COVID-19 is a disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), leading to acute respiratory system illnesses. Therefore, almost no one would consider this disease as chronic. Post-acute sequelae of SARS-CoV-2 infection (PASC), also known as COVID-19 long-haul syndrome, has been extensively discussed in the medical community recently. Many studies have attempted to define PASC, with the most common definition being the persistence of symptoms for more than three months after the initial symptoms appeared. Currently, there is limited knowledge about PASC, yet it continues to affect COVID-19 survivors. Besides, PASC affects multiple organ systems, not just the respiratory system [1].
What is PASC?
PASC refers to a series of new, recurrent, or persistent health problems experienced by individuals after their initial COVID-19 infection. Most people who contract COVID-19 experience improvement within days to weeks after infection. Therefore, PASC is typically determined at least four weeks after the infection. Anyone who has had COVID-19 is at risk of experiencing PASC. Most PASC patients start developing symptoms a few days after their initial infection, although some may not be aware of their PASC during their first infection.
Currently, there are no diagnostic criteria for PASC. It is diagnosed through case analysis of various symptoms, which may also be attributed to other health issues. Thus, diagnosing PASC requires a comprehensive evaluation by a medical professional. Symptoms in PASC patients can persist for over four weeks or even months, and they may come and go. For some individuals, PASC can last for several months or years, sometimes leading to disability [2].
What are the symptoms of PASC, or “long COVID”?
According to research from the U.S. CDC, the symptoms of PASC can be broadly categorized as follows [2]:
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General Symptoms
Fatigue that disrupts daily life, post-exertional symptoms (also known as post-exertional malaise), and fever.
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Respiratory and Cardiovascular Symptoms
Shortness of breath, cough, chest pain, and rapid or pounding heart (also known as palpitations).
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Neurological Symptoms
Difficulty thinking or concentrating (sometimes referred to as “brain fog”), headaches, sleep problems, changes in smell or taste, depression, or anxiety.
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Digestive System Symptoms
Diarrhea and abdominal pain.
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Other Symptoms
Joint or muscle pain, rashes, changes in the menstrual cycle.
A study analyzing data from 4,182 COVID-19 patients found that 558 individuals (13.3%) experienced symptoms lasting for ≥28 days, 189 (4.5%) for ≥8 weeks, and 95 (2.3%) for ≥12 weeks. Common symptoms of PASC included fatigue, headaches, difficulty breathing, and loss of smell, with a higher likelihood of developing PASC associated with increasing age, higher body mass index, and female gender. Additionally, having more than five symptoms during the first week of illness was positively correlated with developing PASC [3]. Current research on PASC is limited, and more data is needed to confirm these findings.
Related Risk Factors may include:
- Female gender
- Early onset of more than five symptoms
- Early onset of breathing difficulties
- Previous mental health issues and specific biomarkers such as D-dimer, CRP, and lymphocyte counts [1].
However, further research is needed to confirm these risk factors [1].
How to Prevent PASC?
The best way to prevent PASC is to protect oneself and others from infection. Timely vaccination against COVID-19 can help prevent COVID-19 infection and potential severe illness. Studies have shown that individuals who are vaccinated and experience breakthrough infections report fewer cases of PASC compared to those who are unvaccinated [2]. Personalized recovery training is recommended for some PASC cases, but there is currently limited strong evidence for effective prevention of PASC, so avoiding infection remains the primary means of prevention.
How to Improve PASC?
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Fish Oil
Long-term effects on the nervous system are possible in PASC. Research suggests that long-chain Omega-3 polyunsaturated fatty acids may have a favorable impact on immune, inflammatory, oxidative responses, and psychological neurology at various stages of COVID-19 infection. Omega-3 polyunsaturated fatty acids can slow down chronic inflammation, providing a potential way to improve PASC symptoms. They might also help with fatigue, headaches, and brain fog, conditions potentially related to damage to olfactory sensory neurons, leading to increased cerebrospinal fluid resistance, and subsequent central nervous system accumulation of toxic substances [4].
Therefore, detoxifying toxic substances is an essential task in treating brain fog or PASC symptoms [4]. Omega-3 polyunsaturated fatty acids may not only reduce the production and aggregation of amyloid-β (a protein with neurotoxic properties) in the brain but also assist in its clearance. Thus, Omega-3 polyunsaturated fatty acids are recommended for treating neurological complications in PASC by improving lymphatic circulation and reducing toxin accumulation [4].
However, more research and clinical trials are needed to support the use of Omega-3 polyunsaturated fatty acids for PASC [4].
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Vitamin D
Vitamin D can act as an immune modulator in the human body and has been shown to have preventive and improvement effects on upper respiratory infections. It can suppress excessive inflammatory responses and accelerate healing processes in affected areas, particularly in lung tissue [7]. Some studies suggest that vitamin D may be helpful in reducing COVID-19 infection, such as virus inactivation, inflammation suppression, and support for immune cell activity [8]. However, more evidence is needed to support whether vitamin D supplementation can improve PASC [7].
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Vitamin C
Fatigue is common not only in cancer patients but also after viral and other infections. A review of nine clinical studies supplementing vitamin C to patients with fatigue found that the fatigue group supplemented with vitamin C significantly improved sleep disturbances, concentration problems, depression, and pain. Fatigue in PASC patients may be related to oxidative reactions, inflammation, and circulatory disturbances, making vitamin C supplementation a potential relief for fatigue [9]. Some research suggests that intravenous vitamin C administration during acute COVID-19 infection may reduce the severity of the disease and the likelihood of developing PASC [10].
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Ganoderma Lucidum (Reishi Mushroom)
Ganoderma lucidum polysaccharides and triterpenoids have long been considered to help regulate the immune system and have antiviral, antioxidant, and anticancer effects. Its immunomodulatory and antiviral properties may be a potential way to combat the current pandemic. A clinical study provided COVID-19 patients with Ganoderma supplementation and found that those who should be in the recovery phase, based on IgG (indicating past infection) and IgM (indicating recent or active infection) levels, had significantly more lymphocytes, and their hemoglobin, red blood cell volume, red blood cells, and platelet counts were not significantly reduced due to infection. This suggests that Ganoderma supplementation can help alleviate virus infection and treat COVID-19 infection [13].
Please note that while these methods are being explored, further research and clinical trials are necessary to establish their effectiveness in improving PASC symptoms.
Summary
Many questions about COVID-19, especially with regards to the research data, remain unknown and have not reached a consensus. COVID-19 long-haul syndrome deserves serious attention from the scientific and medical community. Assuming that at least 10% of COVID-19 survivors experience long-haul symptoms, it is estimated that at least five million people globally are facing COVID-19 long-haul [1]. Currently, there is no medication proven to improve or alleviate the symptoms of COVID-19 long-haul. Therefore, the best way to prevent the acute illness and long-term impacts of COVID-19 is to, first and foremost, avoid infection. Effective measures to reduce the risk of infection include social distancing, wearing masks, and vaccination.
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