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A small study suggests fecal transplants may help treat SARS-CoV-2 infection. AscentXmedia/Getty Images
  • Fecal transplants appeared to quickly and unexpectedly resolve COVID-19 symptoms in two people with Clostridioides difficile infections.
  • Transplants of healthy stool can restore bacterial health in the gut.
  • Although two individuals constitute a tiny sample, the outcomes suggest that further research may be warranted.

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Doctors who performed fecal microbiota transplants (FMTs) to promote healthy gut bacteria in two people with persistent Clostridioides difficile infections (CDIs) observed an unexpected resolution of COVID-19 symptoms.

It is not clear whether or not the FMTs were responsible, and two such cases are not enough to draw hard conclusions. However, the apparent response of COVID-19 to the FMTs suggests that further investigation may be necessary.

Both people with CDIs appeared to be in the beginning stages of SARS-CoV-2 infections, with early COVID-19 symptoms that resolved shortly after their FMTs.

“Our main conclusion from these cases,” say the study authors, “is that FMT appears safe and of comparable efficacy in treating recurrent CDI in patients with coexisting COVID-19. A further, more speculative question is as to whether FMT may impact the clinical course of COVID-19.”

The results of the study now appear in the journal Gut.

There is reason to connect the participants’ FMTs to the termination of COVID-19 symptoms. As the study authors write:

“Recent publications demonstrate that SARS-CoV-2 may undergo prolonged shedding in stool, and that gut microbiome perturbations associate with COVID-19 severity.”

C. diff is a difficult-to-treat bacterial infection. It causes nausea, fever, stomach pain, and diarrhea, and it can be life threatening without treatment. The Centers for Disease Control and Prevention (CDC) report that there were 12,800 deaths attributable to C. diff in the United States in 2017.

C. diff often occurs in people who require long-term antibiotic treatment. Antibiotics kill beneficial bacteria in the gut microbiome, setting the stage for unhealthy bacteria such as C. diff. People aged 65 years or older are also at increased risk of CDIs.

To reintroduce healthy bacteria into a compromised microbiome, doctors may implant stool from a healthy donor.

There are several ways in which a doctor may perform an FMT. These include inserting healthy stool directly into the colon during a colonoscopy, through a nasogastric tube, in an enema, or in the form of a swallowed capsule.

One of the cases described in the study involved an 80-year-old person with recurrent CDIs. They also had pneumonia and sepsis, which is a dangerous overreaction of the immune system in response to an infection.

A positive swab test revealed that the individual also had COVID-19 symptoms, including fever. They received treatment with remdesivir and convalescent plasma.

Two days after receiving an FMT, the person’s pneumonia appeared to have stabilized, and their COVID-19-related fever went away.

The second case involved a 19-year-old person with recurrent CDIs who was receiving treatment with immunosuppressant drugs and antibiotics for ulcerative colitis.

Fifteen hours after receiving an FMT, they developed COVID-19 symptoms, and a swab test confirmed that they did have the disease.

Other than two brief periods of fever, this person’s COVID-19 symptoms resolved without further treatment.

Both participants tested negative for SARS-CoV-2 when they were admitted for treatment. The transplanted stool also tested negative for SARS-CoV-2 before the FMT procedure.

The authors of the study note that both people experienced only mild symptoms, even though they were at risk of severe COVID-19. They write that “one possible explanation [could be] that [the] stool transplant mitigated more adverse outcomes, potentially through impacting microbiome-immune interactions.”

“Our findings,” write the researchers, “provide early evidence regarding the use of FMT in recurrent CDI in [people] with COVID-19. Furthermore, these data let us speculate that gut microbiome manipulation may merit further exploration as an immunomodulatory strategy in COVID-19.”

Next up for the researchers are clinical trials that will add FMTs to standard COVID-19 treatment in the hopes that a similar dramatic resolution of the disease’s symptoms will occur.

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