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Gut dysbiosis is often linked to persistent multi-system symptoms after SARS-CoV-2 infections or post-acute COVID-19 syndrome.

In data presented during the 2023 Digestive Disease Week (DDW) in Chicago as a late-breaking abstract, a team, led by Raphaela Iris Lau, Department of Medicine and Therapeutics, Faculty of Medicine, The Chinese University of Hong Kong, assessed the effects of gut microbiome modulation on the alleviation of post-acute COVID-19 syndrome.

The Study

In the single-center, triple-blind, randomized, placebo-controlled study, the investigators looked at patients with COVID-19 who recovered who reported persistent post-acute COVID-19 symptoms.

Each patient was randomized to either the novel oral microbiome immunity formula (SIM01, symbiotic) group or the oral placebo group for 6 months.

The investigators sought primary outcomes of the alleviation of post-acute COVID-19 syndrome symptoms by month 6 compared to baseline. This was assessed by a structured 14-item symptom questionnaire. They also looked at secondary outcomes of the reduction of gastrointestinal symptoms severity, evaluated by a self-report scale from 1-4.

The team used Chi-squared tests to evaluate the association between intervention and symptom alleviation and used Wilcoxon signed-rank tests to compare the changes in severity scores between baseline and month 6.

The Bonferroni correction was applied to adjust for multiple comparisons of symptoms.

Gut Microbiota

The study included 463 patients with a mean age of 49.4 years. Each was randomization at a duration of 4 months following a COVID-19 diagnosis and each participant had at least 1 of the 14 common symptoms of post-acute COVID-19 syndrome at randomization and were included in the intention-to-treat analysis.

The results show a high proportion of patients in the SIM01 group had improvements in various symptoms, including fatigue (62.8% vs 42.6%, P <0.001), memory loss (42.0% vs 26.9%, P =0.002), difficulty in concentration (62.3% vs 38.5%, P <0.001), digestive problems (70.2% vs 54.1%, P = 0.001), and general unwellness (77.3% vs 59.0%, P = 0.001) by 6 months compared with the placebo group, after adjusting for multiple comparisons.

Specifically in the 134 participants who reported digestive problem improvements followed by SIM01 treatment, there was a significant reduction in severity score for 7 of the 8 gastrointestinal symptoms assessed, including diarrhea (P <0.001), constipation (P <0.001), abdominal pain (P = 0.003), epigastric pain (P <0.001), bloating (P <0.001), vomiting (P = 0.005), and acid reflux (P <0.001), following Bonferroni correction.

“This is the first randomized controlled trial showing that modulation of gut microbiome with a novel oral microbiome formula (SIM01) alleviates gastrointestinal and neuropsychiatric symptoms of PACS,” the authors wrote.