the virus in their stools for months after contracting Covid-19. The findings were initially considered curiosity, but there is mounting evidence to support the idea that persistent amounts of coronavirus – in the gut or elsewhere – could contribute to long-term Covid.

Earlier this month, Prof. David R Walt and colleagues from Harvard Medical School announced that they had detected Sars-CoV-2 proteins — most commonly the viral spike protein — in the blood of 65% of long-term Covid patients they treated. tested, up to 12 months after they were first diagnosed.

Though small and preliminary, the study provides some of the most compelling evidence yet for the idea that reservoirs of the virus could contribute to people’s long-term ill health. “The half-life of spike protein in the body is quite short, so its presence indicates that there must be some sort of active viral reservoir,” Walt said.

Spike protein was not detected in the blood of Covid patients who had no persistent symptoms.

Walt was motivated to conduct the study after earlier research by his colleagues detected Covid virus genetic material (viral RNA) in stool samples from children with multisystem inflammatory syndrome (a rare but serious condition that often strikes about four weeks). after catching Covid) as well as spike protein and a marker of intestinal leakage in their blood. Treating them with a drug that reduced gut permeability led to rapid clearance of the spike protein and an improvement in their symptoms. Walt’s working hypothesis is that something similar could be going on in people with long-term Covid.

If other groups could replicate Walt’s findings, it would be “pretty much game over” for the idea that pockets of the virus were still not present in at least some long-term Covid patients, said Dr. Amy Proal, a microbiologist at the PolyBio Research Foundation, a US non-profit organization that supports research into complex chronic inflammatory conditions: “I personally see no mechanism by which the spike protein could persist for long periods of time without the virus [being present]†

Other groups have also found evidence that the virus is still present – called “viral persistence” – in patients who have recovered from Covid. In April, Ami Bhatt, of Stanford University in California, and colleagues reported that about 13% of individuals were still excreting viral RNA in their stool four months after contracting Covid, and nearly 4% continued to do so after seven months. These people also frequently reported persistent gastrointestinal symptoms such as nausea, vomiting, and abdominal pain.

“The question is whether the continued presence of the virus in the gut or elsewhere can tickle the immune system a bit and cause lingering symptoms,” Bhatt said.

Separate study, which analyzed gut tissue from 46 people with inflammatory bowel disease who had recovered from mild Covid, found that viral RNA or proteins could still be detected in 70% of them seven months later. About two-thirds of these individuals reported persistent symptoms such as fatigue or memory problems, while none of those without detectable virus did.

Still other preliminary research has recovered viruses — in some cases replicating virus — from other anatomical sites, including the eyes, brain and heart, many months after humans became infected.

Viral persistence is also seen in other diseases, such as Ebola, where the virus hides in “anatomical sanctuaries” such as the eyeball or testicles that are less accessible to the immune system – and are thought to contribute to persistent symptoms such as joint pain and muscle aches, or fatigue, in many survivors.

Still, definitive evidence that viral reservoirs contribute to long-term Covid is lacking, and Bhatt would like to see further studies done before coming to this conclusion.

Some of these are already taking place. For example, the US National Institutes of Health’s Recover study looks for signs of coronavirus in stool samples and intestinal tissue from people with long-term Covid. “Studies like this will be critical to begin to unravel what the relationship between long-term viral reservoirs and long-term Covid might be,” Bhatt said.

If viral persistence really causes at least a subset of people’s symptoms, it could also spur research into antiviral drugs as a treatment for long-term Covid. While this may sound like a no-brainer, some virologists are concerned about its implications.

“The idea of ​​giving people long-term antiviral monotherapy to try and get rid of the virus is quite a controversial issue because given the degree of adaptation of the virus that we see even in a short period of time, the chances of the virus escaping are extremely high. is,” said Dr. Deepti Gurdasani, a clinical epidemiologist at Queen Mary University, London. “I think we really need to start thinking about double or triple therapies and try them out because we can’t really afford to create more escape mutants right now.”

Whether examining tissue samples or trials of antiviral drugs, for those who have been living with Covid for a long time, some for more than two years, such studies cannot come soon enough.

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