Longitudinal Fecal Microbiota Profiles in a Cohort of Non-Hospitalized Adolescents and Young Adults with COVID-19: Associations with SARS-CoV-2 Status and Long-Term Fatigue

Adolescents most often experience mild acute COVID-19 but may still face fatigue and persistent symptoms such as post-COVID-19 condition (PCC) and post-infective fatigue syndrome (PIFS). We explored the fecal microbiota in a prospective controlled cohort of 136 non-hospitalized SARS-CoV-2-positive and 32 SARS-CoV-2-negative controls aged 12–25 years. With a targeted qPCR approach, the quantities of 100 fecal bacterial taxa were measured at baseline (early convalescent stage) and after six months. Results: Faecalibacterium prausnitzii M21.2 and Gemmiger formicilis (both p<0.001) were enriched in the SARS-CoV-2-positive participants compared to controls at baseline. Lower baseline abundance of Faecalibacterium prausnitzii M21/2 (p=0.013) and higher abundance of Clostridium spiroforme (p=0.006), Sutterella wadsworthensis (p<0.001) and Streptococcus thermophilus (p=0.039) were associated with six-month fatigue. Sutterella wadsworthensis and Streptococcus thermophilus enrichment was additionally associated with PCC in the SARS-CoV-2-positive group (p<0.001 and 0.042 respectively). Conclusions: In mild SARS-CoV-2 infection in adolescents and young adults, beneficial Faecalibacterium prausnitzii M21/2 and Gemmiger formicilis were enriched compared to SARS-CoV-2 negative controls. Additionally, both known (Faecalibacterium prausnitzii, Streptococcus thermophilus) and new (Clostridium spiroforme, Sutterella wadsworthensis) bacteria were associated with persistent symptoms in the COVID-19 infected group, warranting further exploration of the role of these bacteria in COVID-19 disease and PCC pathophysiology.