The Coronavirus is officially called SARS-CoV-2 (Severe Acute Respiratory Syndrome Corona Virus 2). This virus causes the disease Covid-19 (Corona Virus Disease 2019). The first SARS-CoV was the virus which causes SARS.
What does “Long Hauler” mean?
A “Long Hauler” is a person who contracted the disease Covid-19, and who continues to have symptoms many weeks later, long after most other patients have recovered. Physicians and researchers are uncertain what causes this phenomenon. Some Long Haulers have organized into support groups; others have taken part in patient-led research on the condition.
At What Point Do You Become a Long Hauler?
The condition is defined mainly by the continuation of Covid-19 symptoms long after the usual time to recovery has passed. One study found that the usual time to recovery for severe cases is 28.6 days, and for mild cases it is 11.1 days . The number of days in studies of this type will vary, but those figures are in the right range: less than 2 weeks to recovery for a mild case, and about 4 to 6 weeks to recovery for a severe case.
However, a severe case that goes on for a long time is not what is usually meant by a Long Hauler. The more typical LH case starts out as mild and doesn’t improve. It might get worse as time goes on; it might have flare ups from time to time when it is particularly bad. But it is usually not so severe as to require a single long hospitalization. Some Long Haulers are repeatedly hospitalized; this is unusual, but it fits the profile of symptoms that fluctuate in time and intensity .
“The vast majority of participants with symptoms experienced fluctuations both in the type (70% reporting) and intensity (89% reporting) of symptoms over the course of being symptomatic.” 
So a Long Hauler is someone who has had Covid-19 for more than 4 to 6 weeks, with a case that is typically mild with flare ups that can be moderate to severe. But also not so severe as to require continual hospitalization. These are persons trying to live their normal lives, at a point in time when most persons with Covid-19 would have recovered.
What Causes LongHaulers Syndrome?
A hypothesis proposed by Dr. William Petri, Professor of Medicine, University of Virginia, considers Longhaulers Syndrome to be caused by the continued presence of the SARS-CoV-2 virus (the coronavirus that causes Covid-19) in Immune Privileged Cells (IPCs). These cells include hair follicles, the Central Nervous System (CNS), the eyes, and other cells. When the virus becomes established in IPCs, the immune system cannot clear the virus, and you medications can only reach the virus in the IPCs of the CNS if it can cross the Blood-Brain Barrier. See these articles:
* The Longhaulers Hidden Virus Hypothesis
* Immune Privileged Cells affected by Longhaulers Syndrome
What Symptoms do Long Haulers have?
The “COVID-19 Prolonged Symptoms Survey” found the following symptoms to be most common [3, p. 4] on one particular patient group:
* mild shortness of breath
* mild tightness of chest
* moderate fatigue,
* mild fatigue,
* chills or sweats,
* mild body aches,
* dry cough,
* elevated temperature (98.8 to 100 F),
* mild headache,
* brain fog/concentration challenges
“Brain fog and concentration challenges were a more common symptom than cough during most weeks, as was insomnia.”  Other symptoms included loss of appetite, dizziness, insomnia, and seizures.
The above are typical symptoms of Long Haulers. But just as it true of Covid-19 cases in general, the virus attacks different organ systems in different persons, giving somewhat different sets of symptoms. Some persons have a lot of GI symptoms and others have few. Some have a lot of nervous system symptoms, and others have few. And so there is not one definitive set of symptoms that defines Long Haulers.
Long Haulers vs. Severe Cases
By comparison, a study in Italy followed patients who were discharged from the hospital after Covid-19. All these patients had to be hospitalized for Covid-19, so their cases were moderate to severe. And all the patients in this particular study survived (the study is about long term symptoms of survivors of Covid-19).
Every patient in the Italian study met the following criteria: “no fever for 3 consecutive days, improvement in other symptoms, and 2 negative test results for severe acute respiratory syndrome coronavirus 2 [SARS-CoV-2] 24 hours apart)”. Typically, such patients would be considered “cured”. They no longer have the virus detectible in their system. They have no fever and, though the study does not state this, they would have to have clear lungs (no pneumonia) to be discharged. And yet the study found that these “recovered” patients still have substantial symptoms.
