Even though it has been six years since the COVID-19 pandemic first disrupted our lives, millions of people are still fighting a quiet, lingering battle with the virus. A June 2026 study from Mass General Brigham, published in JAMA Network Open, reveals that the true scale of long COVID is much larger than anyone realized. By using advanced AI to comb through nearly 460,000 health records, researchers discovered that an estimated 10 million people are likely suffering from chronic post-viral illness without ever receiving an official diagnosis.
Why are so many cases are slipping through the cracks? The short answer comes down to the fragmented nature of modern healthcare. When a patient schedules an appointment to complain about persistent fatigue or aching joints months after clearing an infection, doctors often treat those individual symptoms separately, rather than connecting the dots to the actual root cause.
While the intense, acute waves of the virus are thankfully behind us, this steady rise in chronic conditions has evolved into a major public health hurdle that seriously impacts everyday quality of life. To help make sense of it all, let’s dive into the science behind how this multisystem disorder works and look at some practical ways to manage its symptoms.
What is long COVID?
Long COVID, commonly referred to as post-acute sequelae of COVID-19 (PASC), is a debilitating, multi-system illness characterized by health impacts and physical symptoms that last or develop at least three months after an initial COVID-19 infection, a PMC publication explains. It is not like the normal seasonal cold or flu, which patients recover from in a few weeks; it turns an acute viral infection into a chronic disorder.
Dr. Justus Rabach, MD, MD, tells Blavity Health, “The symptoms of long COVID are so elusive that there is no single clinical pathway by which it manifests. Symptoms are reported to be more than 200. They can vary from one day to the next, such as extreme neurological fatigue, mental fog, chronic shortness of breath, heart palpitations and gastrointestinal upset.”
It is similar to other poorly understood post-infectious syndromes like chronic Lyme disease and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) that can ensnare patients in a vicious cycle of recurring poor health for years.
What’s happening in your body
Long COVID is not some imagined or purely psychological illness: it is a serious condition. This medical disorder affects several major organ systems at once, and can be measured. Peer-reviewed pathological research monitored by the National Institutes of Health (NIH) indicates that the virus can cause a low-grade systemic inflammatory state that does not resolve after the acute phase of the illness. This continued immune activation results in the body’s defense mechanisms attacking healthy tissues.
The inflammatory response is harmful and injures the fragile inner lining of your blood vessels, leading to the formation of microscopic blood clots (microclots). These microclots block small capillaries, preventing oxygen and essential nutrients from reaching the brain’s muscles and tissues effectively. At the cellular level, chronic inflammation interferes with mitochondria (the powerhouses of your cells).
This is why patients experience post-exertional malaise (PEM), a dramatic drop in physical and mental energy after a small amount of everyday activity. Vagus nerve dysfunction (dysautonomia) is also commonly present and can result in increased or decreased heart rate, as well as sudden dizziness upon standing.
Causes of long COVID
Medical scientists are examining several major biological pathways that seem to underlie the persistent symptoms of post-acute sequelae. The most popular theory is that viral reservoirs exist: that is, segments of active viral RNA or proteins persist in latent form in tissues such as the gut or nervous system and constantly challenge the immune system.
The Mayo Clinic says there is a second major cause: the development of an autoimmune response in which the confused immune system produces autoantibodies that attack the body’s own healthy nerve and vascular cells. Further, the first viral stressor can reactivate many common latent viruses within the patient’s own system, which produce a widespread and intense chronic fatigue and joint inflammatory response, such as Epstein-Barr virus (EBV).
Health risks and complications
Uncontrolled long-term post-viral symptoms present unique health risks beyond mere exhaustion; they often develop into cardiovascular and neurological ones.
A comprehensive 2026 epidemiological report from The Lancet found that patients with long COVID are at an increased risk of developing new-onset cardiovascular conditions. These conditions include myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the heart’s outer lining), as well as dangerous cardiac arrhythmias.
Underlying mechanisms include chronic microvascular inflammation, increasing the stiffness of arterial walls over time, which increases the risk of hypertension and long-term risk of stroke.
In addition, the nature of the disease can be confusing, and medical professionals often misdiagnose the patient with a primary psychiatric disorder, thereby attributing the physical symptoms to uncomplicated anxiety.
What to do about long COVID
There is no single diagnostic laboratory test for long COVID and no universal cure, so at this time, medical management is aimed solely at reducing symptoms and preventing the depletion of remaining energy reserves.
Pacing is key to clinical recovery, and it involves carefully planning your day’s activities so you move at your body’s energy level. It is not possible to “push through” severe exhaustion, and it will add to your baseline, leading to post-exertional malaise. Patients should break up large tasks into smaller ones, schedule rest periods throughout the day, and, of course, avoid high-intensity cardiovascular exercise, which causes a systemic inflammatory crash.
Doctors may also recommend increased fluid intake and electrolyte-rich foods in your daily diet, as well as the use of graduated compression garments to promote normal blood flow and address specific problems, such as dysautonomia.
