Fecal Microbiota Transplantation for Sleep Disturbance in Post-acute COVID-19 Syndrome

Background & Aims Post-acute COVID-19 syndrome (PACS) is associated with sleep disturbance but treatment options are limited. The aetiology of PACS may be secondary to alterations in the gut microbiome. Here, we report the efficacy of faecal microbiota transplantation (FMT) in alleviating post-COVID insomnia symptoms in a non-randomised, open-label prospective interventional study. Methods Between September 22, 2022 and May 22, 2023, we recruited 60 PACS patients with insomnia defined as Insomnia Severity Index (ISI) ≥ 8 and assigned them to the FMT group (FMT at weeks 0, 2, 4 and 8; n=30) or the control group (n=30). The primary outcome was clinical remission defined by an ISI of less than eight at 12 weeks. Secondary outcomes included changes in the Pittsburgh Sleep Quality Index (PSQI), Generalised Anxiety Disorder-7 scale (GAD-7), Epworth Sleepiness Scale (ESS), Multidimensional Fatigue Inventory (MFI), blood cortisol and melatonin, and gut microbiome analysis on metagenomic sequencing. Results At week 12, more patients in the FMT than the control group had insomnia remission (37.9% vs 10.0%; p=0.018). The FMT group showed a decrease in ISI score (p<0.0001), PSQI (p<0.0001), GAD-7 (p=0.0019), ESS (p=0.0057) and blood cortisol concentration (p=0.035) from baseline to week 12, but there was no significant change in the control group. There was enrichment of bacteria such as Gemmiger formicilis and depletion of microbial pathways producing menaquinol derivatives after FMT. Gut microbiome profile resembled that of the donor in FMT responders but not in non-responders at week 12. There was no serious adverse event. Conclusion This pilot study showed that FMT could be effective and safe in alleviating post-COVID insomnia and further clinical trials are warranted. ClinicalTrials.gov identifier: NCT05556733.