Millions Don’t Regain Senses of Smell and Taste After COVID: Clinicians Share Validated Approaches

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Out of the 36 million Americans who contracted COVID-19 in 2021, an estimated 800,000 didn’t regain their sense of smell, and 540,000 didn’t regain their sense of taste after recovering from the infection, according to a recent study published in The Laryngoscope.

The study’s data further suggest that many more people experienced only partial recovery in their taste or smell post-infection—5.2 million and 4.2 million, respectively.

“Losing your sense of smell or taste isn’t as benign as you may think,” Dr. Neil Bhattacharya, a professor of otolaryngology at Mass Eye and Ear and the senior author of the study, said in a statement. “It can lead to decreased eating for pleasure and, in more extreme cases, it can lead to depression and weight loss.”

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Sense of smell is intricately connected to emotions and memories, providing individuals with a sense of security that is often taken for granted. It enables the detection of spoiled food, smoke, and other environmental chemicals. Furthermore, the senses of smell and taste play a crucial role in the enjoyment of food.

Although most people regain their sense of smell upon recovery from COVID-19, some may experience persistent symptoms. Notably, even vaccinated people have reported persistent symptoms following COVID-19 vaccination.

Loss of Smell and Taste: Long COVID Versus Vaccine Injury

Reports have indicated anosmia (loss of smell) and ageusia (loss of taste) following COVID-19 vaccination. The Vaccine Adverse Event Reporting System has received more than 5,000 cases of anosmia and more than 6,000 cases of ageusia (pdf).

There have also been numerous reports of parosmia (distorted sense of smell) and taste disorders after vaccination.

Although the symptoms may appear similar, the underlying mechanisms might differ, according to Dr. Jeffrey Nordella, a family physician.

In long-COVID patients, smell and taste impairment is frequently associated with damage to the cells responsible for detecting smells that occurs during the acute stage of COVID-19.

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COVID-19 mRNA vaccines deliver lipid nanoparticles into the arm muscle and bloodstream. These lipid-coated nanoparticles can enter cells more efficiently than the COVID-19 virus. Once inside cells, mRNA molecules instruct the cells to produce spike proteins. The released spike proteins can trigger inflammatory and oxidative stresses in nearby cells and tissues, potentially contributing to long-COVID symptoms and vaccine-related effects.

A new study in 2022 found that a neutrophil-associated cationic protein contained in saliva can prevent COVID-19 infection. This image shows a 3D print of a spike protein of SARS-CoV-2—the virus that causes COVID-19—in front of a 3D print of a SARS-CoV-2 virus particle. Courtesy of NIAID/RML

Why Do Some Patients Lose Their Senses of Smell and Taste?

Loss of smell and taste due to COVID-19 is usually not complete but manifests as a muted or distorted sensory experience.

Patients may also develop parosmia, which can cause appealing flavors to turn foul, and hyposmia, a muted sense of smell.

Damaged Sensory Cells and Nerves

The primary cause of loss of smell and taste in COVID-19 patients is the direct effect of the virus on the cells and tissues responsible for these senses. The SARS-CoV-2 virus can invade and damage the olfactory epithelium, which contains the specialized cells responsible for detecting smells. This damage can disrupt the signaling process and lead to a loss or alteration of smell and taste perception.

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The connection between smell and taste is strong, as they are processed together in the brain. The impairment of these senses is predominantly associated with issues in the olfactory system because smell is responsible for about 80 percent of taste experience.

“I’ve had patients come in [who] can’t smell, but they can taste, and vice versa,” Dr. Nordella said. “It’s not an all-or-none [situation]. Nerves can be recruited ... so they might have a diminished taste, but they can taste things.”

Chronic Inflammation

Inflammation of the nasal and oral cavities has been associated with potential impairments in smell and taste perception, and it’s known that both the COVID-19 virus and its spike proteins can induce inflammatory responses.

During acute viral infection, there is a risk of excessive cytokine release, known as cytokine storms, which can have severe consequences. Additionally, studies have indicated that spike proteins can activate oxidative pathways and induce cellular stress.

Blood Clot Formation

Some research suggests a potential association between spike proteins—whether from the COVID-19 virus or the vaccine—and blood clot formation, resulting in impaired or blocked smell and taste pathways.

