A tired person with his hands on his head

Long COVID shares many key similarities with Post Intensive Care Syndrome (PICS), but one main difference is that Long COVID can impact people who were never severely ill or hospitalized. Disturbingly, many people with mild or no symptoms during their initial COVID infection may develop ongoing symptoms afterward and even become chronically disabled.

Similar to PICS, some people who were profoundly ill with acute COVID do not report any ongoing symptoms after their initial recovery and we do not yet understand why that is. Additionally, some patients that were hospitalized can have symptoms of both PICS and Long COVID, suggesting they may have similar but distinct mechanisms.

Although prevalence estimates vary widely, the Centers for Disease Control and Prevention (CDC) results of the Household Pulse Survey from November conservatively estimated that 14.6% of all adults report ever experiencing Long COVID (Long COVID - Household Pulse Survey - COVID-19 (cdc.gov).

This percentage may seem small overall, but when the total number of people is very large, even a small percentage can translate to a gigantic number. In this example, the number of people would be equal to more than the population of New York City and Los Angeles combined. 

Long COVID is a broad term that includes signs, symptoms, and conditions that continue or develop after initial COVID-19 or SARS-CoV-2 infection.

Doctor with their patient


  • To meet the World Health Organization’s definition of Long COVID, someone should have continuation or development of new symptoms 3 months after the initial SARS-CoV-2 infection, with these symptoms lasting for at least 2 months with no other explanation (Long COVID definition).

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.

Common symptoms include fatigue, shortness of breath, cognitive dysfunction but also others, which generally have an impact on everyday function. Symptoms may be new onset, following initial recovery from an acute COVID-19 episode, or persist from the initial illness. Symptoms may also fluctuate or relapse over time.

Importantly, severe and life-threatening medical events can occur months or years after your initial infection, including heart attack, stroke, and new onset diabetes. 

Because Long COVID is an umbrella term for many different presentations and symptoms after acute infection, it is likely that there are multiple potential biological pathways occurring, that are not mutually exclusive.

Many patients also meet criteria for other diagnoses, including:

  • Mild Cognitive Impairment (MCI) or more pronounced neuropsychological dysfunction that in some patients falls under the term "Alzheimer's Disease and Related Dementias" (ADRD). Read more here:
    The Haunting Brain Science of Long COVID
  • Autonomic Nervous System Dysfunction
  • Postural Orthostatic Tachycardia Syndrome (POTS)
  • Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS)
  • Immune System Dysfunction

This becomes more complex with patients that have pre-existing conditions. Right now, scientists and clinicians are still teasing out these overlapping conditions, potential causes, as well as different sets of risk factors and outcomes.

We highly recommend reading the most recent review by Davis et al for symptoms and risk factors:

Long COVID: major findings, mechanisms and recommendations | Nature Reviews Microbiology

Below is a list of common symptoms of Long COVID; however, symptom presentation and severity can vary and include symptoms not listed below. Some have experienced symptoms that go undetected by normal clinical evaluations, and as a result many patients go without a diagnosis or appropriate care.

General symptoms

  • Tiredness or fatigue that interferes with daily life
  • Symptoms that get worse after physical or mental effort (also known as “post-exertional malaise”)
  • Fever

Respiratory and heart symptoms

  • Difficulty breathing or shortness of breath
  • Cough
  • Chest pain
  • Fast-beating or pounding heart (also known as heart palpitations)

Neurological symptoms

  • Cognitive impairment (sometimes known as “brain fog,” though patients say this term grossly under-describes what is experienced), which involves problems with attention/concentration, executive functioning, memory, language, processing speed, and visuo-spatial ability. This effectively qualifies, in many people, as a form of mild to moderate cognitive impairment and in some patients meets the definition of a rapidly-acquired dementia. It can last months and in some cases even years.
  • Headaches
  • Sleep problems
  • Dizziness when you stand up (lightheadedness)
  • 'Pins-and-needles' feelings
  • Change in smell or taste
  • Light and sound sensitivity
  • Depression or anxiety
  • Ringing in the Ears (tinnitus) and new onset stuttering speech

Digestive symptoms

  • Diarrhea
  • Stomach pain

Other symptoms

  • Anxiety, depression, and/or PTSD
  • Joint or muscle pain
  • Rash
  • Changes in menstrual cycles
Man looks out the window

Cognitive Functioning and Mental Health

At the CIBS Center, our primary focus is on cognitive and mental health symptoms that are experienced by individuals with Long COVID.

In the cognitive arena, symptoms are often referred to as “brain fog.” Many have noted, however, that a more accurate term may be “brain injury” as “brain fog” may not capture the severity and the degree of disruption these symptoms pose. Developing abruptly during COVID, regardless of COVID severity, these symptoms include difficulties in attention, executive functioning, memory, and processing speed (described in detail in our page on Post Intensive Care Syndrome).

