An Overview of Post-viral Syndrome (PVS) including ‘Long COVID’

Post-viral syndrome (PVS) has come to the attention of doctors and the public more than ever before recently due to long-COVID. However, post viral illness is nothing new.

Recognition of post viral syndrome (PVS) started in the 1980’s around the time when I started practice. I was seeing a ‘mystery’ illness in my patients that didn’t fit a specific diagnosis, and eventually I found, and contacted Dr. Byron Hyde in Ottawa who dedicated his practice solely to research on PVS. At that time, it was called post-polio syndrome and names later changed to include myalgic encephalomyelitis (ME), chronic fatigue syndrome (CFS) and fibromyalgia-type illnesses. As a result of the inspiring conversations with Dr. Hyde, I became very passionate about learning all I could about post-viral illness.

PVS can be caused by many different microbial and viral infections including Epstein-Barr virus, cytomegalovirus, human herpesvirus, enteroviruses, Lyme disease and the more recently recognized, SARS-Cov-2 virus. It still remains unclear today, 34 years later, as to the origins and why viral symptoms can linger longer in the body. Basically, very little progress has been made within the Western medical community.

The symptoms may vary from person to person however, those most commonly seen in PVS (including long-COVID) are: profound fatigue, cognitive issues, joint and muscle pain, dizziness, headaches, weakness, depression, anxiety, non-restorative sleep, gastrointestinal problems and a flu-like feeling that linger long after the infection is cleared.

Overlapping symptoms similar in other chronic illnesses have created difficulties for diagnosis and there is not a set of specific tests to confirm a diagnosis so is often based on symptoms and exclusion of other underlying causes.

Long-COVID has heightened the awareness within the medical profession because it is more in the news lately, resulting in more doctors considering it as a diagnosis of post COVID-19 infection. But alas, many do not know where to start when it comes to treatments.

Considering the number of people who have had COVID-19, it could become a huge burden for many people and the medical system over the few years as more people develop post viral symptoms similar to CFS, ME and FM.

Currently it is estimated that over 23 million American adults are potentially living with this condition, while about 7 million are experiencing disabling symptoms. What is not commonly known is that the prevalence of long-COVID in children and adolescents was reported as 25.24% and the most prevalent clinical manifestations were mood symptoms (16.50%), fatigue (9.66%), and sleep disorders (8.42%). Conservative estimates in Canada report 300,000 and this is based on the World Health Organization’s estimate that at least 10 per cent of those infected with COVID-19 will experience long-haul symptoms. Canada has no definition of what long-COVID entails, making it more difficult to properly assess the actual number of people.

Long-COVID can happen even in people who had mild or no symptoms of COVID-19. The symptoms they had during the acute infection may not go away, once the infection is gone or can start after a person is feeling better and may come-on weeks later.

A large U.S. study published in the Lancet March 1, 2022 looked at whether vaccination protects against long covid and it showed the shots have only a slight protective effect:

Vaccination and long-Covid:  A large U.S. study of 13 million people published in the Lancet March 1, 2022 looked at whether vaccination protects against long covid.  The results found that risk falls only slightly; vaccines offer less protection against lingering symptoms than expected and offers protection from lingering symptoms by about 15%.

Although Western medicine does not have answers as to why this is happening, one theory that is currently being considered is that the virus ‘overloads’ the immune system, preventing healthy immune system resolution which causes ongoing inflammation. In my opinion, systemic inflammation is the foundation and main cause of all post viral syndrome symptoms.  I treated every patient with natural and sometimes prescription anti-inflammatory and other medications. Pain, cognitive problems, headaches, depression, gastrointestinal problems, and fatigue, can all be caused by inflammation.

Cytokines, one of the markers of inflammation, cause mitochondrial dysregulation. The mitochondria are the power stations in our cells that generate most of the chemical energy needed to power the cell’s biochemical reactions and produce energy (ATP). Without healthy mitochondria, cells die.

The SARS-CoV2 virus that causes Covid-19 also attacks the thyroid, kidneys, vascular system,  lungs, brain, gut, and the adrenal glands. Interestingly, chronic inflammation in the olfactory system (nasal cavities) is correlated with behavioral changes and thought to cause mood disorders like depression and anxiety.

Thyroid function abnormalities are common in COVID-19 patients, especially in severe cases. Research has found that levels of triiodothyronine (T3) the active form of thyroid hormone, and thyroid stimulating hormone (TSH) were lower in COVID-19 patients compared to the healthy group. This is often associated with high stress situations, and the individual has decreased thyroid function during the viral infection which may persist.