ACE-2 receptors, which spike proteins use to infect and damage cells, are common to endothelial cells that line the inner blood vessels. Studies have shown that spike proteins alone can damage and impair endothelial function, causing inflammation in the inner lining, also known as endotheliitis. Other studies have suggested that endotheliitis promotes blood clot formation.

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While microclotting is also observed in other chronic conditions, such as diabetes and Parkinson’s disease, the clots generated by these spike proteins tend to be larger and more resistant to breakdown, according to Etheresia Pretorius, a scientist and professor in physiological sciences at Stellenbosch University, South Africa.

Microclots may block blood flow to the nerves responsible for detecting smell and taste, which could result in damage or dysfunction. If these clots develop near the olfactory and gustatory systems, they may adversely affect the senses.

Treatment Options to Regain Senses of Smell and Taste

Anti-Parasitic Drug Ivermectin

Ivermectin has emerged as a prominent first-line treatment for both long-COVID- and vaccine-related symptoms, demonstrating its effectiveness in clinical practice.

Dr. Pierre Kory, a critical care pulmonary specialist, has observed notable improvements in approximately 70 to 80 percent of his patients upon administering ivermectin. Some patients experience a restoration of their senses of smell and taste despite that the drug isn’t prescribed explicitly for those symptoms.

Ivermectin suppresses proinflammatory pathways, impeding the production of inflammatory substances, and modulates the immune system to restore a balanced ratio between inflammatory and anti-inflammatory agents.

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A 2022 comprehensive analysis demonstrated that ivermectin fulfills at least 20 roles in preventing COVID-19 infection and mitigating viral damage. Ivermectin exhibits the potential to bind to spike proteins and COVID-19 viruses, aiding in their clearance. It also contributes to cellular well-being by facilitating energy production, even in challenging circumstances.

Low-Dose Naltrexone

Naltrexone is commonly prescribed as a medication to address alcohol and opioid abuse. However, when administered in lower doses, usually ranging from 1 to 5 milligrams per pill, naltrexone exhibits anti-inflammatory and immunomodulatory properties.

It has been theorized that low-dose naltrexone modulates the balance between inflammatory and anti-inflammatory cells and processes. The drug elevates anti-inflammatory processes in highly inflammatory states while suppressing inflammatory pathways.

Before low-dose naltrexone’s application in long-COVID and vaccine injury, clinicians used it off-label to treat fibromyalgia, Crohn’s disease, and multiple sclerosis.

In the context of managing long-COVID- and vaccine-related injuries, doctors such as board-certified internist Dr. Keith Berkowitz and neurologist Dr. Diane Counce have found that naltrexone shows promise in treating neuroinflammation and neuropathies, which may be associated with problems related to smell and taste.

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Naltrexone has been found to decrease the release of inflammatory substances commonly seen in severe and prolonged cases of COVID-19, thereby helping to alleviate these particular symptoms.

Omega-3 Fatty Acids

Alabama-based Dr. Counce and nurse practitioner Scott Marsland have reported successful outcomes in restoring patients’ senses of smell and taste by using omega-3 fatty acids.

Mr. Marsland, who shares a private practice with Dr. Kory at the Leading Edge Clinic, follows a gradual approach, initially starting patients on a weekly dosage of 1 gram of omega-3 fatty acids and gradually increasing it over the weeks to 4 grams per day. According to his observations, this protocol has contributed to improvements in smell and taste.

Omega-3 fatty acids are essential components of cell membranes and possess anti-inflammatory properties, facilitating the body’s engagement with anti-inflammatory pathways. Notably, they exhibit a protective effect on neurons and help prevent damage to blood vessels.

Early studies on acute COVID-19 cases have indicated that patients who experienced more severe symptoms tended to exhibit lower levels of omega-3 fatty acids, suggesting that adequate intake of these acids might offer protection against exacerbated symptoms.

Despite its benefits, Mr. Marsland cautions that high omega-3 fatty acid supplementation doses may lead to cardiac symptoms. Studies have linked omega-3 supplementation with atrial fibrillation.

Anti-Clotting Therapies

Many of Dr. Counce’s patients have reported improvements in their senses of smell and taste after starting triple therapy to reduce blood clotting.

