What is Long Haul Covid and What Can We Do About It?

The stories just kept coming in. Told that barring the need for hospitalization, most patients with Covid-19 would recover in a few weeks, patients who didn’t feel like themselves for many weeks or even months after infection did not know where to turn. Was it all in their heads? Would they ever get better? Was this experience unique to Covid or were these typical post-viral symptoms? Why wasn’t the medical community paying attention?

As people everywhere struggle to understand and cope with the unprecedented implications of the Covid-19 pandemic, non-professionals played an essential role in bringing the reality of unexpected, prolonged symptoms following Covid-19 infection to the attention of the medical community. As such, what’s referred to as “long Covid” or “long haul Covid” is likely to be the first condition that emerged from patients using social media to compare symptoms and offer support (Callard & Perego 2021).

The hashtag #LongCovid was used first by Elisa Perego in May 2020, and the idea quickly spread on social media. The term was picked up by print and broadcast journalists and ultimately the scientific literature.

Because symptoms of long Covid include psychological phenomena such as increased depression and anxiety, mental health professionals will benefit from a better understanding of how long Covid can affect patients.

What Exactly Is Long Covid?

According to a research letter to JAMA by Sebastian Havervall and his colleagues, about 80 percent of patients who required hospitalization for the treatment of Covid-19 experienced symptoms that lingered for months after they first became sick. Even among people with milder cases, about 26 percent reported at least one troublesome symptom two months later and about 15 percent reported a troublesome symptom that lasted at least eight months.

A precise definition of long Covid is still needed. Symptoms are wide-ranging and fluctuate over time. Most commonly, patients report fatigue, dyspnea (difficulty breathing), loss of smell, loss of taste, cardiac abnormalities (chest pain and palpitations), cognitive impairment (fog), sleep disturbance, muscle pain, difficulty concentrating, headache, and symptoms of posttraumatic stress disorder (PTSD), depression, and anxiety. These symptoms are troubling enough to affect work, social, and home life. 

Acute or active Covid symptoms usually resolve in about four weeks. Symptoms continuing past four weeks are now considered to be long (or post-acute) Covid (Nalbandian et al. 2021). Post-acute Covid has been divided into subacute/ongoing Covid between four and 12 weeks and chronic/post-Covid after 12 weeks.

Examples of Post-viral Syndromes

The idea of a post-viral syndrome is nothing new in medicine. Viruses can stay in the body’s tissues long after major symptoms recede. The damage they cause to the body can also produce long-lasting symptoms. Understanding the variations in post-viral syndromes can help us focus discussions of long Covid more accurately. 

In some cases, viruses stay dormant within the body, surfacing periodically to cause similar symptoms such as recurrent cold sores from herpes infections. They can also reawaken decades later to cause new types of problems, such as the development of shingles following a childhood bout of chickenpox. Both chickenpox and shingles are the result of infection with the varicella-zoster virus. 

Notable post-viral syndromes occur following infection with Ebola, polio, and Epstein-Barr viruses. People who have recovered from Ebola can experience muscle, eye, and neurological problems. The virus can be found in the eyes and testes months following recovery, possibly due to reduced immune responses in these tissues. The ability of the virus to remain in semen raises the unpleasant possibility that Ebola, once established, could be sexually transmitted. Research is underway to gain a further understanding of the long-term impact of Ebola. 

Polio is relatively rare today due to effective vaccines, but if a person does contract polio at a young age, post-polio symptoms can emerge as much as decades later. Due to the specific action of the poliovirus, which destroys motor neurons, the symptoms of post-polio syndrome tend to be related to movement as well. Patients experience muscle fatigue and atrophy as well as difficulty breathing and swallowing. 

The Epstein-Barr virus (EBV), a member of the herpes family of viruses, initially produces mononucleosis, characterized by sore throat, fatigue, and swollen lymph glands. Most people have been exposed to EBV, usually in childhood, when the virus may cause either no symptoms or symptoms that are indistinguishable from a mild flu or cold. Adolescents and adults contracting EBV for the first time often experience more noticeable symptoms, but usually recover within one month. Once infected, the virus remains in the body indefinitely. On rare occasions, individuals are unable to hold the virus in check, leading to long-term symptoms. In others, the virus can reactivate and cause additional problems with immune function.

Coronaviruses, including Covid-19, are known to produce post-viral syndromes. The viruses themselves do not appear to stay in the body for more than a few weeks, but rather produce damage that can be long-lasting. Both the 2003 SARS-1 epidemic and the 2012 Middle East respiratory syndrome (MERS) outbreak produced persistent symptoms in some patients. Because of the genetic similarity between these viruses (Covid-19 has a 79 percent overlap with SARS-1 and 50 percent with MERS), it is logical to expect similar outcomes of Covid infection. 

In addition to producing similar acute physical symptoms, SARS-1 and MERS share with Covid-19 the ability to create new cases of anxiety, depression, PTSD, and sleep disturbance in up to 40 percent of survivors.

Some argue that long Covid is simply another version of myalgic encephalitis or chronic fatigue syndrome (ME/CFS). Long dismissed by the medical community as a purely psychological disorder, ME/CFS can result from a post-viral condition. While both syndromes typically feature fatigue, long Covid is distinct from ME/CFS in the frequency with which patients experience breathing difficulties. An important lesson from ME/CFS, however, is that patient reports should be taken seriously and not assumed to be psychological in origin without further information.

