From January 16, 2014 and November 14, 2018, patient-level outcomes from recipients of FMT was consecutively collected from 681 health care facilities across 50 US states and 7 countries. The cohort consisted of complete, consecutively collected patient reports (n = 5344).

Overall, the safety profile was favorable among a patient population that is medically complex with poor clinical outcomes. Among the cohort, 194 patients (3.6%) were reported to have experienced 1 or more SAEs. SAEs were more common among patients with severe or severe-complicated CDI (n = 94 [48.5%]). Among the SAEs, 6 reported events (0.1%) were possibly related to FMT—all among patients who were severely immunocompromised. This included 2 patients with fever as well as 1 with abdominal pain in a breast cancer patient with severe-complicated CDI. In addition, there were 2 patients with systemic inflammatory response syndrome—1 post-cardiac transplantation and 1 post-renal transplantation. There was 1 reported case of an inflammatory bowel disease (IBD) flare in a patient with a background of uncontrolled ulcerative colitis on biologics and immunomodulators. No reported SAEs were determined to be definitely related to FMT. Importantly, there were no reported cases of sepsis or infectious disease transmission related to FMT, including multi-drug–resistant organism-related infections.

A search for studies of FMT in patients with CDI was performed with the rate of serious adverse events (SAEs) related to FMT evaluated as the primary outcome. Secondary outcomes included SAEs unrelated to FMT and minor adverse events associated with FMT.

Pooled analysis of 5099 patients receiving 5551 FMTs showed that SAEs related to FMT developed in less than 1% of patients. The pooled rate of SAEs not related to FMT was higher at 2.9%. The pooled rate of minor adverse events also showed infrequent self-limited gastrointestinal and systemic discomfort.

This meta-analysis supports FMT as a safe option for treating recurrent CDI. Future randomized trials are needed to improve our current understanding of FMT safety and further examine the improvements in the quality of life of patients treated with FMT compared to standard therapy of antibiotics.

This review by Park and Seo concludes that "FMT is generally considered safe, and a recent study suggested that it is well-tolerated in high-risk patients. Rigorous donor screening and testing should be mandated to minimize the risk of FMT, especially during the COVID-19 pandemic."

The FMT National Registry was designed to assess FMT methods and both safety and effectiveness outcomes from North American FMT providers.

Results: Of the first 259 participants enrolled at 20 sites, 222 had completed short-term follow-up at 1 month and 123 had follow-up to 6 months; 171 (66%) were female. All FMTs were done for CDI and 249 (96%) used an unknown donor (eg, stool bank). One-month cure occurred in 200 patients (90%); of these, 197 (98%) received only 1 FMT. Among 112 patients with initial cure who were followed to 6 months, 4 (4%) had CDI recurrence. Severe symptoms reported within 1-month of FMT included diarrhea (n = 5 [2%]) and abdominal pain (n = 4 [2%]); 3 patients (1%) had hospitalizations possibly related to FMT. At 6 months, new diagnoses of irritable bowel syndrome were made in 2 patients (1%) and inflammatory bowel disease in 2 patients (1%).

Conclusions: This prospective real-world study demonstrated high effectiveness of FMT for CDI with a good safety profile. Assessment of new conditions at long-term follow-up is planned as this registry grows and will be important for determining the full safety profile of FMT.

Aim: To evaluate the safety of FMT by summarizing the overall reported Adverse Events (AEs) over a 20-year period.

Results: Based on the inclusion criteria, 129 studies, which included 4241 patients (5688 FMT courses), were analyzed.  Overall, FMT-related AEs were observed in 19% of FMT procedures. The most frequently reported FMT-related AEs were diarrhea (10%) and abdominal discomfort/pain/cramping (7%). FMT-related serious adverse events (SAEs), including infections and deaths, have been reported in 1.4% of patients who underwent FMT (0.99% microbiota-related SAEs).  Importantly, all reported FMT-related SAEs were in patients with mucosal barrier injury.

Conclusion: Most FMT-related AEs were mild or moderate and self-limiting. Although FMT appears to be highly safe, its methodology should be improved to reduce both delivery-related AEs and, microbiota-related AEs.