These are not “academic” or “abstract” problems – instead they are very practical, as they contribute to daily difficulties in almost every area of life and are especially impactful at school and at work, while also affecting daily functioning on tasks like cooking and driving and managing medications, to name just a few.

In some cases, the cognitive problems experienced by those living with Long COVID may worsen and, essentially, convert to dementia (particularly in patients who are relatively older), although for most people they will remain stable even if untreated. Numerous studies are exploring the benefits of cognitive rehabilitation and brain training for COVID related brain fog, and this is a promising avenue, although rehabilitation should not be attempted without consultation with your physician.

With regard to mental health symptoms, these mainly include anxiety, depression, PTSD, and sometimes, OCD.  In some cases, these problems develop with little or no warning and often develop in response to the personal difficulties that COVID has caused. For individuals already experiencing these mental health issues prior to contracting COVID, they often get worse.  

The estimated prevalence of mental health conditions during Long COVID vary widely across literally dozens of studies but in general, depression and anxiety are thought to occur in up to a third of COVID “Long Haulers.”  PTSD is somewhat less common but, in some cases, can be very severe.  

A wide range of empirically validated (that is, effective) treatments have been developed for all these conditions.  In our experience with patients and families, these treatments—often relying on methods like cognitive behavior therapy, cognitive processing therapy, and prolonged exposure—can be highly effective. These and other treatments are widely available, especially with the increased use of telehealth. Discussing these options with your provider can be a good first step toward receiving treatment.

Risk Factors

The following have been identified as potential risk factors connected to developing Long COVID. 

COVID Vaccine

Not receiving the COVID vaccine is a risk factor for Long COVID, as most data indicate a reduction in Long COVID risk in people who have received the vaccine. In rare circumstances people can develop adverse immunological reactions to the COVID vaccination (e.g., myocarditis), but such problems are way more common after COVID than vaccine injury. There are no large, well-done cohort studies showing that the vaccine causes Long COVID, and certainly the best way to prevent Long COVID is to do whatever is available to prevent getting COVID in the first place.

Here are some references of interest:

In this study, authors found six studies of 17M people that when analyzed together showed vaccination was associated with a reduction in the risk of Long COVID, with two doses better than one dose. Overall 17 studies had grade III evidence (out of IV) that vaccination before COVID reduces subsequent Long COVID—Impact of COVID-19 vaccination on the risk of developing Long COVID and on existing long COVID symptoms: A systematic review

Four additional references showing that vaccination decreases risk of Long COVID include:

Financial Declaration: No one at the CIBS Center has any financial conflicts of interest with any companies that created or sell COVID vaccines. We do not make any money from this website and have no paid consultancies with any pharmaceutical companies or vaccine products or advertising. We are strictly a non-profit research center. We remain dedicated to providing public health information that is derived from the peer-reviewed scientific literature.

What can I do?

The most effective method of preventing yourself from Long COVID is avoiding becoming infected or reinfected with COVID-19.

Use multiple methods to increase your protection:

  • Wear a mask, test before gathering
  • Filter and ventilate indoor air
  • Practicing proper hand hygiene
  • Avoiding close contact with those who have or are at risk of having COVID-19
  • Stay up to date on vaccinations. This helps to prevent infection since breakthrough cases less frequently report Long COVID symptoms compared to those who are unvaccinated.

The Best Type Of Doctor To See If You Have Long COVID

With Long COVID, it is important to listen to your body and the ways that you expend energy during the day, including cognitive, physical, and emotional energy.  An important concept often discussed among those with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is the strategy of Pacing.  Pacing is about balancing rest and activity in order to avoid post-exertional malaise (PEM).

Kid holding their head in their hands looking out the window

Getting Care/Advocacy

First of all, never lose hope during your recovery. Second, remember that you are the expert of your own illness. Third, while the number of symptoms and severity of illness can often be overwhelming, it’s important to know that you are not alone. There are numerous support groups available worldwide. Some people prefer one close to their home, while others join an online version of a support group.

Again, please remember, you are not alone. If you are scared you or a loved one are at risk for self-harm and need to speak to someone, please consider calling the Suicide hotline (call or text 988) or contact one of the following:

In addition, local state groups can be found on Facebook.

Scientists and clinicians are working hard to learn about this condition and possible treatments. Efforts are also being made to increase awareness and access to care surrounding Long COVID. The Comprehensive Access to Resources and Education (CARE) Act, for example, is a bill backed by senators to increase research on and education about Long COVID to improve care. 


If you have new onset difficulty breathing, severe pain, visual or hearing problems, difficulty moving your arms or legs, or bleeding problems please seek care at the closest emergency department.

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