Adrenal glands are the primary organs that respond to a stressful situation, including the stress of a severe viral infection. Cortisol is the main stress hormone and low cortisol is considered the main condition that is diagnosed in people with long-COVID. In addition to the added stress of the infection, cortisol pathways are suppressed by dexamethasone (high dose cortisone) frequently administered as treatment for COVID-19. Salivary cortisol tests used to assess adrenal stress, showed very low levels of free cortisol and PCS symptoms overlap with hypoadrenal/low cortisol symptoms.

Impairment to the adrenal cortex was implicated following COVID-19 infection. The cortex secretes steroid hormones such as cortisol and aldosterone and precursor hormones that can be converted to sex steroids (androgens, estrogens). Autopsy studies in patients with COVID-19 revealed death of adrenal cortical cells and also identified the virus in the adrenal glands.

This information helps to understand the debilitating fatigue, brain fog, sleep problems, poor concentration and other symptoms related to adrenal fatigue in those with PCS. 

As with ME, and CFS, the post COVID symptoms may vary person to person depending on which organs were challenged the most with the virus. Some doctors completely separate ME, CFS and fibromyalgia as different conditions, and although it is true that the etiology, onset, other factors involved and symptoms may be slightly different, most people experience the same symptoms mentioned previously. No matter what virus and other factors are involved, post viral illness is very complex and challenging for the physician and frustrating and most difficult for the patient. My intention is not to over-simplify any form of PVS but rather give an overview and a starting point for people to use in order to overcome this debilitating condition.


Starting Point:

A full thyroid assessment should be done (TSH, T4, T3, antibodies), inflammatory markers such as C-Reactive protein, CBC, and if possible, a salivary cortisol and DHEA test from a naturopathic doctor.  Some people with severe symptoms may require prescription anti-inflammatories in the short term as well as low dose cortisol and thyroid hormones depending on the lab results and discussion with their health care practitioner.

Natural Supplements for PCS

Inflammation support: Palmitoylethanolamide (PEA), boswellia, curcumin, serrapeptase

Adrenal support such as AdrenaSense or other combined adaptogen formulas

Thyroid support – natural supplements such as ThyroSense or thyroid hormone if needed

Gut Support – Probiotics and prebiotics

Vascular supportNattokinase, omega-3 fatty acids

Brain phosphatidyl serine, *ginkgo biloba, or a combined formula such as Memory Boost

Mitochondrial regenerationCo-enzyme Q10, pyrroloquinoline quinone (PQQ)

*Do not take if you are on blood thinners

Kidney and lung function should also improve after a few months taking natural anti-inflammatory support.

Talk to the knowledgeable staff at the Vitamin Shop for more details on the supplements mentioned above.

Once again, this is simply an overview as post viral diseases are very complex, difficult to diagnose and in some cases challenging to treat. I am hoping this article provides you with enough information for a greater understanding as well as a place to start in order to improve your health. 


Araja, D. et al. Shadow Burden of Undiagnosed Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) on Society: Retrospective and Prospective. Journal of Clinical Medicine, 6 July 2021

Baja A, Colombo M, Headley JL, et al. Post-poliomyelitis syndrome as a possible viral disease

Journal of Infectious Diseases Volume 35, June 2015, Pages 107-116

Wang W, Su X, Ding Y, et al. Thyroid Function Abnormalities in COVID-19 Patients

Front. Endocrinol., 19 February 2021

Chen Y, Li X, Dai Y, et al. Endocrinology and COVID-19: A Cross-Disciplinary Topic, The Association Between COVID-19 and Thyroxine Levels: A Meta-Analysis

Front. Endocrinol., 04 January 2022 Vol. 2

Salzano C, Saracino G, Cardillo G. Possible Adrenal Involvement in Long COVID Syndrome. Medicina (Kaunas). 2021 Oct 11;57(10):1087.

NIH Reasearch matters June 28, 2022 Edition. —by Larisa Gearhart-Serna, Ph.D.

Lopez-Leon,S., Wegman-Ostrosky, T., Ayuzo del Valle, N.C. et al. Long-COVID in children and adolescents: a systematic review and meta-analyses. Sci Rep 12, 9950 (2022).

The Lancet Respiratory Medicine

NEWS| VOLUME 10, ISSUE 3, E30, MARCH 01, 2022

Do vaccines protect from long COVID?

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