Neurological Complications Associated With COVID-19 Compared to Other Viral Infections: A Systematic Review of Current Evidence.

Neurological complications have become one of the most concerning features of COVID-19, yet clinicians still lack a clear comparison between these findings and what is seen in other viral infections. Understanding where SARS-CoV-2 fits, whether it behaves like influenza and dengue or follows an entirely different pattern, is essential for diagnosis, management, and planning long-term care. We conducted a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO: CRD420251064831). Searches across PubMed, Scopus, and Web of Science (2000-2025) identified 24 eligible studies, including observational cohorts, clinical trials, case series, autopsy work, and national surveillance data. Because of the wide variation in study design and reporting, a narrative synthesis was used. Across the 24 studies, COVID-19 exhibited the widest and most severe spectrum of neurological involvement. Reported central nervous system complications included ischemic stroke, encephalopathy or encephalitis, seizures, and extensive microglial and white-matter injury in fatal cases. Peripheral complications were also prominent, such as anosmia, demyelinating neuropathies, Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy, functional movement disorders, and persistent abnormalities on nerve conduction testing long after recovery. In contrast, neurological complications from influenza were less frequent and mostly involved encephalitis/encephalopathy, seizures, meningitis, GBS, or myelitis, with generally low mortality. Dengue virus has been associated with a spectrum of direct neurotropic effects and immune-mediated syndromes, including encephalitis, GBS, myelitis, brachial neuritis, and myositis. Most patients recovered, and mortality remained low. Compared with influenza and dengue, COVID-19 stands out for both the breadth and severity of its neurological manifestations, as well as the persistence of symptoms in many survivors. These findings highlight the need for early neurological evaluation in COVID-19, structured follow-up after recovery, and more consistent research methods to allow better comparisons across viral infections.