A significant part of recovered Covid patients seem to suffer from "long Covid": a number of symptoms (including fatigue) lasting for at least months. Some of these symptoms can be explained by incorrect blood levels. Also, a significant number of patients die from complications caused by blood-cloths.
My theory for the viral mechanism is: The ACE2 receptor is part of the renin–angiotensin system that regulates blood levels. Normally this receptor receives angiotensin as a signal. The virus pretends to be angiotensin (spike) to enter the cell. The immune system learns from dying cells and recognizes the virus, sometimes by its spike. This spike is similar in shape to angiotensin and the immune system could now recognize angiotensin as virus. It will attack angiotensin and disturb the renin-angiotensin pathway. This can lead to blood cloths (somehow). The immune system thinks there are still viruses present and will keep going for a long time.
Could this be the case?
Propable, it can be. But there are so many symptoms after COVID, and they can have different reasons. For example, some studies show, 70% patients have a COVID myocarditis for 2 monthes after. It also can be reason for fatigue.
Great question and answer by Maria indicating that that post-COVID long haul or
long COVID affects so many people since COVID-19 and how it interacts with pre-existing conditions are so multifactorial. In some it may be the chronic on-going inflammation due to ongoing cytokine surges or storms that are periodically shed from the adipose depots due to high inflammation in the adipose crown-like structures and ACE2 being bound by the SARS-CoV-2 receptor and in others it may be the impaired glucose tolerance and even T2DM or in some the development of acute onset T1DM with either producing either transient or chronically increased levels of glucose and instigating glucotoxicity please see the recently published paper on
An Immediate and Long-Term Complication of COVID-19 May Be Type 2 Diabetes Mellitus:
doi:
https://doi.org/10.3390/cells9112475
Melvin R Hayden
University of Missouri School of Medicine
Columbia, Missouri USA
Endothelial cell infection and endothelitis (1) possibly explains all the long-term complications in long-COVID-19 patients (2) or Long haulers. These symptoms are more severe in severe or critically affected patients even up to months later.
This is why patient may have brain fog, fatigability, breathlessness, palpitation, muscles weakness, and different psychiatric symptoms weeks and months after apparent recovery from COVID-19.
1. Article Endothelial cell infection and endotheliitis in COVID-19
2. https://www.thelancet.com/journals/eclinm/article/PIIS2589-5370(20)30330-8/fulltext
We must remember that the endothelial activation and dysfunction we observe in COVID-19 and SARS-CoV-2 may be pre-existent in many people due to age metabolic syndrome including a multifactorial mechanism with great crosstalk. Importantly in COVID-19 there exists VIRAL LOAD or Storm (reducing the positive effects of ANG(1-7) MasR) , Redox Storm (resulting in endothelial activation and dysfunction) and Cytokine surges or storm that can each affect endothelial activation and dysfunction and endothelitis! The long-haul long COVID syndrome is affecting many people with "recovering" and yet the persistence of long COVID symptoms.
I suggest two following papers:
Endothelial activation and dysfunction in MetS, T2DM and COVID-19
Article Endothelial activation and dysfunction in metabolic syndrome...
and the new paper to better understand the role of these multiple storms in COVID-19
https://doi.org/10.3390/cells9112475
Melvin R Hayden
University of Missouri School of Medicine
Columbia, Missouri