IDDF2024-ABS-0299 Gut microbiota changes in relation to long-COVID-19 syndrome

Background The COVID-19 pandemic has posed a significant global public health crisis, with approximately 10-20% of people infected with SARS-CoV-2 developing Long COVID. Long COVID is characterized by the persistence of symptoms beyond 4 weeks or longer after SARS-CoV-2 infection. The symptoms include fatigue, shortness of breath, sleep difficulties, loss of appetite, gastrointestinal upset, and other illnesses. Long COVID can seriously affect daily functioning and quality of life. However, its etiology remains unclear. Studies have demonstrated a substantial correlation between the severity of COVID-19 and compositional changes in the gut microbiome. This systematic review aims to investigate the relationship between gut bacteria and the development of Long COVID. Methods The systematic literature search was performed based on the PRISMA guidelines along with relevant MeSH terms, ('gut' or 'microbiome') AND ('Long COVID' or 'post-acute COVID-19 syndrome') in three databases (PubMed, ProQuest and Scopus) until April 30, 2024. The titles and abstracts of all retrieved studies were evaluated using the inclusion and exclusion criteria. Studies involving gut microbiome and Long COVID were considered for inclusion. Exclusion criteria are mostly unrelated, duplicated, unavailable full texts, case reports and systematic review studies. Results Six studies were eligible for final qualitative analysis, with a total of 610 Long COVID patients recruited from March 2020 to October 2022. Research findings have shown that Long COVID patients have a significant decrease in the abundance of short-chain fatty acid-producing bacteria such as Firmicutes (Faecalibacterium prausnitzii, Roseburia intestinalis, Eubacterium hallii, Subdoligranulum, Ruminococcus), Actinobacteria (Bifidobacterium pseudocatenulatum, Bifidobacterium adolescentis), whilst an increase abundance of Pseudomonadota (klebsiella pneumoniae, klebsiella quasipneumoniae), Bacteroidetes (Bacteroidetes vulgatus, Bacteroidetes xylanisolvens, Prevotella), Firmicutes (Ruminococcus gnavus, Veillonella). Conclusions This outcome highlights the gut microbiome alterations associated with the development of Long COVID (IDDF2024-ABS-0299 Figure 1) that may contribute to the persistence of symptoms. The link between the gut microbiome and Long COVID suggests that interventions targeting microbiota modulation may alleviate Long COVID symptoms by restoring a healthy gut microbiome.