The immediate threat from a COVID infection is readily understood now. Most people who catch COVID-19 recover within a few weeks. However, doctors are still struggling with a different problem patients often face. Lingering, debilitating symptoms affect an estimated 6 to 10 percent of people following a COVID-19 infection. That could be as many as 16 million Americans suffering from long COVID. These “long haulers” can be disabled by fatigue and brain fog. Research presented at the Conference on Retroviruses and Opportunistic Infections (March 3-6, 2024) offered some intriguing possibilities to explain the persistent symptoms. More recent studies have also identified some markers that may help explain long COVID and offer possible treatments.
Markers Linked to Long COVID:
For years, long COVID patients have had little help for symptoms such as chronic fatigue, brain fog, trouble sleeping, shortness of breath and pain. Canadian researchers have found disruptions in the balance of immune cells in the blood of such patients. In contrast to the earlier studies you will read about below, they did not find evidence of SARS-CoV-2 virus in the blood of people afflicted with brain fog and fatigue due to long COVID (The Lancet Microbe, Oct. 25, 2024).
In addition, scientists found higher serum levels of two inflammatory proteins in people with long COVID (Frontiers in Immunology, Sep. 24, 2024). One is called galectin-9 and the other is artemin. These proteins promote inflammation and may result from increased intestinal permeability or leaky gut. The scientists suggest that treating this condition might help point toward strategies for prevention and treatment of long COVID (Journal of Autoimmunity, July 2024). We certainly hope that is true. To date, the wide range of symptoms and lack of consistent markers have been barriers to effective treatment for people who suffer greatly.
Earlier research on possible causes of long COVID is summarized below. Keep in mind that science progresses by sometimes disproving early hypotheses. That may end up being the case with the idea that the virus persists in blood to cause long COVID.
Long-Lasting Evidence of SARS-CoV-2:
Most infectious disease experts have assumed that once the body’s immune system kicks into gear, it eliminates the SARS-CoV-2 virus in fairly short order. At least that is the traditional understanding of how people get over an upper respiratory tract infections caused by influenza or cold viruses.
Old beliefs die hard. But new data from the University of California, San Francisco (UCSF) is shedding new light on the causative factors that may be contributing to long COVID.
Scientists at UCSF report the discovery of COVID-19 viral fragments in blood more than a year after infection. These antigens can be detected in some body tissues for more than two years after a bout of COVID.
People who experienced more severe infections were more likely to have lingering evidence of the virus. This research contradicts the idea that COVID is a short-term illness. There is some evidence that the virus might be holing up in connective tissue. Viral fragments were found there suggesting that the immune system was activly pursuing the pathogen wherever it was hiding.
If the SARS-Cov-2 virus is lurking in the body, how can we get rid of it? The UCSF researchers are considering monoclonal antibodies or antiviral drugs. If they can wipe out any lingering virus, perhaps we can finally get a handle on long COVID.
Muscle Problems Linked to Long COVID:
A study published in Nature Communications reveals that mitochondrial dysfunction in muscle contributes to something called post-exertional malaise (Nature Communications, Jan. 4, 2024). Mitochondria are the energy factories within cells. Many long-haulers can no longer exercise. Even modest exertion results in profound exhaustion.
Dutch scientists recruited two groups of volunteers for the study. In one group were 25 people with long COVID. In the other group were healthy people who had recovered from COVID and had no residual symptoms.
All the participants worked out for 10 to 15 minutes on stationary bikes. Muscle biopsies taken a week before the exercise session and the following day showed significant differences. The mitochondria of those with long-term symptoms were not functioning normally, and as a result, they began making lactate for exhausted muscles.
Muscles of healthy people did not need to make lactate for this short exercise bout. The biopsies also showed significant muscle damage in the people with long COVID. The researchers found evidence of autoimmune attack within these muscles. In addition, the muscles of sick volunteers had lots of microclots, especially in the post-exercise biopsy. There is as yet no proven treatment for post-exertional malaise or any of the other symptoms of long COVID. Hopefully, this research will bring doctors closer to some possible ways to ease the problems.
What Do Doctors Call Long COVID?
There are now lots of names for this condition. They include:
- Long-haul COVID
- Long COVID
- Post-Covid Syndrome (PCS)
- Post-Acute Sequelae SARS-CoV-2 (PASC)
- Post-Acute COVID-19 Syndrome (PACS)
Does Long COVID Affect Children and Teens?