At an average of 60 days after initial onset of symptoms, only “12.6% were completely free of any COVID-19–related symptom, while 32% had 1 or 2 symptoms and 55% had 3 or more” . These patients were sent home, as if they were well, and yet they had symptoms. The most common symptoms were: “fatigue (53.1%), dyspnea (43.4%), joint pain, (27.3%) and chest pain (21.7%).” Dyspnea is difficulty breathing.
Note that the Italian study was a group of hospitalized patients, in April and May, when the pandemic was particularly bad and hospitals were only accepting the most severe cases. But the typical Long Hauler is not hospitalized.
Prolonged Symptoms Survey: “Most of the respondents were not hospitalized. Many did visit the ER/urgent care to seek treatment, but they were not admitted to or stayed overnight at a hospital.” 
Another difference between the Italian group and the typical Long Hauler was the initial case — moderate to severe in the Italian study versus mild to moderate (at first) in self-described Long Haulers. To phrase the difference another way, for the Italian study the persistent symptoms represented a major improvement, whereas for the Prolonged Symptoms Survey, the continuation of symptoms often represented a worsening of symptoms.
However, symptoms were similar in both groups. The LHers have symptoms after a mild bout with Covid-19 that are comparable to the symptoms of patients who are recovering from a severe bout with Covid-19.
* Body Politic COVID-19 Support Group – a slack discussion group for Covid-19 longhaulers
* COVID-19 Survivor Corps – a Facebook public group
* Long Haul COVID Fighters – Facebook – must have been ill for more than 30 days to join
* Long Covid Support Group – Facebook
“Over half of respondents (57.8%) listed at least one pre-existing condition, with the most prevalent conditions being asthma and vitamin D deficiency. Our analyses suggest pre-existing asthma might prolong recovery time.” 
The most common co-morbidity in the Prolonged Symptoms Survey, a survey of Covid-19 Long Haulers, was asthma. This is a surprising result as some studies have shown that persons with asthma are less likely to contract Covid-19 [6, 7, 8]. But studies also show that, once a person with asthma does contract Covid-19, the outcome is much worse than for other patients .
The prevalence of asthma in the U.S. (2016 data) according to the NHANES study is 9.1%, up 1% from 2005 . In the Prolonged Symptoms Survey, the prevalence of asthma was 16.9% [3, p. 14]. That is an 85.7% increase above the background level for Covid-19 Long Haulers. This suggests that asthma patients might be more likely to develop Long Hauler condition, if they contract Covid-19.
However, an article in the journal “Allergy” noted anecdotally that asthma has been observed to be found among Covid-19 patients in lower percentages than in the general population. This was the case for a Chinese study of 140 patients which did not find any asthma among that group . The authors continue by saying:
“These findings are consistent with our observation of a low occurrence of asthmatics among admitted COVID‐19 cases (3 out of 275 individuals, one requiring ICU) in Prato (Italy), a city with 200 000 inhabitants of whom at least 10 000 are expected to be asthmatic. Further, none of the 2500 asthmatic patients referring to our Allergy Unit has been hospitalized.” 
They are following 2500 asthmatic patients, and none needed to be hospitalized for Covid-19. (They apparently did not survey the patients to see if they had Covid-19 and were at home.) The authors of that article then propose that perhaps asthma has an effect on the immune system, which protects one from Covid-19 infection. Another article surveyed 290 lab-confirmed hospitalized COVID‐19 cases, and found only one patient with asthma. 
A retrospective study of hospitalized Covid-19 patients in China  found only 5 patients with asthma out of 548. “The prevalence of asthma in patients with COVID-19 was 0.9%, markedly lower than that in the adult population of Wuhan.” 
