Ongoing research shows that electrical vagus nerve stimulators may alleviate some symptoms of long Covid. But are these expensive devices worth it?
Introduction
Can a complex and varied condition like long Covid be treated without medications? Social media sparks debate over the experimental treatment targeting the vagus nerve, which acts as the “highway for information” in the body by transmitting critical signals between the brain and various internal organs. A mild electrical shock to this long cranial nerve triggers a wave of self-regulatory responses associated with relaxation – and may provide health benefits beyond that.
Self-Regulatory Responses and Vagus Nerve Therapy
Researchers increasingly recognize that long Covid is as much a neurological disorder as it is a cardiovascular and respiratory one. Treatment studies have indicated that the neurological aspects of the condition, including some related to the vagus nerve, may be relevant. Early small trials of vagus nerve stimulation showed reductions in hallmark long Covid symptoms such as chronic fatigue, headaches, and irregular blood pressure. Another study found that devices used to deliver electrical stimulation through the skin are safe and easy to use at home – providing comfort, accessibility, and a lower risk of infection. Scientists are still investigating which symptoms this technique can reliably address, which patients might benefit, and how long the effects last. In any case, the vagus nerve’s influence throughout the body seems crucial for treating some of the overarching manifestations of long Covid.
Stress Reduction
The vagus nerve – a bundle of fibers that extends from the brain stem and spreads throughout the body – regulates involuntary background processes and organ functions. It is part of the parasympathetic nervous system, which takes over to calm the body after a stressful event. During this recovery phase, the heart rate returns to normal, the immune system relaxes its defenses, and the digestive system starts functioning again. The vagus nerve acts as an “off” switch for the fight-or-flight nervous system. This nerve is also activated during activities like yoga, meditation, and slow breathing, which typically leave practitioners feeling calm and relaxed.
The Power of Electrical Stimulation
Electrical stimulation harnesses the power of the vagus nerve for easy healing. Some individuals may be able to reactivate their dysfunctional vagus nerve through mental exercises, but most need external assistance. This includes many people living with long Covid, as they often suffer from severe tissue damage and low energy levels. “Telling someone who has suffered from long Covid for three years and has seen 500 doctors to do some mental exercises – that’s not going to be good,” says Ravindra Ganesh, a doctor at the Mayo Clinic, who is currently leading a clinical trial of vagus nerve stimulation to treat long Covid using electroCore devices.
The Connection Between the Vagus Nerve and Long Covid
Researchers believe that vagus nerve stimulation alleviates long Covid symptoms by enhancing sympathetic nervous system pathways. One sign of heightened sympathetic activity is the continued activity of the immune system, even after the primary infection has resolved. The vagus nerve mitigates these excessive defenses by reducing the production of cytokines, which are signaling chemicals that promote inflammation. In 2000, researchers discovered the anti-inflammatory role of the vagus nerve when they found that stimulation reduced lethal septic shock in rats exposed to bacterial toxins. Many scientists believe that reactivating the vagus nerve can also reset the immune system in individuals dealing with severe Covid or chronic symptoms.
Stimulation
The Vagus Nerve for Alleviating Long COVID Symptoms
Experimental studies so far have shown that vagus nerve stimulation works best to alleviate excessive fatigue resulting from long COVID. Researchers noted that some participants in these studies reported improvements – but observed that others did not notice any improvement. “There is no experience with any drug or anything I’ve done over the years that makes a patient feel better so that they no longer meet the criteria for chronic fatigue syndrome,” says Benjamin Natelson, a neurologist at Mount Sinai, who has conducted several clinical studies on vagus nerve stimulation to treat various health conditions, some of which used devices from electroCore and Parasym. (Natelson states that he has not received funding for the studies from these companies.)
Electrical Stimulation and Side Effects
Since the vagus nerve consists of many fibers, researchers cannot control the individual fibers that are activated to target any specific organ; multiple sympathetic nervous system pathways are activated simultaneously during stimulation. This may seem concerning, but researchers agree that there are not many negative side effects resulting from overstimulation of the sympathetic nervous system. If a device of this type is used correctly, the worst potential complications would likely be mild skin irritation from electric shocks or diarrhea from excessive gastrointestinal activity.
Vagus Nerve Electrical Stimulation and Long COVID Stimulation
There are still scientific gaps in vagus nerve therapy that need to be addressed, so doctors are hesitant to widely prescribe it for long COVID before the confirmatory trial is completed. Scientists are still working on the details of the treatment, including the best method for delivery. For example, the electroCore strategy relies on a series of gentle shocks using a handheld device that users can touch to either side of the neck for a few minutes each day. Stats, the company’s founder, says this is the most effective site for stimulation where the vagus nerve is thickest. Other researchers, including those at Parasym, argue that alleviating long COVID symptoms requires longer stimulation times. These scientists note that the tip of the vagus nerve branch ends in the folds of the ear. Wearing a clip similar to a headphone without using hands could be a relatively comfortable way to deliver an hour of electrical stimulation daily.
Price Shock
There is also one notable concern regarding vagus nerve stimulation: the price. For instance, the electroCore device is offered on a pay-per-use basis that can cost an individual more than $7,000 a year without any discounts. The Parasym stimulator is priced at €699 (about $770) as a one-time purchase and is only sold in Europe (although Natelson mentions that some people he treats in the U.S. have managed to buy the device using European addresses). U.S. regulatory agencies have approved the electroCore device and some other versions from different companies as well – but exclusively for non-COVID-related issues like migraines. People suffering from long COVID can only purchase these products if prescribed by their doctors for off-label use, and it is unlikely that insurance companies will cover the cost without specific approval for long COVID.
Beware of Unapproved Trials
Researchers caution against attempting to build a homemade device or purchase unproven versions online. Vagus nerve stimulation involves running electrical current near your heart or brain. “Let’s not play with that,” says Janice. Approved medical devices are calibrated to be safe, but an unapproved device with incorrect settings can lead to slow or stopped heart. In severe cases, manipulating the vagus nerve can lead to sudden death.
The Key
Balance
Like any treatment for long COVID, the key is balance according to the body’s limits. At the Mayo Clinic, Grash often sees patients who are eager to start a new treatment pushing their bodies to the max and ultimately crashing. “If you continue to push forward after exhausting your body’s reserves, you will not feel the benefits of the interventions regardless,” says Grash.
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