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‘Long-COVID’: Understanding the long-term risks following a COVID-19 diagnosis

Regardless of case severity, many COVID-19 patients face serious persistent symptoms for months


As the pandemic has progressed, clinicians and scientists are becoming increasingly alarmed with what has been term “Long COVID” – continued symptoms of COVID-19 that last 3 weeks or more after the diagnosis.

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Dr. Sara Jahnke and Dr. Denise Smith served as panelists on the virtual roundtable “Long term health impacts of COVID-19.” Register here to watch the on-demand webinar.

Dr. Denise Smith contributed to this article.

Nearly 100 fire service personnel have died of complications related to their COVID-19 infections. While this number exceeds the line-of-duty deaths (LODDs) from all causes in previous years, the risk of dying from a COVID-19 infection, particularly for someone within the most common demographics of the fire service, is relatively low. Further, the infection is becoming less deadly as the medical and scientific communities become better equipped to respond to and treat severe cases, and mass vaccinations of older adults are leading to the weight of the diagnoses being more common in younger adults.

Many people, including many in the fire service, have asked, “Is it really that bad?” After all, most people will survive a COVID infection. This, in turn, has led to many individuals refusing the opportunity to vaccinate against the disease.

But death is not the only issue firefighters need to be concerned with when it comes to COVID-19. As the pandemic has progressed, clinicians and scientists are becoming increasingly alarmed with what has been term “Long COVID” – continued symptoms of COVID-19 that last 3 weeks or more after the diagnosis.

Among those hospitalized with the flu, 90% are fully recovered within 2 weeks of hospital discharge. Similar rates post-COVID-19 are not nearly as promising. Among those who have been hospitalized for COVID-19, 87% report symptoms even 2 months post hospitalization. Even among those with mild symptoms, more than one-third report symptoms continuing two weeks post-diagnosis.

Overall, approximately 10% of those are infected are classified as “Long COVID” cases.

What is “Long COVID”?

The long-term health effects of COVID-19 are just beginning to emerge. While there is still much that researchers and clinicians do not know, there are some concerning issues that are becoming clear.

For example, according to the WHO report “In the wake of the pandemic: Preparing for Long COVID,” approximately 25% of individuals who had COVID-19 still have physical symptoms one month after they became ill, and about 10% have symptoms that persist after 12 weeks.

Long COVID patients have a broad range of overlapping and often debilitating symptoms, such as muscle pain or chest pain, difficulty breathing or shortness of breath, and severe fatigue. The physical symptoms seem to be independent of the severity of the initial infection symptoms.

Pathological changes can lead to many clinic conditions:

  • Clotting disorders (stroke, myocardial infarctions, pulmonary embolism)
  • Hypertension and related disorders (aneurisms, valvular problems)
  • Pulmonary congestion, fibrosis (shortness of breath, coughing)
  • Cardiac damage (fibrosis increases risk of arrhythmias, high troponin, inflammation)
  • Excessive Immune response (cytokine storm, long-term inflammation)
  • Metabolic syndrome (altered blood glucose, insulin resistance, diabetes)
  • Neurological disorders (brain fog, altered mood, anxiety, depression)

While many COVID “long-haulers,” as they have been called, experience improving health after months of illness, it is often not a steady improvement, with multiple bouts of concerning symptoms, such as extreme fatigue, shortness of breath, and headache. Furthermore, concerning symptoms, such as clotting disorders can appear weeks or months after COVID-19, even in those who had a mild course of the illness. And we still do not know how long it will take for some individuals to return to their “normal” health because there are many long-haulers who have not yet regained their health.

The causes of long-term COVID-19 are not fully understood, but there is evidence that many of the persistent symptoms are related to endothelial disruption. The endothelium is the thin layer of cells that lines the blood vessels – so it is present in every body system that has a blood supply, including blood vessels in the heart, lungs, brain, kidneys, muscles, etc. This helps explain why so many organ systems are involved with COVID-19 or the recovery from COVID-19. The endothelium plays a key role in inflammation, permeability and blood clotting and thus is involved in many COVID-19 symptoms, such as the exaggerated inflammatory response, congestion in different tissues and clot formation.

Behavioral health and cognitive impact

The long-term impacts of COVID extend beyond the physical impact. In a study of nearly a quarter million medical records, Dr. Maxime Taquet and colleagues followed patients through their medical records. In the 6 months after being diagnosed with COVID-19, 30% of patients had a subsequent psychological diagnosis – most often anxiety of depression. Those who had contracted COVID were also more likely to develop dementia, neurologic disorders or stroke.

Arguably, the impact of the pandemic could have impacted patients in general and lead to more psychological challenges. To examine this, the team compared rates of diagnoses and found that those who had contracted COVID-19 were significantly more likely to be subsequently diagnosed with a psychologic or neurologic diagnosis compared to those who had other diagnoses, such as non-COVID respiratory diseases or the season flu. Most alarming, and surprising, was that the chances of a subsequent diagnosis were unrelated to the severity of COVID-19 symptoms.

The precise reason behind the cognitive and psychologic impact is not well understood and is currently being studied. Some possible reasons for the impact may be related to changes in oxygen levels, endothelial disfunction, alteration in blood flow to the brain, or inflammation.

The fire service impact

COVID-19 results in a spectrum of illness, from being asymptomatic to pneumonia and organ damage, and even death. It is now clear that recovery can be reasonably quick or excruciating long and complicated. Prevention remains a top priority. For those who have recovered from or are recovering from COVID-19, it is important to watch for potential long-term symptoms and to allow adequate time for the body to recover. The fire service will need to be attentive to the ability of firefighters to respond to full operational capacity following a prolonged recovery period.


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About the co-author

Dr. Denise Smith is a professor at Skidmore College and a research scientist at the Illinois Fire Service Institute (IFSI). Dr. Smith focuses on the relationship between heat stress and cardiovascular function. A significant portion of her research focuses on the cardiovascular strain associated with firefighting activity. She has published several articles the effects of firefighting on cardiovascular function, coagulatory potential, immune function and hormonal status. Dr. Smith has also conducted several laboratory studies designed to identify specific components of firefighting activity (work performed, heat stress, sympathetic nervous stimulation) that are responsible for specific physiological responses to the combined stress of firefighting. Dr. Smith received her Ph.D. from the University of Illinois in 1990 and her master’s degree in 1985.

Sara Jahnke, PhD, is the director and a senior scientist with the Center for Fire, Rescue & EMS Health Research at the National Development & Research Institutes - USA. With over a decade of research experience on firefighter health, Dr. Jahnke has been the principal investigator on 10 national studies as well as dozens of studies as a co-investigator. Her work has focused on a range of health concerns, including the health of female firefighters, behavioral health, risk of injury, cancer, cardiovascular risk factors, and substance use, with funding from the Assistance to Firefighters Grant R&D Program, the National Institutes of Health and other foundations. Jahnke has more than 100 publications in the peer-reviewed medical literature. Awards include the 2019 Endowed Lecture at the annual conference of the American College of Epidemiology; the 2018 President’s Award for Excellence in Fire Service Research as well as the Excellence in Research, Safety, Health & Survival Award, both from the International Association of Fire Chiefs (IAFC); and the 2016 John Granito Award for Excellence in Firefighter Research from the International Journal of Fire Service Leadership and Management. Connect with Jahnke on LinkedIn, Twitter or via email.