Daily Dose: Treating the Gut Microbiome Shortens Long COVID

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Patient Care brings primary care clinicians a lot of medical news every day—it’s easy to miss an important study. The Daily Dose provides a concise summary of one of the website's leading stories you may not have seen.

Last week, we reported on findings from a study published in the journal The Lancet Infectious Diseases that assessed a symbiotic preparation (SIM01) for the alleviation of post-acute COVID-19 syndrome (PACS) symptoms.

The study

Researchers evaluated a preparation that included 3 strains of bacteria — Bifidobacterium adolescentis, Bifidobacterium bifidum and Bifidobacterium longum — and 3 compounds that encourage the growth of healthful bacteria: galacto-oligosaccharides, xylo-oligosaccharides and resistant dextrin. The study subjects had had at least 1 of 14 long COVID symptoms for 4 weeks or more after a confirmed infection with SARS-CoV-2 by either a PCR test or a rapid antigen test.

Between June 2021 and August 2022, the researchers randomly assigned 463 adults (mean age 49 years, men and women equally represented) to take either a placebo (vitamin C) twice daily or the bacteria-prebiotic preparation. The primary end point was the alleviation of PASC symptoms by 6 months, defined as a reduction in the severity of symptoms leading to an improvement in activities of daily living. The symptoms were measured by responses to the PACSQ-14, a questionnaire commonly used in long COVID symptom research. After participant withdrawals and loss to follow-up, there were 204 individuals in the treatment group and 199 in the placebo group.

Findings

Results showed greater improvement among those in the treatment group vs those receiving placebo on all 14 long COVID symptoms.

The researchers also analyzed fecal samples and found greater diversity of bacteria diversity in the treatment group than in the placebo group. Their measurements also showed greater numbers of certain species (Bifidobacterium pseudocatenulatum and B. longum) and fewer of others (Klebsiella pneumoniae, Klebsiella variicola and Parabacteroides merdae). They also found association between the decreases in some symptoms with the bacteria; for example, B. adolescentis was positively associated with alleviation in fatigue.

Authors' comment

"Treatment with SIM01 alleviates multiple symptoms of PACS. Our findings have implications on the management of PACS through gut microbiome modulation. Further studies are warranted to explore the beneficial effects of SIM01 in other chronic or post-infection conditions."

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