By: Meric Berrendaffan, Human Biology, Health, and Society ‘26
As COVID-19 seemingly fades from the news and most people’s worries, it is baffling to think that there is still a plethora of missing information about the constantly evolving virus that took over the world four years ago. One of the most important missing pieces is the reason why the virus is actually still on so many peoples’ minds: the emerging phenomenon of “Long-COVID.” The Centers for Disease Control and Prevention (CDC) defines “Long-COVID” as, “signs, symptoms, and conditions that continue to develop after acute COVID-19 infection” (1). According to the Mayo Clinic, symptoms of Long-COVID can feature many of the same symptoms that are common during the initial infection, including fatigue, fever, muscle pains, and shortness of breath, as well as several other manifestations that do not usually occur during the initial infection, including changes in the menstrual cycle, blood clots, and, most interestingly, neurological and psychiatric symptoms (2).
Neurological and psychiatric presentations of Long-COVID are some of the least researched and most overlooked signs of the condition and can include muscle weakness and twitches, insomnia, paresthesia, trouble focusing, and even depression and anxiety. The true prevalence and causality of these symptoms being related to COVID-19 is incredibly hard to pinpoint. According to a University of Oxford study of 236,379 people infected with COVID-19 between January and December of 2020, the incidence of neurological and psychiatric disorder diagnoses after COVID-19 infection was 34% (3). Some of the possible reasons why many of these symptoms are so difficult to definitively attribute to Long-COVID is due to the fact that each of these symptoms can be caused by other conditions, can occur on their own, or can be ignored until they become prolonged or severe enough. Additionally, neurological and psychiatric symptoms and disorders, aside from in the case of herpes simplex virus Type I and viral meningitis, are not normally attributed to viral infections. While the coronavirus is truly unique, viral infections are already known for being a silent culprit of neurological disorders, but not the way that people would commonly think. To take a look at the connection, let’s go back just over a century.
The latest pandemic before the COVID-19 pandemic was the Spanish flu outbreak between 1918 and 1919 that infected over 500 million people worldwide. It wasn’t until the 1960s when doctors discovered that people who were infected with the Spanish flu anytime between infancy and young adulthood were “two to three times more likely to develop Parkinson’s disease” (4). Parkinson’s disease is an incurable degenerative neurological disorder that causes deterioration of the brain and is just one of the neurological disorders that has been attributed to prior viral infection (5).
Since the Spanish flu pandemic, researchers have found several other viruses, including strains of influenza, including Human Immunodeficiency Virus (HIV), Epstein-Barr virus, Hepatitis B, and Respiratory Syncytial Virus (RSV), that have been linked to increased risk of Parkinson’s Disease and other debilitating neurological disorders such as, Amyotrophic Lateral Sclerosis, Guillain-Barre Syndrome, Alzheimer’s Disease, and Multiple Sclerosis (6). Unfortunately, the only evidence of this is purely statistical with only accumulations of observational data over decades pointing towards the radically increased incidence of neurological disorder patients with a medical history of viral infections. The biological mechanism of how viral infections affect the nervous system several years later is still unknown. While there is a growing number of current studies dedicated to discovering this pathogenesis, there are still not many, but the statistical evidence to this unquestionable link continues to mount.
As we wait for scientists to discover the exact pathology of this fascinating and concerning connection, there are a myriad of questions that arise surrounding the most recent pandemic. Could the unique neurological symptoms of Long-COVID actually be a much earlier manifestation of a long-term impact that negates the risk of later degeneration? Could the coronavirus become the lone virus known to date that presents with both lasting, immediate and delayed neurological damage? Is the coronavirus going to cause a similar or possibly even more drastic increase in severe neurological disorders in decades to come due to the almost 112 million cases of COVID-19 infection reported in the United States alone (7)?
While none of those rather anxiety-inducing questions can most likely be answered any time in the next couple of decades or so, there are many others that can be answered and are not being addressed enough. Specifically, does the United States healthcare system and economy have the infrastructure in place that could treat and protect an unprecedented number of Americans with disabling neurodegenerative disorders? The United States currently spends approximately $100 billion each year on direct health care costs and lost economic productivity due to Alzheimer’s alone (8). If COVID-19 behaves similarly to other, more studied viruses, the United States could see a surge in direct health care costs, disability payments, and lost economic productivity that the current economy cannot feasibly support. Additionally, there would be an increased need for a variety of pharmaceutical treatments for neurological disorders as well as home healthcare workers and caregivers that the United States is already lacking. So until the scientific research can catch up, the United States needs to get a preparatory make-over to prevent a possibly pending healthcare and economic crisis that would ensue if COVID-19 follows in the footsteps of the last pandemic.
References:
Centers for Disease Control and Prevention. (n.d.). Long Covid or post-covid conditions. Centers for Disease Control and Prevention. https://www.cdc.gov/coronavirus/2019-ncov/long-term-effects/index.html
Mayo Foundation for Medical Education and Research. (2023, June 22). Covid-19: Long-term effects. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/coronavirus/in-depth/coronavirus-long-term-effects/art-20490351
University of Oxford News. Link between covid-19 infection and subsequent mental health and. University of Oxford. (n.d.). https://www.ox.ac.uk/news/2021-04-07-link-between-covid-19-infection-and-subsequent-mental-health-and-neurological
Cox, D. (2023, September 22). How past pandemics may have triggered rising cases of parkinson’s. BBC News. https://www.bbc.com/future/article/20220127-could-covid-19-still-be-affecting-us-in-decades-to-come
Mayo Foundation for Medical Education and Research. (2024, April 5). Parkinson’s disease. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/parkinsons-disease/symptoms-causes/syc-20376055
Wouk, J., Rechenchoski, D. Z., Rodrigues, B. C. D., Ribelato, E. V., & Faccin-Galhardi, L. C. (2023, January 23). Viral infections and their relationship to neurological disorders - archives of Virology. SpringerLink. https://link.springer.com/article/10.1007/s00705-021-04959-6
United States. Worldometer. (n.d.). https://www.worldometers.info/coronavirus/country/us/
Brown, R. C., Lockwood, A. H., & Sonawane, B. R. (2005). Neurodegenerative diseases: an overview of environmental risk factors. Environmental health perspectives, 113(9), 1250–1256. https://doi.org/10.1289/ehp.7567
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