London, Feb 14 (IANS): Long Covid symptoms could be linked to the effect of the virus on the vagus nerve -- one of the most important multi-functional nerves in the body, according to a study.
The vagus nerve extends from the brain down into the torso and into the heart, lungs and intestines, as well as several muscles, including those involved in swallowing.
The nerve is responsible for a wide variety of bodily functions, including controlling heart rate, speech, the gag reflex, transferring food from the mouth to the stomach, moving food through the intestines, sweating, and many others.
The study led by researchers from University Hospital Germans Trias i Pujol in Spain, said that SARS-CoV-2-mediated vagus nerve dysfunction (VND) could explain some long Covid symptoms, including dysphonia (persistent voice problems), dysphagia (difficulty in swallowing), dizziness, tachycardia (abnormally high heart rate), orthostatic hypotension (low blood pressure) and diarrhoea.
"Our findings so far point at vagus nerve dysfunction as a central pathophysiological feature of long Covid," said Dr Gemma Llados from the University hospital.
Long Covid is a potentially disabling syndrome affecting an estimated 10-15 per cent of subjects who survive Covid-19. The symptoms are likely to persist from weeks up to a year.
The team performed a pilot, extensive morphological and functional evaluation of the vagus nerve, using imaging and functional tests in a prospective observational cohort of 348 long Covid subjects with symptoms suggestive of VND.
About 66 per cent showed at least one symptom suggestive of VND, up to 14 months.
Further tests were carried out in the first 22 subjects with VND symptoms.
"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," Llados said.
The pilot study will be presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID 2022) to be held in Lisbon in April.