Vagus nerve stimulation for long COVID

In a recently published study research place* Preprint servers, researchers evaluated the effectiveness of transcutaneous auricular vagus nerve stimulation (taVNS) in the treatment of long-lasting coronavirus disease 2019 (COVID-19).

Study: A pilot randomized controlled trial of supervised home self-administered transcutaneous auricular vagus nerve stimulation (taVNS) for the treatment of long-lasting COVID symptoms. Photo credit: Axel_Kock/Shutterstock


While the various manifestations of COVID-19 have been extensively studied, research is still needed to understand the ongoing neuropsychiatric effects of the infection. These persistent symptoms are referred to as post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PASC) infection, or long COVID, and occur in patients even months after diagnosis of COVID-19.

About the study

In the present study, researchers evaluated the feasibility and tolerability of remotely monitored taVNS and its implications for the management of symptoms associated with long COVID.

The study involved 13 people, including eight women, with a history of SARS-CoV-2 infection. The study procedures such as outcome measurement, stimulation and vital monitoring were carried out virtually by the participants themselves in the present remotely monitored home study. Eligible participants were at least 18 years old, had laboratory-confirmed SARS-CoV-2 infection, were afebrile and reported the occurrence of at least one new neuropsychiatric symptom of depression, anxiety, anosmia, dizziness, senility, fatigue, headache, brain fog or irritability.

The team developed a hard-shell briefcase containing all the equipment relevant to the test. This included physiology monitoring and stimulation equipment, as well as telecommunications equipment needed to ensure remote monitoring. After the participants received the briefcase, they were asked to charge the electronic components contained in the briefcase. Participants then participated in a virtual orientation session where they were instructed on how to use the systems in the suitcase. After the orientation session, the team organized the first treatment visit. Participants were told they would be monitored virtually for the first three days of the study to ensure safety and compliance.

The team developed a set of findings that tracked improvements in heterogeneous symptoms. The primary results of the study assessed safety and feasibility, while the secondary results estimated symptom improvement for the nine long COVID symptoms above. Feasibility was assessed during the pre-stimulation orientation visit and the first six treatment sessions. In addition, safety and tolerability results were measured by assessing each participant’s real-time heart rate (h) during stimulation over the first six sessions.


Study results showed that during the initial pre-pace orientation phase, nearly 91% of participants required assistance using remote heart rate monitoring, while all users required assistance with the taVNS equipment. Participants were instructed to complete two taVNS sessions each day for four days, each lasting one hour. A compliance assessment analyzed the proportion of sessions completed as a percentage of the aggregate likely number of sessions and showed that the active and control groups maintained high levels of compliance over a 2-week randomized period.

Data extracted from the taVNS systems showed that the control group received 52.3 minutes per session of sham stimulation, while the active cohort received active stimulation for 55.8 minutes per session. In particular, the team noted two cases of mild skin irritation in the form of skin redness due to prolonged stimulation. On the other hand, taVNS systems did not lead to any adverse cardiac events. Heart rate observed in the first six taVNS sessions throughout the study period showed that all participants’ hours were within the safe and normal range for adults.

While participants did not show all nine symptoms associated with long COVID, the team observed that the overall percentage of symptoms could be used as a meta-indicator of the severity of long COVID. At baseline, 66% of the control group reported symptoms, while 46% of the active cohort reported symptoms.

After the blinded two-week phase, 68% of the control group showed no improvement in symptoms, while 31% of the active group reported a reduced number of symptoms. After four weeks of treatment, the active and control groups showed 38% of the nine long-term COVID-19 symptoms. Notably, the control group participants who were treated for only two weeks reported an increased number of symptoms, while the active participants who were treated for four weeks showed no worsening of symptoms.

Overall, the study results demonstrated the development of a fully remote, monitored, home-use taVNS system that was safe, highly compliant, and tolerable in the tested sample of long-duration COVID patients. Researchers believe further studies should be conducted on a larger cohort of long COVID patients.

*Important NOTE

Research Square publishes preliminary scientific reports that have not been peer-reviewed and therefore should not be relied upon as conclusive, guide clinical practice/health behavior or be treated as established information.

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