Children and adolescents may be just as susceptible to long COVID as adults. At least, German scientists recently announced evidence for that (PLOS Medicine, Nov. 10, 2022). Youngsters who had a verified COVID infection were 30% more likely than uninfected kids to report symptoms such as fatigue, cough, chest pain, headache, fever, stomachache, anxiety and depression during the following year.
The authors conclude that
“Post COVID-19 syndrome cannot be dismissed among children and adolescents.”
Progress Toward Identifying Post-COVID Syndrome:
Until now, physicians had no way to identify people experiencing persistent post-COVID problems aside from the severe fatigue and brain fog that are common symptoms. Now researchers have discovered some biomarkers that set these patients apart (Nature, Sept. 25. 2023).
Blood Samples Showed Differences:
Blood samples from 268 people with long COVID showed distinct differences from those without the condition. These indicate ongoing disruption of the immune and endocrine systems. Among other indicators, the patients have lower than normal levels of cortisol, a hormone that helps us deal with stress. Some also have indications that viruses such as Epstein-Barr (the cause of mononucleosis) have reactivated.
This research has not yet changed the process of diagnosis. However, it may eventually lead to reliable blood tests and ultimately to new treatments for this condition. At this time, doctors do not have clearly proven ways to help people recover from persistent symptoms following COVID-19 infection.
An Update on Long COVID:
A study published as a preprint in MedRxiv found a high rate of persistent symptoms (MedRxiv, Sept. 6, 2022). Between June 30 and July 2, 2022, the scientists reached out to 3,042 adults by phone or text to conduct a survey in English or Spanish. Nearly 12% of unvaccinated respondents reported an infection just then. More than 28% of those with other health problems such as diabetes, obesity or high blood pressure reported infection. More young adults and Hispanics reported infections than people in other categories.
Most troubling, the researchers found that 21.5% of adults infected with the Omicron BA.5 variant last summer now battle persistent symptoms. More than four weeks after their infection, these people reported unusual fatigue, shortness of breath or trouble concentrating. Unemployed people and those with pre-existing conditions were most likely to suffer the lasting symptoms of long COVID.
With more people utilizing home COVID tests–or not testing at all, despite symptoms–public health authorities have been struggling to stay abreast of the case count. The lead author of this study says that health care authorities should start focusing more on long COVID as well as hospitalizations and deaths.
As the authors note,
“While the virus and its impact have evolved substantially, the current approaches to COVID-19 public health surveillance in the U.S. has not evolved to keep pace, making tracking of the true burden of SARS-CoV-2 increasingly challenging.”
Previous Studies of Persistent COVID Symptoms:
At least three other studies of post-COVID complications have appeared this year. The CDC reports in its Morbidity and Mortality Weekly Report (MMWR, May 27, 2022) that one in five adults between 18 and 64 years of age have persistent health problems caused by a previous COVID infection. That number is even higher among seniors. One in four people over 65 have lingering symptoms after they recover from the coronavirus.
The CDC asks this important question:
“What are the implications for public health practice?
“Implementation of COVID-19 prevention strategies, as well as routine assessment for post-COVID conditions among persons who survive COVID-19, is critical to reducing the incidence and impact of post-COVID conditions, particularly among adults aged ≥65 years.”
There is reason to be concerned. If the CDC is right that “one in five COVID-19 survivors aged 18–64 years” will experience long COVID, that could represent more than 16 million people in the US, not including senior citizens. How will health systems and insurance companies handle this second “pandemic?”
Long COVID and the Brain:
Another study published in the Annals of Clinical and Translational Neurology (May 24, 2022) shows that post-COVID symptoms often last more than a year. These researchers wanted to know more about neurological complications such as brain fog, tinnitus, numbness and tingling, fatigue, dizziness, blurred vision and headaches.
Does vaccination “cure” long-lasting symptoms? According to these authors:
“There have been media reports that vaccination cures long-COVID in some patients, but our data do not support these claims. However, these results should allay the fear of long-COVID relapse in patients reluctant to get vaccinated.”
The “interpretation” of the data from this study:
“Non-hospitalized COVID-19 ‘long haulers’ continue to experience neurologic symptoms, fatigue, and compromised quality of life 14.8 months after initial infection.’
