Long COVID, Spike Protein and Autoimmunity

As we learn more about the pathogenesis of Long COVID, the presence of an autoimmune process appears to be a prevailing mechanism in how the condition manifests.

The following video og blog post goes through some of the research on this subject, why autoimmunity may have occurred in some individuals in response to viral infection and vaccine administration, in addition to concepts surrounding autoimmunity in general.

The information in this video and blog is for educational purposes only and, therefore, is not intended to be used to diagnose or substitute medical advice or treatment. You should always consult your medical doctor if you intend to make changes based on this information and you should never disregard medical advice or cease taking medication because of it.

Autoimmunity and Long COVID, how the Immune System May Be Involved

One of the key theories emerging in Long COVID research is that autoimmunity may play an important role in the development of ongoing symptoms. A number of studies have shown higher levels of autoantibodies in people with Long COVID, and increasing evidence suggests that many patients develop latent autoimmune activity in around 80 percent of cases, or multiple autoimmune processes in around 60 percent.

Because of these findings, researchers have begun to describe SARS-CoV-2 as a potential autoimmune-inducing virus, alongside Epstein-Barr Virus and Human Herpesvirus-6. Understanding why this immune reaction develops, and what may contribute to it, can help explain why some people experience long-lasting symptoms following infection.

How SARS-CoV-2 May Trigger Autoimmune Activity

Research has shown that autoimmune processes may develop through cross-reactivity between the spike protein of SARS-CoV-2 and certain human tissues. Some studies have demonstrated that antibodies targeting the spike protein can react with many different tissue types, suggesting a high level of potential immune confusion.

These antibodies have been shown to react with:

• barrier proteins in the gut and brain

• thyroid tissue

• skin and liver tissue

• muscle and nervous system structures

When barrier proteins are affected, this may contribute to issues such as “leaky gut” or neuro-inflammation, which can help explain symptoms like brain fog, fatigue, and widespread sensitivity. Because these tissues exist throughout the body, this mechanism may help explain why Long COVID can appear as such a systemic, multi-symptom condition, with different people experiencing different manifestations depending on genetics and predisposition.

Autoimmunity Rarely Develops From a Single Event

Autoimmune disease usually does not arise from one isolated trigger such as a single infection or vaccine exposure. Instead, it typically develops gradually over time as multiple factors place strain on the immune system, until tolerance breaks down.

Immune tolerance refers to the body’s ability to recognise what belongs to us and what does not. When tolerance is lost, the immune system becomes more reactive, more inflammatory, and struggles to switch off. This process is often associated with increases in inflammatory cytokines such as IL-6, and reductions in regulatory T-cells, which normally help keep the immune system balanced.

SARS-CoV-2 may therefore act as a final trigger in people who already have underlying immune stress or imbalance. Much of the severity of COVID-19 relates not only to the virus itself, but to how an individual’s immune system responds to it, which is strongly influenced by lifestyle, environment, stress levels, nutrition, and existing health factors.

Factors That May Contribute to Immune Dysregulation

Toxins and Environmental Exposure

Many people with Long COVID report prior exposure to mould or mycotoxins, particularly in damp or water-damaged environments. These toxins have been shown to affect immune function and may increase susceptibility to inflammatory and fatigue-related symptoms. Heavy metals and broader toxin accumulation may also place strain on immune and detoxification pathways.

Clinically, people often experience improvement when they are removed from ongoing toxin exposure and supported in detoxification, with reported reductions in fatigue, MCAS-type symptoms, and immune reactivity.

Latent Viral Reactivation

Underlying or dormant viral infections, including Epstein-Barr Virus and Herpes-type viruses, may become reactivated when the immune system is overwhelmed. These viruses can affect mitochondrial function and energy production, which may contribute to fatigue. They have also been associated with autoimmune conditions such as Lupus, MS, and autoimmune thyroid disease.

Microbiome Imbalances

Elevated levels of pathogenic or opportunistic microbes such as yeast or candida in the gut is also commonly observed in some individuals with chronic symptoms. Candida can trigger inflammatory immune responses and increase interleukin-17, which in turn may reduce regulatory T-cell function. Factors such as high sugar intake, repeated antibiotic use, and stress may contribute to this pattern.

Food Sensitivities and Leaky Gut

Food sensitivities often emerge when intestinal permeability increases. When whole food particles pass through the gut lining and interact with the immune system, the body may begin reacting to foods such as gluten or dairy. Stress, inflammation, and lifestyle pressures may contribute to this breakdown in barrier integrity.

Genetics and Susceptibility

Genetics influence whether someone is more predisposed to certain autoimmune conditions, however genes alone are rarely sufficient. Autoimmunity usually develops when genetic susceptibility combines with the right environmental triggers, such as immune stress, inflammation, or intestinal permeability.

Stress and Trauma

Chronic stress and psychological trauma are known to increase pro-inflammatory cytokines and can play a significant role in the loss of immune tolerance. For many people, the last few years have involved prolonged stress, which may have contributed to immune vulnerability prior to infection.

What This Means for Long COVID

For many individuals, Long COVID is unlikely to result from the virus alone. Instead, it may represent the point at which an already strained immune system becomes overwhelmed, and remains switched on.

In mainstream care, autoimmune conditions are often managed with steroid or immune-suppressing medications, which aim to reduce immune attack but do not typically explore why tolerance was lost in the first place.

A functional medicine approach instead asks:

• What has contributed to immune activation?

• Which factors are still perpetuating inflammation?

• What underlying triggers can be reduced or removed?

By addressing contributing factors such as toxins, infections, gut imbalances, stress, and lifestyle drivers, many people may experience improvement as the immune system gradually calms.

This process can feel complex, however it can also be empowering, because it highlights areas where meaningful change is possible, rather than assuming that symptoms are inevitable or permanent.

Autoimmunity Exists on a Spectrum

Autoimmune responses typically progress through stages:

1. Silent autoimmunity
Autoantibodies are present, however there is little or no disruption to tissue or function.

2. Autoimmune reactivity
Symptoms develop and physiological processes are affected, although significant tissue damage has not yet occurred.

3. Full autoimmune disease
Autoantibodies, widespread inflammation, tissue destruction, and clear diagnostic criteria are present, leading to conditions such as Lupus, MS, or autoimmune thyroid disease.

Many people with Long COVID find themselves in the earlier stages of this spectrum, where symptoms are present but diagnostic tests are not severe enough to meet disease criteria. This can leave patients without answers or support, even though the immune system is clearly under strain.

Functional medicine aims to intervene before progression reaches later stages, by reducing immune load and helping restore tolerance where possible.

Final Thoughts

If you suspect that autoimmunity or immune activation is contributing to your Long COVID symptoms, it may be helpful to begin exploring the factors that may be adding to your overall inflammatory burden.

Rather than waiting until symptoms progress to the point of formal diagnosis, supporting immune balance earlier can sometimes prevent further deterioration and improve quality of life.

Autoimmunity is rarely the result of a single trigger, and more often reflects the cumulative impact of many influences over time. By gradually identifying and reducing these contributors, it may be possible to help bring the immune system back within a healthier level of tolerance.

References:

https://pubmed.ncbi.nlm.nih.gov/33584709/ – Reaction of Human Monoclonal Antibodies to SARS-CoV-2 Proteins With Tissue Antigens: Implications for Autoimmune Diseases

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8924736/ – Autoimmunity is a hallmark of post-COVID syndrome

https://pubmed.ncbi.nlm.nih.gov/34957554/ – New-onset autoimmune phenomena post-COVID-19 vaccination