However, a protective effect against contracting Covid-19 does not imply a protective effect after infection. Since Covid-19 affects the lungs adversely, as does asthma, it would seem that asthma patients would fare worse if they do contract Covid-19 . And that is consistent with the Prolonged Symptoms Survey.
Vitamin D Deficiency
Vitamin D deficiency was the second most common co-morbidity in the COVID-19 Prolonged Symptoms Survey, after asthma . This deficiency can be easily corrected, though not quickly, with vitamin D supplementation. Grant et al. recommend vitamin D for prophylaxis against Covid-19 and for infected persons:
“To reduce the risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D3 for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40–60 ng/mL (100–150 nmol/L). For treatment of people who become infected with COVID-19, higher vitamin D3 doses might be useful.” 
Vitamin D deficiency is a harmful condition, as it can increase risk of diseases such as cancer, cardiovascular disease, cognitive impairment in the elderly, and asthma, according to WebMD . Therefore, if only to decrease risk of other conditions and maintain the normal health of the body, vitamin D deficiency should be corrected.
Notice that vitamin D deficiency increases risk of asthma, while both asthma and vitamin D deficiency were common co-morbidities in the Prolonged Symptoms Survey. There may be a relationship between these two factors. “Vitamin D deficiency has been rediscovered as a public health problem worldwide. It has been postulated that vitamin D deficiency may explain a portion of the asthma epidemic.” 
The Prolonged Symptoms Survey asked patients whether they have taken any supplements or OTC medications. Vitamin D was one of the most common, along with zinc, vitamin C and the B vitamins. Some had taken prescription medications, such as antibiotics, cough medicine, and anti-anxiety medications.
What Causes Prolonged Symptoms?
Why do some persons have a case of Covid-19 that continues for many weeks or months? Physicians and researchers do not know. One possibility is that the virus has cleared from the person’s body, but lasting damage creates lasting symptoms. We know that Covid-19 can cause lasting damage to the lungs, in the form of scarring. In some Covid-19 cases, the virus can infect and damage neurons in the central and peripheral nervous systems. A neuron can sometimes repair itself; but if it dies, neurons do not replicate so as to replace cells destroyed by the virus.
Another possibility is that the virus remains in the body, in a constant stand-off with the immune system. Sometimes the virus temporarily gets the upper hand, causing a flare up of symptoms; then the immune system responds and the symptoms fade, only temporarily. And since the virus is not entirely cleared from the body, flare ups may recur, again and again. We know that SARS-CoV-2 has several different ways to evade and to attack the immune system (How Covid-19 Attacks your Immune System).
The third possibility, suggested by Dr. Paul Marik in this video discussion, is that the virus is gone and inflammatory response won’t turn off. He recommends medical intervention, not self-treatment. See the video link here. And see the MATH+ protocol by Dr. Marik here.
* Chua, Robert Lorenz, et al. “COVID-19 severity correlates with airway epithelium–immune cell interactions identified by single-cell analysis.” Nature Biotechnology (2020): 1-10. — This study suggests that continued symptoms of Covid-19, after viral clearance, could be due to a continuation of a hyperactive immune system, resulting in inflammation. Reducing inflammation would then be the key to stopping the symptoms of long haulers. This agrees with what Dr. Marik suggested.
The Phosp-Covid Study (phosp.org) will examine long-term consequences of Covid-19.
“The Post-hospitalisation COVID-19 study (PHOSP-COVID) is a consortium of leading researchers and clinicians from across the UK working together to understand and improve long-term health outcomes for patients who have been in hospital with confirmed or suspected COVID-19.”
This study is not solely aimed at understanding the Long Hauler condition. It more broadly covers the effects of Covid-19, even in patients who seem to have recovered completely. Since this is a new disease, we lack information on its long- or even medium-term effects.
Further research is needed on the Long Hauler phenomenon. In particular, we need to know what cases the condition, and why some persons are affected and others are not. It is also important to discover which treatments will resolve the condition and bring the long tail of symptoms to an end.
Ronald L. Conte Jr.
Note: the author of this article is not a doctor, nurse, or healthcare provider.
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