A viral spike protein is a structure that projects from the surface of an enveloped virus, giving coronaviruses their characteristic appearance. The protein’s primary function is to allow the virus to penetrate host cells and begin infection. This action is often compared to a key fitting into a lock; the spike protein is the ‘key’ that binds to specific receptors on our cells, which act as the ‘lock.’
This mechanism of entry makes the spike protein a focus for scientific research, particularly in developing antiviral therapies and vaccines. By understanding these proteins, scientists can devise ways to block their action and prevent viral infection.
The Role of Spike Proteins in Infection and Immunity
The spike protein on the SARS-CoV-2 virus is adapted to bind to a receptor on human cells known as angiotensin-converting enzyme 2 (ACE2). This binding is the first step for the virus to enter the cell and replicate. The spike protein itself is composed of two main parts: the S1 subunit, which attaches to the ACE2 receptor, and the S2 subunit, which mediates the fusion of the viral envelope with the host cell membrane. This fusion allows the virus’s genetic material to enter the cell, hijacking its machinery to produce more viruses.
In response, mRNA vaccines were developed to use this same mechanism for a protective purpose. These vaccines provide cells with instructions to produce a harmless, modified version of the spike protein. The vaccine-generated mRNA does not enter the cell’s nucleus and is quickly broken down after the protein is made.
Once these harmless spike proteins are produced, the immune system recognizes them as foreign. This triggers an immune response, leading to the production of neutralizing antibodies and the creation of memory T-cells and B-cells. This process teaches the immune system to fight off the actual virus without exposure to a live infection.
Concerns About Persistent Spike Proteins
A growing area of scientific inquiry is the hypothesis that in some individuals, spike protein fragments might persist in the body longer than expected after an infection. Researchers are investigating if this persistence could be a factor in Post-Acute Sequelae of COVID-19 (PASC), or ‘long COVID.’ The theory suggests that lingering viral components, including the spike protein, could be stored in tissue reservoirs like the gut and drive chronic inflammation.
Studies have detected SARS-CoV-2 genetic material and proteins in gut and stool samples months after the initial infection, lending support to the idea of a viral reservoir. A leading hypothesis suggests that persistent spike protein in the bloodstream could lead to ongoing symptoms, including:
- Profound fatigue
- Cognitive issues often described as ‘brain fog’
- Memory problems
- Shortness of breath
- Cardiovascular issues like heart palpitations
It is important to frame this as an active area of research, as the direct causal link between persistent spike protein and these symptoms is not yet fully understood.
Investigated and Proposed Therapeutic Strategies
In the search for ways to address symptoms associated with post-COVID conditions, various therapeutic strategies are being investigated. These range from enzymes and supplements to repurposed pharmaceuticals, each with varying levels of scientific evidence. The idea behind many of these is to either break down the protein or mitigate the inflammation it is hypothesized to cause.
Enzymes and Supplements
Among the most discussed substances are enzymes like nattokinase, derived from fermented soybeans. Laboratory studies have shown that nattokinase can degrade the SARS-CoV-2 spike protein. These lab findings suggest a potential mechanism, but this research was not conducted in humans, and its clinical relevance is still being explored.
Other compounds are examined for their anti-inflammatory and antioxidant properties. N-acetylcysteine (NAC) has been studied for its ability to interact with the spike protein, and computer simulation studies suggest it may weaken its ability to bind to ACE2 receptors. Compounds like curcumin and resveratrol are also noted for their general anti-inflammatory effects, though specific research linking them to spike protein clearance is limited.
Repurposed Drugs
Several existing drugs have been studied for repurposing. Computer models suggest ivermectin could potentially interfere with the spike protein’s ability to attach to the ACE2 receptor. However, clinical evidence supporting its use for this purpose is not established, and it is not recommended by major health organizations.
Metformin, a common diabetes medication, has also been investigated. Some research suggests taking metformin during the acute infection may reduce the later incidence of long COVID, possibly due to its anti-inflammatory effects. These avenues of research are ongoing, and none of these strategies are approved as a standard treatment for clearing spike proteins.
Mainstream Medical Approaches to Post-COVID Conditions
Given that there is no proven therapy to eliminate persistent spike proteins, the established medical approach for long COVID is centered on addressing a patient’s specific symptoms and supporting recovery. This patient-centric model focuses on improving quality of life and functional capacity through a multidisciplinary strategy.
For individuals experiencing debilitating fatigue, tailored physical and occupational therapy programs are often recommended. These programs are designed to gradually increase activity levels without causing post-exertional malaise, where symptoms worsen after physical or mental effort. Cognitive rehabilitation helps patients with ‘brain fog,’ memory loss, and concentration difficulties through targeted exercises and coping strategies.
When cardiovascular symptoms are present, such as a rapid heart rate or blood pressure fluctuations, medications may be prescribed. Patients are often referred to specialists, including cardiologists, pulmonologists, and neurologists, for individualized management plans. This approach may also include medications for pain, sleep disturbances, or mood disorders.