Long-haul COVID is a multi-system disease that affects almost all organ systems. One of the major systems it effects is the gut microbiome. It’s sequela causes impairment in the gut-brain signaling and metabolic regulation. There are now several studies showing that probiotics, consisting of beneficial bacteria such as Lactobacillus and Bifidobacterium species might enhance gut health, modulate inflammation and improve the immune system. A randomized control trial in Hong King found that a synbiotic drug called SIM01 relieved multiple symptoms of long haul COVID. This synbiotic contained strains of anaerobic Bifidobacterium bacteria and soluble fibers (probiotics) to alter the microbiome and possibly modify immune response.
The study took place from June 2021-August 2022 and researchers from the Chinese University of Hong Kong randomly assigned 463 adult long COVID patients in their hospital. Half received SIM01 (10 billion colony-forming units in sachets twice daily) or a Vitamin C placebo by mouth twice a day for 6 months. The average time between infection and assignment was 4 months. Baseline assessment of symptoms was taken before the study and included quality of life and physical activity level. At 6 months participants received a 14- item symptom questionnaire and collected blood and fecal samples.
Nearly 1/3 of patients had been hospitalized during their infections. At 6 months a significantly higher proportion of patients in the SIM01 group reported an improvement of fatigue, memory loss, difficulty concentrating, GI upset and general unwellness than placebo. There were main differences in the microbiome of both groups. The researcher wrote: “decreased abundance of short-chain fatty acid producing bacteria in the gut of patients with COVID-19 might represent one of the crucial mechanisms contributing to the gut-lung interaction and thereby disease severity in COVID-19”. They also reported the gut microbiome was more diverse, including more short-chain acid-producing bacteria and fewer genes related to antibiotic resistance, at 6 months than at baseline in SIM01 patients but not the placebo group.
From an extensive body of research in people effected by long-haul COVID, there appears to be multiple potential pathways including microbiome dysbiosis. Even though this product in the study SIM01, is not commercially available, we may be able to simulate these species of bacteria through diet and supplementation. Prebiotic fiber refers to a fiber thats a food source for the microorganisms in your gut.
The incidence of post acute COVID-19 syndrome or long-haul is estimated to be 10-30% and at least 65 million individuals worldwide. This study has shown findings that have implications on managing long-haul COVID through gut microbiome modulation. Further studies are needed and are in progress in identifying the pathogenesis of post acute COVID syndrome and effective treatments for this complex condition.
References: Ziyad-Al Aly, Topol, E. Solving the puzzle of long COVID: Long COVID provides an opportunity to understand how acute infections cause chronic disease. Science Feb 22 2024, Vol 383, issue 6685.
Sheikh, Z. Types of Fiber: Soluble and Insoluble fiber: Diet and weight management. WebMD January 17, 2024.
Lau, Raphaela, et al. A synbiotic preparation (SIM01) for post-acute COVID-19 syndrome in Hong Kong (RECOVERY): a randomized, double-blind, placebo-controlled trial. Published December 07, 2023. The Lancet-Infectious Diseases. Vol 24, issue 3, P. 256-265, March 2024.