Our data suggest that SARS-CoV-2 induces vagus nerve inflammation followed by autonomic dysfunction which contributes to critical disease courses and might contribute to dysautonomia observed in long COVID.

Background: Postural orthostatic tachycardia syndrome (POTS) has been described early after the onset of the COVID-19 infection, but also orthostatic hypotension (OH). In the present study, we hypothesized that orthostatic intolerance decreases over time. Methods: In 29 long-haul COVID-19 (LHC) patients, a tilt test was performed, including measurements of cerebral blood flow (CBF) by extracranial Doppler. The time interval between the onset of infection and the tilt test varied between 3 and 28 months. Results: In the first 12 months after the infection, 71% of the LHC patients showed POTS and after 24 months none of them. In the first 12 months, 29% of patients had a normal heart rate and blood pressure response (normHRBP) and after 24 months 75% (distribution of POTS, OH, and a normHRBP over time: p < 0.0001). Linear regression showed that, over time, there was a decrease in the abnormal CBF during the tilt (p = 0.024) but remained abnormal. Conclusion: In LHC patients, hemodynamic abnormalities of a tilt test change over time. Patients studied early after the onset of the disease mainly exhibit POTS, but patients studied later in the time course mainly show a normHRBP or OH. In addition, the abnormal CBF reduction improves over time, but CBF remains abnormal.

These findings support the hypothesis that POTS may be an autoimmune, inflammatory and hyperadrenergic disorder.