Observational Study Links Very Severe Long COVID to Distinct Lung and Oral Microbiome Patterns
An observational cohort of 771 UK patients demonstrates microbiome alterations in the airways and mouth that track with multi-system long-COVID severity. The findings generate mechanistic hypotheses but require longitudinal sampling and interventional trials to test causality and therapeutic potential. Evidence remains associative pending randomized studies of microbiome-modifying interventions.
The study collected sputum and saliva samples from hospitalized COVID survivors between February 2020 and March 2021, stratified them into four symptom-severity clusters at five months, and performed 16S rRNA sequencing six months after discharge. Very-severe cases displayed lower alpha diversity and higher relative abundance of lactate producers, coinciding with elevated blood inflammatory markers; these shifts also tracked with objective measures of impaired gas transfer and self-reported brain fog or gut symptoms. Because the design captured only cross-sectional associations after infection, it cannot distinguish whether microbiome differences predated COVID, arose during acute illness, or persisted as a consequence of hospitalization or treatment.
Chalmers et al.: In a planned 24-month PHOSP-COVID extension, at least 40% of very-severe participants will exhibit partial microbiome normalization accompanied by a 20% or greater reduction in symptom scores.
Sources (3)
- [1]Primary Source(https://erj.ersjournals.com/content/early/2024/10/03/13993003.00895-2024)
- [2]Supporting Source(https://www.phosp.org/)
- [3]Supporting Source(https://www.nejm.org/doi/full/10.1056/NEJMoa2306697)