Revealing the Hidden Impact of Long Covid: How Microbiomes Might Hold the Key

Recent research sheds light on the microbiome's role in long Covid, revealing significant differences in the bacteria present in the mouths and lungs of affected individuals. This study, published in the European Respiratory Journal, highlights how these microbiome changes correlate with various symptoms, including respiratory, cognitive, and digestive issues. By analyzing samples from 771 patients, researchers aim to uncover the underlying causes of long Covid and explore new treatment possibilities. The findings suggest that understanding the microbiome could be crucial in addressing the ongoing health challenges faced by millions worldwide.

By Narendra Chaudhary Oct 12, 2026, 16:16 IST

Understanding Long Covid Through Microbiome Research

New Delhi: Research indicates that individuals suffering from long Covid, characterized by lingering symptoms post-Covid-19 recovery, exhibit notable variations in the bacterial communities residing in their mouths and lungs.

These variations in the lung microbiome correlate with respiratory issues, as well as cognitive and digestive complications commonly associated with long Covid, according to the study.

Published in the European Respiratory Journal, these findings may enhance our understanding of why certain individuals develop long Covid and suggest potential treatment avenues.

Lead researcher Daniela Alferes de Lima Headley from the University of Dundee, UK, stated, "Previous studies have highlighted alterations in the gut microbiome related to long Covid, but given that Covid primarily affects the lungs, it is logical to investigate changes in the lung microbiome as well."

"With millions globally still grappling with long Covid and its origins remaining unclear, it is crucial to explore how the microbiome, vital for overall health, may play a role in this condition," she added.

The study involved 771 Covid-19 patients treated across 38 UK hospitals from February 2020 to March 2021.

Participants were categorized into four groups based on the severity of their symptoms five months post-hospital discharge, ranging from 'very severe' with significant physical, mental, and cognitive challenges to 'mild' with minimal symptoms and good recovery.

Six months after discharge, saliva samples were collected from patients' mouths and sputum from their lungs. DNA sequencing was employed to identify the microbial presence.

By analyzing the diversity and quantity of microbes and correlating them with patient symptoms, researchers discovered that those with severe long Covid exhibited significant differences in their oral and lung microbiomes compared to those without severe symptoms.

The study also identified variations associated with specific symptoms, such as diminished lung function, where the lungs struggle to hold air or facilitate airflow.

Additionally, differences in the microbiomes of the mouth and lungs were noted among individuals experiencing various neurocognitive symptoms, including 'brain fog', memory issues, and gut-related symptoms like pain, nausea, diarrhea, and appetite loss.

Among the notable changes linked to long Covid symptoms was an excess of lactic acid-producing bacteria, which corresponded with inflammatory markers found in patients' blood samples.

James Chalmers, chair of respiratory research at the University of Dundee, remarked, "Patients exhibiting the most severe symptoms five to six months after their Covid infection showed significant microbiome alterations in their mouths and lungs."

"Moreover, the changes in the airway microbiome were associated not only with lung issues but also with symptoms like brain fog and gastrointestinal problems, indicating that the lung microbiome may influence overall health more broadly," he concluded.