This therapy usually includes the anticoagulant apixaban, which helps prevent the formation of blood clots, along with anti-platelet medications such as clopidogrel and aspirin. Clopidogrel and aspirin work by inhibiting platelet aggregation, thereby reducing the risk of clot formation.

In some cases, Dr. Counce may also consider prescribing dietary supplements such as nattokinase, derived from fermented soybeans, and serrapeptase, derived from silkworms.

Apart from its anticoagulant properties, nattokinase has been investigated in a Japanese study for its potential to degrade spike proteins. Since spike proteins are implicated in the development of abnormal blood clots associated with long-COVID- and vaccine-related injuries, the additional effect of nattokinase may explain why it’s sometimes perceived as beneficial in addressing clotting issues.

Mr. Marsland intentionally prescribes a higher dosage of nattokinase twice daily to patients experiencing loss of smell and taste. This supplement can effectively aid in the breakdown of blood clots that obstruct the nerves from receiving adequate oxygen and nutrients.

However, patients with underlying mast cell problems, soy allergies, and other hypersensitivities may report intolerance to nattokinase, Mr. Marsland said.

A bowl of fermented soybeans, also known as natto. Nattokinase is derived from this Japanese dish. Shutterstock

Other Therapies to Consider

Smell retraining is a commonly employed therapy for patients with smell and taste disorders. Dr. Counce shared one example involving a patient who successfully regained her sense of smell through the use of essential oil kits for nasal training.

In cases in which smell and taste symptoms are milder, supplements may offer some benefits. Dr. Counce suggests considering vitamin D and B12 supplements because deficiencies in these vitamins are relatively common and correcting such deficiencies may resolve sensory problems.

Dr. Nordella and Dr. Counce both also recommended zinc as a basic supplement for treatment.

During an infection, the body’s zinc storages become depleted, and this deficiency is often linked with a loss of smell and taste. The exact mechanism behind zinc deficiency’s effect on the sense of smell and taste remains unknown.

Dr. Berkowitz said he believes that loss of smell and taste could be linked to excessive levels of histamines resulting from mast cell activation. Histamines have the potential to cause neuroinflammation and neuronal damage.

Studies have shown that histamine can activate microglial cells, which act as inflammatory immune cells and may harm neurons.

Considering the possibility of underlying histamine issues in many of his patients, Dr. Berkowitz often starts them on a combination of antihistamines and other drugs. While some patients report improvements in their senses of smell and taste, it remains uncertain whether the effect can be primarily attributed to antihistamines or other medications, such as low-dose naltrexone.

Research suggests that antihistamines improve anosmia and ageusia. Patients with congested sinuses and sinusitis might experience symptom relief from antihistamine usage.

Injection of Local Anesthetic

A stellate ganglion block is a more invasive treatment option for long-COVID and vaccine injuries.

This involves injecting a fast-acting anesthetic into the stellate ganglia, clusters of nerves located on each side of the neck. This procedure temporarily calms the overactive sympathetic nervous system associated with dysautonomia, characterized by chronic hyperactivation.

“We’re blocking the nerves in the neck that control that fight-or-flight response,” Joshua Dunlap, board-certified in nonsurgical pain management at Republic Pain Specialists, a clinic that has treated more than 1,700 patients suffering from post-COVID symptoms, told The Epoch Times. “A lot of these symptoms get better, and some just completely go away,” he said.

While many patients have reported immediate improvements in symptoms such as fatigue, shortness of breath, and loss of taste and smell, the evidence supporting the effectiveness of stellate ganglion block is mainly anecdotal. Different clinics use varying types of anesthetics, which could affect the success rate.

A stellate ganglion procedure performed at Joy Wellness Partners. Rafa Cuadras

A study published in May 2023 examined the effect of stellate ganglion block on 195 long-COVID patients at Mr. Dunlap’s clinic. The authors found that 87.4 percent of the participants reported an enhanced sense of smell after receiving the injection.

Mr. Dunlap observed that some patients show immediate response to treatment, while others experience a gradual recovery.

Some patients have symptom flare-ups, often associated with high levels of stress and trauma. Building resilience to stress helps prevent reactivation.

For example, cold showers and practicing Wim Hof breathing have been clinically proven to reduce stress.

Not all individuals are suitable candidates for this therapy. Allergies to the anesthetics or pregnancy, among other things, may affect its efficacy or be contraindicated.