Long Covid may be caused by the virus damaging crucial vagus nerve, scientists claim
- Damage to the vagus nerve may be behind some long Covid symptoms
- Digestive issues and an elevated heart rate could be caused by changes in nerve
- Findings suggest vagus nerve dysfunction is a ‘central’ feature of long Covid
Some long Covid symptoms could be caused by the virus damaging a vital nerve, a study suggests.
Scientists believe inflammation to the vagus nerve could explain some of the broad and seemingly unrelated range of symptoms that can plague survivors months after beating the illness.
Long Covid, the umbrella term for symptoms ranging from neurological to digestive, heart and lung problems, has puzzled scientists throughout the pandemic.
The vagus nerve is the longest nerve in the body, connects vital organs including the brain, heart, lungs and intestines, and controls muscles used for swallowing. Experts describe it as the ‘motorway’ of the nervous system.
Scientists from a hospital in Spain conducted tests on 350 long Covid patients and quizzed them on their symptoms to determine whether the nerve was linked to the lingering health problems.
Results from their preliminary analysis, based on 20 patients, shows symptoms such as gastrointestinal problems and an elevated heart rate were linked with damage to the vagus nerve.
The researchers said their findings, not published in full or peer-reviewed, suggest structural changes to the vagus nerve are a ‘central’ feature of long Covid.
Spanish scientists said Covid-triggered inflammation to the nerve may be behind long-lasting symptoms including gastrointestinal problems and an elevated heart rate
What is Long Covid?
As of January 2, an estimated 1.33million people in the UK were estimated to have long Covid.
Long Covid is an informal term, used to describe ongoing symptoms following a Covid infection that go on longer than four weeks, according to the ONS.
A dizzying array of symptoms have been attributed to long Covid, including:
- extreme tiredness (fatigue)
- shortness of breath
- chest pain or tightness
- problems with memory and concentration (‘brain fog’)
- difficulty sleeping (insomnia)
- heart palpitations
- pins and needles
- joint pain
- depression and anxiety
- tinnitus, earaches
- feeling sick, diarrhoea, stomach aches, loss of appetite
- a high temperature, cough, headaches, sore throat, changes to sense of smell or taste
There is no cure for the condition though the NHS does recommend a number of treatments designed to help alleviate the symptoms.
Damage to the blood vessels caused by the coronavirus has also been heavily linked to long Covid.
Official estimates show around 1.3million Britons, 2.1 per cent of the population, have long Covid-like symptoms that last at least four weeks after infection.
But because the condition is hard to define and figures are based on self-reported symptoms, it is hard to know exactly how many people are affected by the condition.
Fatigueshortness of breath and loss of smell or taste are the most common ongoing symptoms.
To examine the role of the vagus nerve — roughly 3mm in diameter — in long Covid, medics at University Hospital Germans in Badalona recruited 348 sufferers.
Two-thirds of the group had symptoms similar to those who had damaged the nerve — which usually occurs through surgery, physical injury or a tumour.
These included diarrhoea, an elevated heart rate, dizziness, difficulty swallowing, voice problems and low blood pressure.
Further tests of 22 patients also showed that slightly more than a quarter had a thickened or inflamed vagus nerve.
Almost all of them, however, suffered symptoms relating to vagus nerve dysfunction, including diarrhoea, an elevated heart rate and dizziness.
Dr Gemma Lladós and Dr Lourdes Mateu, medics at hospital and authors of the study, said the results show most long Covid patients with symptoms of vagus nerve damage had changes in the structure or function of their nerve.
‘Our findings so far thus point at vagus nerve dysfunction as a central pathophysiological feature of long Covid,’ they added.
The findings were presented at the European Congress of Clinical Microbiology and Infectious Diseases.
Dr David Strain, a senior clinical lecturer at the University of Exeter Medical School who was not involved in the study, said it adds to growing evidence that at least some long Covid symptoms are ‘mediated through a direct impact on the nervous system’.
He said: ‘It is entirely possible that people susceptible to nerve damage are at the greatest risk of developing long Covid.
‘In this case this observation tells us little more than nerve damage is a result of Covid, this is greater in those with long Covid and the damage is easy to detect in a long, complex nerve.’
But Dr Strain noted that not all persistent symptoms post-infection will be linked with this nerve, so more investigation is needed into the triggers of brain fog and muscle aches.
He said drugs used to treat vagus nerve damage could be considered for long Covid.