Neurologic Impacts of Long COVID, an Autoimmune Syndrome: Igor Koralnik, MD

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"We believe Long COVID is a new autoimmune syndrome, which occurs when the immune system becomes confused by the virus and begins to attack the body as though something abnormal is present."

Long COVID, also referred to as post-acute sequelae of SARS-CoV-2 infection (PASC), frequently presents with neurological symptoms collectively known as Neuro-PASC. A recent study published in Brain Communications analyzed the impact of prior vaccination on Neuro-PASC symptoms in 200 post-hospitalization (PNP) and 1100 nonhospitalized (NNP) patients treated at a neuro-COVID clinic between May 2020 and January 2023.^1,2 While vaccination was effective in reducing the severity of acute COVID-19, it did not significantly influence the neurologic symptom burden associated with Long COVID. Common symptoms across both patient groups included brain fog, headache, and dizziness, with only minor differences observed between cases of prevaccination and breakthrough infections.

The study also revealed significant quality-of-life impairments in both PNP and NNP cohorts, particularly in cognitive functioning, fatigue, sleep, and mental health domains. Cognitive testing deficits were similar regardless of vaccination status. Patients with breakthrough infections exhibited a higher prevalence of pre-existing conditions such as anxiety, depression, and organ-specific comorbidities, potentially affecting symptom severity and management. These results highlight that while vaccination does not alleviate neurologic symptoms of Long COVID, the influence of evolving viral variants and individual risk factors underscores the need for further research and tailored care approaches.

In a recent interview with NeurologyLive^®, Igor Koralnik, MD, chief of neuroinfectious diseases and global neurology at Northwestern Medicine, emphasized the importance of identifying specific biomarkers to better understand the metabolic and mitochondrial changes underlying Long COVID symptoms. In addition, Koralnik highlighted that mitochondrial dysfunction likely contributes to hallmark symptoms such as fatigue, post-exertional malaise, and cognitive deficits. He also underscored the critical role of interdisciplinary subspecialty clinics in providing comprehensive care for patients with Long COVID, addressing the diverse and complex manifestations of the condition through a coordinated, patient-centered approach.

REFERENCES
1. Mukherjee S, Singer T, Venkatesh A, et al. Vaccination prior to SARS-CoV-2 infection does not affect the neurologic manifestations of long COVID. Brain Commun. 2025;7(1):fcae448. Published 2025 Jan 7. doi:10.1093/braincomms/fcae448
2. New research finds COVID-19 vaccination prior to infection does not affect the neurological symptoms of long COVID. News Release. Northwestern Medicine. Published January 13, 2024. Accessed January 13, 2024. https://news.nm.org/new-research-finds-covid-19-vaccination-prior-to-infection-does-not-affect-the-neurological-symptoms-of-long-covid

Editor’s Note: Koralnik has disclosed that he has engaged in activities such as speaking, advising, consulting, or providing educational programs for the following companies or other entities: American Society for Clinical Investigation, Inc.; Antisense Therapeutics Limited; Teladoc, Inc. He also has the right to receive payments or may receive future financial benefits for inventions or discoveries related to the following companies or other entities: UpToDate, Inc.