Treating Symptoms That Linger Long After COVID:
There may now be a treatment to help ease some of the symptoms of long COVID (Scientific Reports, July 12, 2022). Israeli scientists report that hyperbaric oxygen therapy eases brain fog and some of the other symptoms such as fatigue, depression and pain.
This randomized controlled trial included 73 patients. Patients receiving active treatment got pure oxygen in a pressurized chamber. After 40 sessions, their tests demonstrated significant improvement in attention and executive function compared to untreated controls. In addition, MRI imaging showed better blood flow in the brain. Sleep, psychological symptoms such as anxiety, depression and pain also improved. Although the results are promising, the trial is small and this approach needs confirmation.
Long COVID Symptoms in Seniors:
Most studies of long COVID have not focused on specific age groups. A study of more than 130,000 Medicare Advantage patients who were diagnosed with COVID-19 shows that lingering problems are common (BMJ, Feb. 10, 2022). The researchers report in the BMJ that one-third (32 percent) of these individuals had new or persistent health problems in the four months following their recovery. As Medicare recipients, all were at least 65 years old.
The most common difficulties were trouble breathing, fatigue, high blood pressure, memory problems, kidney injury, mental health disorders, blood clots and heart rhythm disturbances. To get some perspective, the investigators compared these records to those of people who had not tested positive for COVID-19.
When they analyzed data from seniors who had viral infections of the lower respiratory tract before the pandemic, they found that people diagnosed with COVID were significantly more likely to have respiratory failure months later. Dementia and post-infection fatigue were also more common among those who had experienced COVID. Men, Black Americans and those over 75 suffered the most severe symptoms.
Tracking Long COVID Symptoms:
In the British study, the scientists used a pre-existing database including 11 million patients of primary care practices in Great Britain (JAMA Network Open, Nov. 16, 2021). Two hundred thousand of these people tested positive for SARS-CoV-2 during 2020. Follow-up surveys revealed some disturbing statistics. Previously infected people reported insomnia three times more often than those who escaped infection. Most strikingly, previously infected individuals experienced severe fatigue six times more often.
Although people also reported more anxiety and depression following infection, the researchers are not confident they can attribute that to the effects of long COVID. Individuals who’d had influenza-like illness also reported fatigue and anxiety after they recovered.
Brain and Body Both React to COVID!
An earlier study in JAMA Network Open (Oct. 22, 2021) revealed that symptoms of PACS can interfere with quality of life long after the initial infection. This research tracked 740 patients between April 2020 and May 2021. In addition to receiving care for their symptoms, these volunteers took several tests to assess their cognitive functioning.
A significant number of them had trouble with attention, memory, executive function, processing speed or language. The average age of participants was 49, and the average time since COVID diagnosis was over seven months. None had a history of dementia, despite the brain fog they were experiencing post COVID.
The authors note that younger people suffered long-lasting impairment as well as older people:
“It is well known that certain populations (eg, older adults) may be particularly susceptible to cognitive impairment after critical illness; however, in the relatively young cohort in the present study, a substantial proportion exhibited cognitive dysfunction several months after recovering from COVID-19.”
The Body Feels the Impact:
Another study included survey results from 156 people participating in a long COVID clinic (American Journal of Physical Medicine and Rehabilitation, Oct. 20, 2021). Doctors had diagnosed them with COVID-19 infection an average of a year earlier.
More than four-fifths of them reported fatigue, while two-thirds said they had brain fog and three-fifths had frequent headaches. Some also had breathing problems. They reported that their symptoms worsened after physical exertion, stress or dehydration.
The scientists concluded:
“Persistent symptoms associated with PACS appear to impact physical and cognitive function, health-related quality of life and participation in society.”
How Many People Experience Long COVID?
Earlier in the pandemic, a study by the independent, nonprofit organization FAIR Health revealed some surprising statistics. A large number of people develop new health problems 30 days or more after recovering from COVID-19 (FAIR Health White Paper, June 15, 2021). The researchers found that even people whose infections were asymptomatic might need healthcare for months or years to come.
The scientists analyzed insurance data from roughly 2 million COVID patients. All age groups reported some post-COVID symptoms. About half of those who had been hospitalized sought help for ongoing complications. Among those who reported mild infections, the proportion was still over 27 percent. One in five of those who’d had no symptoms of COVID were struggling with post-COVID syndrome. Some of these individuals may not have even realized that they had been infected months before.
Some Startling Stats:
After people survive a COVID infection and leave the hospital, they are not out of the woods.
