Long Covid describes a collection of lingering symptoms devastating the lives of many COVID-19 survivors.
“Post COVID-19 condition occurs in individuals with a history of probable or confirmed SARS-CoV-2 infection, usually 3 months from the onset of COVID-19 with symptoms that last for at least 2 months and cannot be explained by an alternative diagnosis.”
— The World Health Organization (WHO)
The most frequent prolonged symptoms are persistent fatigue, brain fog, and depleted energy after even a minimal effort — having a profound impact on everyday functioning. The WHO estimates that 10% to 20% of COVID-19 patients experience lingering symptoms for months following infection. Researchers anticipate that many patients will have this disease for their lifetime.
Long Covid is also known as Post-COVID syndrome, Long Haulers, Long-term COVID-19, Post-Acute COVID Syndrome (PACS) or LTC-19.
These terms describe a collection of lingering symptoms:
Preliminary reports and data about Long COVID symptoms and patient experiences contain many similarities to other chronic illnesses known to be associated with viral triggers, such as: Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), postural orthostatic tachycardia syndrome (POTS), other forms of dysautonomia, and Mast Cell Activation Syndrome (MCAS), just to name a few.
Myalgic encephalomyelitis (ME), previously called chronic fatigue syndrome (CFS), is a complex and debilitating multi-system, chronic disease often associated with viral infections. While “ME/CFS” is the preferred name by many, this disease has also been called systemic exertion intolerance disorder (SEID), chronic fatigue immune deficiency syndrome (CFIDS), or post-viral fatigue syndrome (PVFS).
“Post-exertional malaise” (PEM) is a hallmark of ME/CFS. PEM is the worsening of symptoms, fatigue, and discomfort following exertion. PEM occurs when even mild exertion or normal activity results in the loss of physical and mental stamina, as well as the worsening of other symptoms after exertion. Post-exertional malaise can sometimes occur immediately but is generally delayed for 24 or more hours following exertion.
A report found between 836,000 and 2.5 million people in the United States suffer from ME/CFS, and up to 80 percent of cases of ME/CFS are initiated by an infection, such as COVID-19. At this time, the cause of ME/CFS is not fully understood. There is no diagnostic test, no FDA-approved treatment, and patients often suffer for life.
There is emerging evidence that many individuals who contract COVID-19 are suffering with persistent symptoms that are reminiscent of ME/CFS. These cases of extended illness following COVID-19 are being called “Long Term COVID-19” or “Long Covid.” Additionally, expert ME/CFS clinicians have reported diagnosing a growing number of patients with ME/CFS following a COVID-19 infection.
About 80% of people with ME/CFS report that their symptoms followed a viral infection and research shows that previous coronaviruses (SARS and MERS) triggered ME/CFS in about 11% of patients. One 2009 study of SARS patients reported that 40% of patients continued to experience ME/CFS-like symptoms four years after their initial viral infection. If the novel coronavirus behaves like SARS and MERS in regards to lasting ME/CFS symptoms, as early evidence suggests is likely, COVID-19 could potentially double the existing number of patients with ME/CFS in the United States over the next two to four years.
 Evengård B, Jonzon E, Sandberg A, Theorell T, Lindh G. Differences between patients with chronic fatigue syndrome and with chronic fatigue at an infectious disease clinic in Stockholm, Sweden. Psychiatry Clin Neurosci. 2003 Aug;57(4):361-8. doi: 10.1046/j.1440-1819.2003.01132.x. PMID: 12839515.
 Hickie I, Davenport T, Wakefield D, Vollmer-Conna U, Cameron B, Vernon SD, Reeves WC, Lloyd A; Dubbo Infection Outcomes Study Group. Post-infective and chronic fatigue syndromes precipitated by viral and non-viral pathogens: prospective cohort study. BMJ. 2006 Sep 16;333(7568):575. doi: 10.1136/bmj.38933.585764.AE. Epub 2006 Sep 1. PMID: 16950834; PMCID: PMC1569956.
 Lam MH, Wing YK, Yu MW, Leung CM, Ma RC, Kong AP, So WY, Fong SY, Lam SP. Mental morbidities and chronic fatigue in severe acute respiratory syndrome survivors: long-term follow-up. Arch Intern Med. 2009 Dec 14;169(22):2142-7. doi: 10.1001/archinternmed.2009.384. PMID: 20008700.
While there are still many open questions, the ME/CFS community is here for you as a resource ready to share its experience.
Many studies and reports from people with ME/CFS show that exercise or intense exertion at the early stages of illness leads to significantly worse long-term health outcomes and potential disability.
“Pacing refers to spacing out your activities during the day so that you’re able to stay within the limits of what your body can handle without exacerbating your symptoms. Another way to think of it is that pacing is a way to keep you inside your ‘energy envelope’—the envelope that contains your energy stores for any given day.”
— Toni Bernhard J.D., Pacing: The Chronically Ill Person’s Best Friend
Visit our patient resources page for information about finding a doctor, securing a personal support system, tracking symptoms, and more.
The You + ME Registry + Biobank is a collection of patient-reported data and biological samples (e.g. blood) from people living with ME/CFS, people with Long Covid, and healthy volunteers. Our large, rich dataset is used by researchers searching for treatments and a cure. Help uncover causes and identify treatments for ME/CFS, Long Covid, and other post-viral illnesses.
Visit the Long COVID Alliance for a list of studies, clinical trials, and research opportunities.
Check out the COVID-19 and ME/CFS Webinar playlist on our YouTube page.