Long COVID: Symptoms, Causes, and Risk Factors

A major new NIH initiative has been announced to identify the causes and ultimately the means of prevention and treatment of "Long COVID."

Symptoms

Acute COVID-19 is a highly inflammatory illness. 

Most people with COVID-19 recover within two weeks. Some, as reported in [30], with so-called Long Covid (symptoms lasting longer than three weeks), continue to experience excessive fatigue, breathlessness, headache, insomnia, muscle fatigue and pains, chest pains, persistent cough, intermittent fevers and brain fog.

Causes

In the post-acute phase, 

• Inflammation
• Immune activation
• Long-term dysregulation of virus-specific immune responses 

have been consistently identified in peripheral blood. 

These immune responses have been associated with a variety of factors including:

• Clotting dysfunction
• Reactivation of latent viral infections such as Epstein Barr Virus (EBV)
• Autoimmune responses

Importantly, there is a growing body of evidence that persistent SARS-CoV-2 RNA or protein can be detected in various tissue compartments for many months following acute infection. This may explain, at least in part, ongoing aberrant immune responses, inflammation, and clinical symptomatology.

Risk Factors

It’s unclear why some people develop long Covid and others don’t, but four factors appear to increase the risk:^[37]

• High levels of viral RNA early during an infection
• The presence of certain autoantibodies
• The reactivation of Epstein-Barr virus
• Having Type 2 diabetes

The study finds about 10 per cent had symptoms for a month, with between 1.5 and 2 per cent after three months. The median age of those with Long Covid is 45, and women are more likely to be affected.

Ongoing Research

It is important to note that the research on long COVID is still ongoing, and there is still much that we do not know about this condition.

References

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5. [WEBCAST REPLAY] COVID-19 Pandemic Update: Analysis From Neil Howe & Daryl Jones
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• Clinicians then assess potential causes of troponin elevation, including hyperinflammation, which may respond to immunosuppressive therapy.
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• Nearly 72% of American adults are overweight (25 < BMI < 30) or obese (BMI ≥ 30)
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• Here, this could include a combination of vaccines and antiviral innovations to target the virus. Specifically, combination therapy approaches to target the adaptive immune response (e.g., vaccines, antibody treatments) and another inhibiting viral innate immune antagonist proteins (e.g., Orf6 and Orf9b) or activating the innate immune response, could be the most effective. Perhaps with this approach, we may be able to get ahead of viruses before they reach pandemic levels.
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