The authors of the FAIR Health White Paper report:
“The odds of death 30 days or more after initial diagnosis with COVID-19 were 46 times higher for patients who were hospitalized with COVID-19 and discharged than patients who had not been hospitalized.”
Even people who did not need hospital care can suffer long COVID:
“Many patients recover from COVID-19 within a few weeks, but some exhibit persistent or new symptoms more than four weeks after first being diagnosed. These post-COVID conditions can last for months— even nine months, according to one study—and may be experienced by 10 to 30 percent of COVID-19 patients. The conditions can include, among others, fatigue, cognitive difficulties (sometimes called ‘brain fog’), headache, numbness/tingling, loss of smell or taste, dizziness, heart palpitations, chest pain, shortness of breath, cough, sore throat, joint or muscle pain, excessive sweating, insomnia, depression, anxiety and fever. Patients with COVID-19, after the first 30 days of illness, are at higher risk of death than people who have not had COVID-19.”
What Symptoms Are Typical of Long COVID?
Q. In March 2020, I came down with COVID-19, although at the time I thought it was just a mild case of the flu. Since then, I’ve had severe shortness of breath as well as muscle and joint aches and pains. My senses of taste and smell come and go (mostly go). I also have a dry cough and fatigue that comes on so suddenly I have to sit down immediately. I’ve had every test known to man, but nothing shows up. My biggest issue is shortness of breath.
A. Your description fits post-COVID syndrome (PCS). People with such symptoms often refer to themselves as “long haulers.” Other symptoms can include chest pain, heart palpitations, cough, brain fog and headache.
Many people now suffering PCS were not very sick initially. Despite mild to moderate COVID symptoms, they may feel profoundly debilitated months later.
Clinics are cropping up around the world to treat long COVID complications, but there are few clear answers about the best therapies. If you would like to learn more about this condition, you may wish to listen to our free podcast 1254: Combating the Long-Term Effects of Post-COVID Syndrome. You might also find Show 1230: What Happens When COVID Symptoms Don’t Go Away of interest.
Are Nervous System Problems Part of the Post COVID Picture?
Shortness of breath is not the only troublesome symptom of post-COVID syndrome. Research suggests that a significant proportion of those who recover from COVID may suffer from psychiatric or neurologic disorders.
A study published in Lancet Psychiatry found that a third of patients who had recovered from the coronavirus infection were diagnosed with a new neurological or psychiatric problem within six months (Lancet Psychiatry, April 6, 2021). The investigators reached this conclusion by analyzing the health records of more than 230,000 individuals. Depression and anxiety stood out as among the most common diagnoses.
One of the researchers remarked:
“Our results indicate that brain diseases and psychiatric disorders are more common after COVID-19 than after flu or other respiratory infections.”
Less common but more serious were strokes and dementia that occurred within six months of recovery.
This is not the first report of neurological and cognitive problems associated with COVID-19. Another study found that these are common complications of Post-COVID Syndrome (Annals of Clinical and Translational Neurology, March 23, 2021). The patients in this study were not hospitalized when they were infected, nor were they elderly. (Their average age was 43 years old.) About two-fifths had pre-existing depression or anxiety. Eighty-one percent reported “brain fog,” while 68 percent had headaches. Muscle pain and weakness, numbness and tingling, changes in the sense of smell or taste also made life difficult for many of them.
With 85 percent of these patients reporting fatigue, the researchers conclude:
“Non-hospitalized Covid-19 ‘long haulers’ experience prominent and persistent ‘brain fog’ and fatigue that affect their cognition and quality of life.”
How Common Is Long COVID?
A study published online in medRxiv (January 15, 2021) reveals some grim statistics. This article has not yet been peer reviewed. The title is:
“Epidemiology of post-COVID syndrome following hospitalisation with coronavirus: a retrospective cohort study”
The British scientists tracked 47,780 patients in the UK who left the hospital after they recovered from COVID-19. The researchers wanted to know how many of these people were readmitted to the hospital and how many died. They also tracked complications associated with the heart, lungs, kidney and liver.
The investigators introduce their research this way:
“Long COVID, or post-COVID syndrome (PCS), is not a single condition, and has been defined by the National Institute for Health and Care Excellence (NICE) as ‘signs and symptoms that develop during or following an infection consistent with COVID-19 which continue for more than 12 weeks and are not explained by an alternative diagnosis.’”
