Introduction
Long COVID-19 is a condition characterized by persistent symptoms and complications for several days or months after initial infection with SARS-CoV-2 or coronavirus (the virus that causes COVID-19). It is quite common, with three or four people reporting symptoms six months after recovering from COVID-19 infection. The most commonly reported symptoms include muscle weakness, insomnia, and fatigue. Research suggests the composition of the gut microbiome can be linked to the risk of developing long COVID-19 several months after initial infection. Gut microbiome profiling may help identify those who are at a greater risk of developing the condition.
What Causes Long COVID-19?
It is unclear exactly what causes long COVID-19 or why some individuals are more likely to develop it. An exaggerated immune response, the psychological consequence of a critical illness, or cell damage may result in the development of long COVID-19. The growing research on the topic has suggested the cause of COVID-19 severity can be the gut microbiome (numerous bacteria, fungi, and other microbes that live in the digestive tract).
What Are the Different Hypotheses Supporting the Symptoms of Long COVID?
Different hypotheses or theories formulated to explain the ongoing symptoms in the post-acute phase of COVID-19 are:
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During acute COVID-19, tissue damage due to direct viral toxicity, blood vessel injury, macro thrombosis (larger blood clots blocking the blood vessels) or micro thrombosis (blood clots smaller in size blocking the blood vessels), and incomplete healing processes may cause persistent symptoms.
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Incomplete virus clearance from the body and persistent low-level virus replication or the presence of viral antigens in the body can affect the recovery process.
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The immune response to SARS-CoV2 may instigate an autoimmune attack damaging the specific tissues.
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Outcomes of aggressive therapy (done for setting the post-critical illness) may contribute to incomplete or prolonged recovery.
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Increased awareness about the body and anticipated association of diffuse symptoms to COVID-19 may increase the reporting of symptoms that were unnoticed by healthcare professionals.
How Is Gut Health Associated With COVID-19?
According to a research study, the gut microbiome influences the disease severity and outcome of COVID-19. It also stated that poor gut health could cause lasting COVID-19 symptoms. Imbalances in the composition of the microorganisms in the digestive tract can contribute to persisting inflammatory symptoms. It was noted that the gut microbiota was remarkably changed in patients with COVID-19 compared to non-COVID-19 people, irrespective of their medication.
An imbalanced gut microbiome causes inflammation and epithelium breakdown, increasing the levels of angiotensin-converting enzyme 2, which is the target of coronavirus (SARS-CoV 2). An imbalance or disrupted microbiome is when the digestive tract loses beneficial microorganisms and becomes a breeding ground for harmful microbes.
A specific composition of the gut microbiome may make a healthy individual susceptible to COVID-19 infection by increasing the levels of pro-inflammatory bacterial species correlating with increased levels of pro-inflammatory cytokines and elevated disease severity.
Disruptions to the bi-directional immune system- microbiome dialogue are believed to be the cause of chronic inflammatory diseases like ulcerative colitis and acute systemic multi-organ dysfunction along with abnormal cytokine production. An imbalance of the gut microbiome also contributes to elevated pro-inflammatory cytokine production that can worsen the severity of COVID-19 infection.
What Are the Gut-Associated Symptoms Seen in COVID-19 Patients?
While life-threatening coronavirus infection is mostly associated with respiratory insufficiency or worsening of underlying comorbidity, up to 50 percent of patients with acute infection experience gastrointestinal symptoms. Gastrointestinal symptoms are seen because the intestinal cells are prone to infection by severe acute COVID infection. The common gastrointestinal symptoms seen in COVID patients include:
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Vomiting.
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Stomach pain.
The uncommon gastrointestinal signs and symptoms include;
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Acid reflux (stomach acid flows back into the food pipe and irritates the lining of the food pipe).
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Indigestion.
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Colitis (inflammation of the intestine).
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Gastrointestinal bleeding (characterized by blood in the stool or vomit).
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Belching (burping or releasing excess air in the stomach through the mouth).
Conclusion
The gut microbiomeis responsible for a number of functions like breaking down toxins, making energy for cells, regulating digestion, and activating the immune system against viral attacks. It is clear that if the gut microbiome is disturbed or imbalanced, it can cause a ripple effect of adversities in the body. There are several factors that can affect gut health, including medication, high sugar intake, poor diet, and stress.
