Understanding Long COVID

Overview 

   According to the CDC Long COVID is, “a chronic condition that occurs after SARS-CoV-2 infection and is present for at least 3 months. Long COVID includes a wide range of symptoms or conditions that may improve, worsen, or be ongoing.” Symptoms of Long Covid include: extreme tiredness, problems with memory, feeling lightheaded, and problems with taste and smell. Long-COVID affects about 5% to 10% of people who’ve had a COVID infection. The actual cause of Long COVID is still a mystery to doctors and scientists today. However, it is persistent that each time a person is infected with SARS-CoV-2 they have a greater risk of developing Long COVID.

Underlying Hypotheses for the cause of Long COVID
While the exact causes of Long COVID remain unclear, researchers have proposed a couple of leading hypotheses to explain the condition 

1. Viral Persistence 

   One hypothesis suggests that remnants of the SARS-CoV-2 virus, such as viral RNA or proteins, may remain in the body even after the acute infection has resolved. These viral fragments could linger in tissues such as the lungs, gut, or nervous system, continuously triggering the immune system. Studies have identified traces of viral RNA in tissues months after initial infection, particularly in the gastrointestinal tract. Persistent viral presence could sustain low-grade inflammation, causing symptoms like fatigue and brain fog. 

2. Autoimmune Response 

   Another possible cause of Long- COVID is the way the viral proteins behave. The virus actually causes COVID-19 and can attack healthy tissues. This reaction could result from “molecular mimicry” where viral proteins resemble human proteins, leading the immune system to target its own cells mistakenly. Autoimmune responses may explain the prolonged inflammation and infection in the body. It can also explain the joint pain and organ damage observed in some Long- COVID patients. 

Cellular Changes in the Body

There are various cellular changes in the body caused by Long COVID. The 3 most common cellular changes are:

1. Immune System Dysregulation

   Long COVIS often involves persistent activation of the immune system. Patients exhibit increased activity in innate immune cells and a reduction in naive T and B cells which are essential in responding to new infections. Additionally, elevated levels of inflammatory markers such as cytokines and interferons, persist long after an acute COVID-19 infection. This sustained immune response can lead to “immune exhaustion” where the body struggles to regulate inflammation and infection effectively. This dysregulation explains why Long COVID patients frequently report feeling fatigued, joint or muscle pain, and brain fog. The hyperactive immune system can also cause autoimmune reactions, where the body starts attacking its own tissues. 

   
   2. Endothelial Cell Damage

   SARS-CoV-2 infects and damages endothelial cells, which line the inside of blood vessels. These cells play a crucial role in maintaining vascular health and regulating blood flow. Damage to the endothelial cells can lead to the formation of microclots and impaired blood circulation. It can also lead to the blood cells not being able to carry the nutrients the body needs.  This dysfunction can reduce oxygen delivery to tissues, causing fatigue and other symptoms. The vascular damage can result in chest pain, shortness of breath, and an increased risk of cardiovascular complications like heart attacks or strokes. It also contributes to brain fog by reducing blood flow to the brain. 

   3. Mitochondrial Dysfunction

   The Mitochondria is the “powerhouse” of the cells and is responsible for producing energy. The virus causing COVID-19 may disrupt mitochondrial function, leading to reduced energy and production of oxidative stress. This dysfunction can account for symptoms like extreme fatigue, muscle weakness, and exercise tolerance. A lack of cellular energy may also impair the body’s ability to repair tissues and recover fully. This can cause the prolonged symptoms that are present in Long- COVID. 

Risk Factors

Most research finds that Long-COVID is diagnosed more often in females of any age than males. People who have a previous cardiovascular disease or an autoimmune disease are much more likely to be affected by COVID-19 due to a compromised immune system. People who haven’t received the COVID-19 vaccine are also at more risk of developing Long-COVID. Belonging to an ethnic minority has also been associated with an increased risk of Long-COVID. In a study by the NIH, “Black and Hispanic people are more likely than White people to experience certain symptoms associated with Long COVID. Black and Hispanic people are more likely than White people to experience certain symptoms associated with Long COVID.” 

Diagnostic Tests and Treatment of Long-COVID 

While there isn’t a single test that determines if a patient has Long-COVID or not, healthcare providers can look into various factors such as health history, previous COVID-19 diagnosis, and a health examination. Providers can also do blood tests, chest X-rays, electrocardiograms, and lung function tests. There isn’t a single treatment used for Long-COVID but depending on the severity of symptoms medications may be used. Stellate ganglion blocks and olfactory retraining can help bring the sense of taste and smell back. In patients who have been severely affected by Long- COVID therapies can be implemented such as physical therapy and pulmonary rehabilitation. 

Works Cited

CDC. (2024, July 11). Long COVID Basics. CDC. Retrieved December 19, 2024, from https://www.cdc.gov/covid/long-term-effects/index.html

Cleveland Clinic. (2023, June 19). Long COVID. Cleveland Clinic. Retrieved December 19, 2024, from https://my.clevelandclinic.org/health/diseases/25111-long-covid

Davis, H. E., McCorkell, L., & Topol, E. J. (2023, January 13). Long COVID: major findings, mechanisms and recommendations. National Institute of Health. Retrieved December 19, 2024, from https://pubmed.ncbi.nlm.nih.gov/36639608/

NIH. (2023, April 6). Symptoms of Long COVID Differ for People of Different Racial and Ethnic Groups. National Institute of Health. Retrieved December 19, 2024, from https://covid19.nih.gov/news-and-stories/symptoms-long-covid-differ-people-different-racial-and-ethnic-groups#:~:text=Compared%20with%20White%20adults%2C%20Black,like%20brain%20fog%2C%20or%20fatigue.