Poop transplants may have helped two patients with risk factors avoid severe COVID-19, a new case report suggests. But the study was only based on two patients and so the improvement could have occurred by chance or as a result of other treatments.
The two patients were recently hospitalized in Poland with a bacterial infection and were given fecal transplants as a treatment. Both patients later tested positive for COVID-19, but neither developed severe disease despite having underlying conditions. "One possible explanation" is that the poop transplant, which is given to boost the immune response, may have prevented the patients from becoming very sick, the authors wrote in the study.
The procedure, called fecal microbiota transplantation (FMT), involves transplanting the poop of a healthy person into the gut of a patient who has an intestinal condition, such as an infection with the bacterium Clostridium difficile (also called Clostridioides difficile or abbreviated as C. diff), Live Science previously reported. This "healthy" poop is thought to have a mix of healthy bacteria that can help the body fight off the harmful pathogens that are causing issues such as diarrhea or irritable bowel syndrome.
Poop transplants have been used to help boost the effects of immunotherapy for cancer patients, Live Science previously reported. This is not the first time that fecal transplants have been proposed or administered without issue in patients with both a bacterial infection and COVID-19, but scientists don't know whether transplants can treat or reduce the severity of COVID-19.
Both patients in this case study went to the hospital for a bacterial infection and didn't develop symptoms of COVID-19 until they had already been admitted and began the fecal transplant treatment for the bacterial infection.
The first patient in the case study was an 80-year-old man who was first treated at the hospital for pneumonia and sepsis, or blood poisoning. But the man also happened to be infected with C. diff, for which he underwent FMT.
After he begun FMT, he also tested positive for SARS-CoV-2 (the virus that causes COVID-19) and started treatment on convalescent plasma (blood that contains antibodies taken from recovered COVID-19 patients) and an antiviral medication known as remdesivir. Remdesivir can lead to improvements after an average of 10 days, and the benefits of convalescent plasma are "limited," the authors wrote.
But surprisingly, two days after he was given poop transplants, his symptoms of COVID-19 cleared up and his pneumonia did not get worse.
The second patient was a 19-year-old man who had a type of inflammatory bowel disease known as ulcerative colitis and was being treated with drugs that suppressed the immune system. He was admitted to the hospital after a recurrent infection with C. difficile. He was given a poop transplant and antibiotics to treat the bacterial infection.
About 15 hours later, he developed a fever and tested positive for SARS-CoV-2. Even though he was immunocompromised and wasn't given any treatment for COVID-19, he only developed mild symptoms.
"Our main conclusion from these cases is that FMT appears safe and of comparable efficacy in treating recurrent [Clostridioides difficile infection] in patients with coexisting COVID-19," the authors wrote. "A further more speculative question is as to whether FMT may impact the clinical course of COVID-19."
In other words, poop transplants may have helped to mitigate severe disease in these patients, both of whom had risk factors for developing severe COVID-19. Still, even people with risk factors usually don't develop severe COVID-19, so both these patients might have recovered by chance.
Still, this was a case report of only two patients, and it's difficult to tease apart the effects of the various treatments. The researchers are now planning to test the effects of poop transplants on COVID-19 patients in a formal clinical trial.
The findings were published July 6 in the journal Gut.
Originally published on Live Science.