Strap In! Here Come the Results:
• “Of 47,780 individuals in hospital with COVID-19 over the study period, 29.4% were re-admitted and 12.3% died following discharge.”
• “Respiratory disease was diagnosed in 14,140 individuals (29.6%) following discharge, with 6,085 of these being new-onset cases.”
A significant number of people who “recovered” from COVID-19 went on to develop a major adverse cardiovascular event (MACE). That includes heart attack (myocardial infarction or MI), heart failure (HF), stroke and irregular heart rhythms. Other PCS complications included diabetes and chronic kidney disease.
Please note that the results of the British study from January 15, 2021 are surprisingly similar to the latest data from the FAIR Health White Paper (June 15, 2021).
The Big Picture on Post-COVID Syndrome (PCS):
We find that it is often helpful to let the investigators speak for themselves:
“In the largest study to-date to examine PCS in individuals hospitalised with COVID-19, comprising 47,780 COVID-19 cases with matched controls, we describe three major findings. Firstly, COVID-19 hospitalisation was associated with increased risk of readmission and death following discharge, relative to that in individuals of similar demographic and clinical profiles over the same period; nearly a third of people post-COVID-19 hospital discharge were re-admitted and more than 1 in 10 died.”
The authors note that the implications for the British health care system are significant. The United States health care system will also notice the effects.
Their Conclusions:
“Individuals discharged from hospital following acute COVID-19 face elevated rates of mortality, readmission and multi-organ dysfunction compared with the background levels that exist for these individuals, and the relative increase in risk is neither confined to the elderly nor uniform across ethnic groups. Urgent research is required to further understand the risk factors for PCS, so that treatment provision can be better targeted to demographically and clinically at-risk populations.”
Long Haulers Are on Their Own:
There is so much we do not understand about post-COVID Syndrome. No one knows exactly who is susceptible to it. Health professionals don’t know how to treat it. In fact, we have talked to health professionals who are themselves living with severe fatigue or other symptoms following the infection. They will tell you that it is challenging. You can hear their stories by clicking on this link.
What Happens When COVID Symptoms Don’t Go Away
Even young healthy people may have trouble when COVID symptoms don’t go away for weeks or months. Find out what it’s like.
Readers Speak Up:
Maureen wrote:
“I have two long hauler acquaintances. Both were very sick but not hospitalized. She was exceptionally active, exercised daily and is 38. The other, 68 year old male, but competed in triathlons for his age group. Both have severe issues: the woman has heart pain, neurological, taste loss and fatigue. The triathlete can barely exercise beyond 20 minutes tops. It has been about 6 months since their COVID-19 infections.”
Julia reported on her treatment regimen:
“While the scientific data might drag a bit on this issue of Vitamin D and COVID-19, I must say that, as a patient in a major university medical center’s respiratory clinic, I was recommended to take Vitamin D in a daily dosage no less than 1,000 IU @ day. I am also on a high-level Vitamin-D infused milk drink.
“I don’t have empirical data but can say that after starting this regimen, which also includes 2,000mg vitamin C, zinc picolinate 60mg; and 550 mg potassium gluconate, I am coping better with all of the effects of being a COVID-19 ‘Long Hauler.’ I’d hate to imagine what these symptoms would be like without this regimen!”
Wendy asked:
“Are there studies on those post COVID19 patients who never went to the hospital?
“I have been a long-hauler for 8 months now. At 46 years old, I needed an appendectomy while ill with COVID-19. COVID-19 was not the reason for me being in the hospital. I had many E.R. visits, though, and many, many tests done.”
If you have had experience with long COVID, please share it in the comment section below. Let us all know if you have found anything that is especially helpful.
Learn More:
A radio show/podcast on this topic discusses an experimental treatment that may be helpful against this debilitating condition. We are not endorsing this approach! It has become somewhat controversial and it could be pricey. There can be side effects. Nevertheless, we think you might find the last segment of the show interesting.
We have also discussed the issue in other podcasts. One is Show 1254: Combating the Long-Term Effects of Post-COVID Syndrome. A more recent podcast is Show 1327: What Have We Learned About Long COVID? You may find both of them interesting.
Finding a clinic or health care professional who specializes in post-infectious conditions may be challenging, but we think it is worth the effort. Not every health professional has experience with this condition. Even those who do may not have a solution. Nevertheless, it is worth seeking out people who have experience treating persistent symptoms of COVID-19.
