A new study published in the European Respiratory Journal found that people with severe long COVID have different oral and pulmonary microbiomes than those with mild symptoms. CIDRAP has the news.

Additionally, the differences are linked to specific symptoms, which may lead scientists to a clearer picture of the condition and how to treat it.

771 adults were recruited and grouped by severity of ongoing health problems and symptom subgroups. Saliva and sputum samples were taken six months after release from the hospital. In the group with very severe long COVID symptoms, the oral microbiota was significantly less diverse than that in the group with mild symptoms. This group had the highest frequency of breathlessness, fatigue, impaired lung function, and reduced exercise capacity.

Impaired lung function and neurocognitive symptoms were linked to separate distinct oral microbiota profiles; GI symptoms were associated with a distinct sputum microbiota profile. There was also an overabundance of lactic acid bacteria in patients with ongoing symptoms.

The authors cautioned it isn’t clear whether the microbiota changes occurred before or after COVID-19 infection or whether the microbiome recovers over time.