If you want to avoid major energy crashes, start keeping a daily activity and symptom log on your phone. Record how many hours you spend standing, typing or walking, and report any physical crashes that you experience 24 to 48 hours later. Once you determine your own energy limit, you’ll be able to find the perfect rhythm and pace for your body without causing your immune system to become unstable and your symptoms to worsen.
Who is more prone to long COVID?
Most people can get long-term illness from the virus, but certain groups of people are more likely to develop the condition and have a higher baseline risk.
Like many autoimmune diseases, women are more likely to develop long COVID than men, according to the CDC. Furthermore, people with certain health issues, including pre-existing diabetes, serious asthma or predispositions to autoimmune diseases, are more likely to experience longer symptoms.
Most importantly, there is clinical evidence that people who were never given a primary course of the protective vaccine are at significantly increased risk of developing long-term post-viral complications after an acute infection.
What vitamins are good for post-COVID fatigue?
Although vitamin supplements will not fix the dysfunction of the cells, some micronutrients can help maximize your energy output from your mitochondria and reduce systemic inflammation during recovery.
Nutritional research studies published by the NIH indicate that supplementation with Coenzyme Q10 (CoQ10) and Alpha-Lipoic Acid (ALA) can support cellular energy systems and help compromised mitochondria produce ATP more efficiently. In addition, ensuring optimal levels of Vitamin D3 and Omega-3 fatty acids is strongly recommended for general immune system regulation and to suppress chronic vascular swelling.
Before adding high-dose supplements to a post-viral recovery program, always discuss with the primary health care provider to confirm blood levels.
When to see a doctor
If you have physical or cognitive symptoms that persist for more than 12 weeks after an infection, make an appointment with your primary care provider or a post-COVID recovery center.
If you have suddenly developed crushing chest pain, a dangerously fast heart rate that won’t slow down when you rest, extreme shortness of breath or suddenly slurred speech, it’s time to seek emergency medical care. Since the diagnosis is based solely on symptoms, other treatable causes of these symptoms, such as anemia, thyroid failure or an autoimmune exacerbation, need to be excluded.
“The burden of these new chronic diseases is accumulating,” Hossein Estiri, PhD, an author of the study and leader of MGB’s clinical augmented intelligence research group, says. “It is a compounding crisis.” The best way to protect your health in the long run is to stand up for yourself and work with a doctor who is willing to listen and understand.
Bottom line
An estimated 10 million Americans have long COVID, a multi-system medical condition caused by chronic inflammation, microvascular clotting and mitochondrial damage that remains undiagnosed. Patients experience a variety of symptoms that recur over time, such as fatigue, brain fog and dizziness. It’s crucial to use careful pacing of activity rather than pushing too much exercise to avoid permanent crashes. With the assistance of specialists, by understanding inner triggers and by implementing focused supportive treatments, people can effectively manage their post-viral recovery and naturally sustain wellness in the long run.
Frequently Asked Questions
Does long COVID ever go away?
While many patients experience a slow, gradual improvement in their symptoms over several months or years of careful pacing, others navigate a fluctuating, relapsing course of chronic illness that currently lacks a definitive medical cure.
What does long COVID do to your heart?
Long COVID can trigger chronic inflammation of the heart muscles and blood vessels, leading to microclots, sudden heart palpitations, unmanaged chest pain and an elevated long-term statistical risk for developing dangerous arrhythmias or heart failure.
Citations
Parums DV. Long COVID or Post-Acute Sequelae of SARS-CoV-2 Infection (PASC) and the Urgent Need to Identify Diagnostic Biomarkers and Risk Factors. Medical Science Monitor. 2024;30. doi:https://doi.org/10.12659/msm.946512
Bai N, Richardson C. Posttreatment Lyme disease syndrome and myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review and comparison of pathogenesis. Chronic Diseases and Translational Medicine. Published online June 11, 2023. doi:https://doi.org/10.1002/cdt3.74
Davis HE, McCorkell L, Vogel JM, Topol EJ. Long COVID: major findings, mechanisms and recommendations. Nature Reviews Microbiology. 2023;21(3):1-14. doi:https://doi.org/10.1038/s41579-022-00846-2
Mayo clinic. Lupus – Symptoms and Causes. Mayo Clinic. Published October 21, 2022. https://www.mayoclinic.org/diseases-conditions/lupus/symptoms-causes/syc-20365789
Lindberg P, Wiqvist S, Juszczyk M, et al. Long COVID and risk of incident cardiovascular disease: a prospective cohort study using the Multimorbidity Integrated Registry Across Care Levels in Stockholm (MIRACLE-S) cohort. eClinicalMedicine. Published online April 2026:103846. doi:https://doi.org/10.1016/j.eclinm.2026.103846
CDC. Products – Data Briefs – Number 480 – September 2023. www.cdc.gov. Published September 22, 2023. https://www.cdc.gov/nchs/products/databriefs/db480.htm
Tippairote T, Bjørklund G, Gasmi A, et al. Combined Supplementation of Coenzyme Q10 and Other Nutrients in Specific Medical Conditions. Nutrients. 2022;14(20):4383. doi:https://doi.org/10.3390/nu14204383