In 2024, the sequalae of the acute phase of coronavirus disease-19 (COVID-19) infection, which include neurological symptoms and are commonly referred to as long COVID or post-acute sequelae of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (PASC), continue to be a substantial health concern; however, similar symptoms are observed in individuals with no previous COVID-19 infection. In this single-center, retrospective, descriptive case series study the authors aimed to identify key features that could assist medical professionals in diagnosing neurological PASC, particularly in cases where patients lack a confirmed history of previous infection. Data were obtained from patients who visited our outpatient clinic specializing in PASC between June 1, 2021, and May 31, 2023. Antibody test results were compared between patients with confirmed acute phase infection and those without. The authors also compared differences in demographic and clinical characteristics between patients with positive results during the acute phase of COVID-19 infection and positive anti-SARS-CoV-2 antibody tests (true-PASC), and those with neither (PASC-mimic).
Of 437 patients diagnosed with PASC according to World Health Organization criteria, 222 underwent COVID-19 antibody tests. Of these, 193 patients (86.9%) had a history of confirmed acute phase infection, whereas 29 (13.1%) did not. Of the former, 186 patients (96.4%) were seropositive for anti-nucleotide SARS-CoV-2 antibodies (true-PASC), whereas 19 of the latter tested seronegative for anti-nucleotide SARS-CoV-2 antibodies (PASC-mimic). There were no significant differences in symptom characteristics between true-PASC and PASC-mimic participants. The authors concluded emphasizing the difficulty to identify any clinical features to aid in diagnosing PASC without confirmation of acute COVID-19 infection. The findings indicate the existence of a "PASC-mimic" condition that should be acknowledged and excluded in future PASC-related research studies.
Ohira M, Osada T, Kimura H, Sano T, Takao M. Post-acute sequelae of SARS-CoV-2 mimic: An important neurological condition. J Neurol Sci. 2024 Oct 15;465:123199. doi: 10.1016/j.jns.2024.123199. Epub 2024 Aug 22. PMID: 39182422.