Recent studies have identified changes to a nerve that may explain why some people suffer from long COVID-19, while separate findings may point to a potential treatment option.
The vagus nerve may play a role in why some people suffer from long COVID-19, according to a small study set to be presented April 23-26 at the European Congress of Clinical Microbiology and Infectious Diseases.
Researchers from Spain performed a morphological and functional evaluation of the vagus nerve — which is responsible for a variety of functions including controlling heart rate, speech, the gag reflex, moving food through the intestines and sweating — via imaging and functional tests in a cohort of 348 long COVID-19 subjects. At least 228 participants had at least one symptom suggestive of vagus nerve dysfunction. The current evaluation was performed in the first 22 subjects with VND symptoms. The study is ongoing.
Researchers believe many of the symptoms connected to long COVID-19 could be linked to the effect of the virus on the vagus nerve.
"In this pilot evaluation, most long COVID subjects with vagus nerve dysfunction symptoms had a range of significant, clinically-relevant, structural and/or functional alterations in their vagus nerve, including nerve thickening, trouble swallowing and symptoms of impaired breathing," the authors wrote. "Our findings so far thus point at vagus nerve dysfunction as a central pathophysiological feature of long COVID."
A separate small study set to be presented at the American College of Cardiology's Cardiovascular Summit Feb. 16-19 found enhanced external counterpulsation therapy, or EECP, may be a treatment option for long COVID-19 patients.
The noninvasive treatment is typically used for coronary artery disease patients and involves the use of pneumatic cuffs placed on a patients calves, thighs and lower hip area. The cuffs, connected to an electrocardiograph machine, sequentially inflate and deflate, pushing blood throughout the heart and rest of the body.
The study involved 50 long COVID-19 patients — 30 with no history of coronary artery disease and 20 patients with the disease. The findings showed long COVID-19 symptoms such as fatigue, breathing difficulties and chest discomfort improved among both patient groups after 15-35 hours of EECP therapy.
"Emerging data shows that long COVID is a disease that impacts the health of vessels, also known as endothelial function. EECP is a disease-modifying, noninvasive therapy that has previously shown to improve endothelial function in controlled clinical trials," said Sachin Shah, PharmD, senior author on the study and chief scientific officer at Flow Therapy, a nationwide EECP provider. "We currently believe that this is the most plausible explanation for the benefits derived from EECP and the link to long COVID."
Both studies have yet to be peer reviewed.