In the early stages of the pandemic, a considerable number of Americans encountered SARS-CoV-2, the virus responsible for COVID-19. However, due to testing limitations at the time, numerous cases went undiagnosed. Subsequently, a significant portion of these individuals experienced symptoms resembling those of long COVID, a condition characterised by symptoms persisting beyond six weeks.
A recent study delving into this subject examined a subset of these individuals, revealing that 41% displayed signs of past exposure to SARS-CoV-2. These intriguing findings were published in the prestigious journal Neurology Neuroimmunology & Neuroinflammation, an official publication of the American Academy of Neurology.
Dr. Igor J. Koralnik, a respected figure in the field and a member of the American Academy of Neurology, commented on the implications of these discoveries. He highlighted the predicament faced by those individuals who are undergoing similar symptoms but lack a positive COVID test result. “Most long COVID clinics are exclusive to patients with confirmed positive tests, leaving a significant group without specialised care and excluding them from vital research on the topic,” he stated. Dr. Koralnik went on to emphasise the importance of equitable access to care and participation in research studies for all individuals experiencing post-viral syndrome.
In the study, a cohort of 29 participants with post-viral syndrome and neurological symptoms like memory issues, headaches, and fatigue were meticulously examined. Interestingly, none of these individuals had tested positive for COVID-19. This group was compared to another cohort of 32 individuals with confirmed long COVID and a positive test result, as well as 18 individuals with neither the aforementioned symptoms nor exposure to the virus.
Intriguingly, the researchers tested these participants for antibodies related to two specific proteins that signal an immune response to a previous COVID infection—nucleocapsid protein and spike protein. Of the 29 individuals with post-viral syndrome, 41% demonstrated immune responses consistent with prior exposure to the virus, mirroring the responses observed in the long COVID group. Furthermore, three-quarters of this subset exhibited responses against the nucleocapsid protein, while half displayed responses against the spike protein.
Apart from similar immune responses, this group also exhibited comparable symptoms to the long COVID cohort and demonstrated analogous results in cognitive assessments.
Dr. Koralnik raised a pertinent issue concerning the treatment of long COVID cases. He noted that approximately 70% of post-COVID clinics in the United States do not admit individuals displaying long COVID symptoms without a confirmed positive test result. Highlighting the significance of their findings, he suggested that a substantial number of people—around four million—experiencing post-viral syndrome akin to long COVID might indeed have detectable immune responses supporting a COVID-19 diagnosis. However, he emphasized that further research is necessary to validate these findings.
It’s important to note that this study has limitations, primarily the relatively small sample size of individuals with post-viral syndrome. Additionally, some participants might have shown positive COVID-19 immune responses if their blood samples were collected closer to the onset of symptoms.
In light of these findings, the medical community faces a growing imperative to reconsider diagnostic criteria and extend necessary care to those who, despite the lack of a confirmed positive test, exhibit persistent symptoms resembling long COVID.
Reference: “SARS-CoV-2–Specific Immune Responses in Patients With Postviral Syndrome After Suspected COVID-19” by Zachary S. Orban, Lavanya Visvabharathy, Gina S. Perez Giraldo, Millenia Jimenez and Igor J. Koralnik, 23 August 2023, Neurology: Neuroimmunology & Neuroinflammation.