Where Do Post-viral Symptoms Come From?

You may have read that the Covid-19 virus enters the body by interacting with angiotensin-converting enzyme-2 (ACE2) receptors. These receptors are found in many different cells of the body and are particularly common in the cells lining the lungs. Their major function is to “put the brakes” on the activity of a protein called angiotensin II (ANGII). 

ANGII has its legitimate purposes, such as raising blood pressure and initiating inflammation, but too much of it can cause tissue damage. When the virus interacts with the ACE2 receptors, the receptors are inactivated, removing the body’s protection from too much ANGII activity. The amount of ANGII activity is directly related to the severity of Covid-19 symptoms.

The effects of Covid-19 in acute, active cases are relatively well understood. Covid-19 can damage the body through several mechanisms: 

  • Direct invasion of tissues by viruses
  • Damage to blood vessels
  • Disruption of the immune system, often leading to an exaggerated response
  • Increases in blood clotting
  • Distortions of the angiotensin-converting enzyme-2 (ACE2) pathway

What are the Possible Mental Health and Cognitive Impacts of Covid-19?

While the impacts of the Covid-19 virus on breathing, cardiac function, and circulation are rather straightforward, the sources of psychological symptoms are more diverse and variable. Patients who have recovered from acute Covid-19 infection are more likely than patients recovering from the flu and other similar respiratory tract infections to develop new, previously undiagnosed psychological disorders. These new disorders might arise from multiple processes initiated by Covid-19 infection.

Researchers continue to debate the ability of Covid-19 to infect neurons directly. Instead, psychological effects might be due to damage to the blood vessels supplying the brain and to the blood-brain barrier, which typically protects the brain from circulating toxins. As a result, brain tissues in Covid-19 patients are likely to experience inflammation. The degree of inflammation of brain tissues is positively correlated with the severity of cognitive and behavioral changes in patients (Nalbandian et al. 2021). 

Other possible sources of neural damage include disruption of the lymphatic system of the brain and viral invasion by way of the olfactory system. By weakening the immune system, Covid-19 might also reduce a patient’s ability to thwart the reactivation of other viruses, such as the herpes viruses, which can contribute to further inflammation in the brain. 

A weakened immune system, such as in cases of HIV/AIDS, also leaves the brain vulnerable to fungi, bacteria, and parasites that are otherwise easily controlled. Approximately 11 percent of the US population over the age of 6 years harbors the parasite Toxoplasma gondii (T. gondii), which has been linked to epilepsy, cancer, Alzheimer’s disease, and schizophrenia (CDC 2019). Patients with conditions requiring suppression of the immune system are particularly vulnerable to chronic symptoms caused by reactivated T. gondii. 

The brain fog that frequently follows Covid-19 might be related to PTSD or deconditioning, which refers to the wide range of physical changes that can result from long periods of inactivity, such as hospitalization. 

However, brain fog has also been observed in people with relatively mild cases of Covid-19 that do not require extended bed rest. This raises the likelihood that other factors are involved. For example, brain fog might be the result of disruptions to the functioning of the autonomic nervous system, or dysautonomia.

Much additional research is necessary before we gain a full understanding of the sources of adverse psychological outcomes of Covid-19.

Individual Responses to Covid-19

It is challenging to predict which patients might develop long Covid, let alone why they do. The course of the disease itself is characterized by important demographic differences, such as age. Older adults appear far more vulnerable to severe impairment and death. 

Diagnosis and treatment might be affected by additional variables, including socioeconomic status and access to health care. The vast majority of people with Covid do not require hospitalization, so assessing their experience with Covid or its after-effects can be difficult. These and related factors complicate the task of researchers trying to obtain good answers.

A small study sponsored by the CDC (Yomogida et al. 2021) showed that women, people between the ages of 40 and 54, African Americans, and people with pre-existing conditions (diabetes, cardiovascular disease, etc.) were more likely than others to experience symptoms of long Covid.

A much larger British study followed 20,000 people who were diagnosed with Covid to see which individuals would go on to develop symptoms of long Covid (Office of National Statistics 2021). This study confirmed the prevalence of women and middle-aged individuals in the population experiencing long Covid. However, this study relied on self-report, rather than a medical diagnosis of continued symptoms. 

It seems logical to assume that the more severe your bout with Covid, the more likely you are to experience long Covid, but that does not seem to be the case in data collected so far. Even mild cases of Covid seem to have the ability to develop into long Covid.

The severity of acute Covid might be related to a person’s existing level of autoantibodies or antibodies that attack the body’s own tissues instead of foreign intruders like viruses. Many viruses, including EBV, have been implicated in autoimmune disorders such as multiple sclerosis. While researchers are investigating the possibility that the Covid virus provokes autoimmune responses, this research has not yet been extended to cases of long Covid.

We don’t know for sure how the concurrent mental health of patients influences their risk for long Covid. Pandemics worsen the mental health of the general population and those who have pre-existing psychological disorders (Neelam et al. 2021). 

Not only does the stress of a pandemic contribute to poor mental health, but people are less likely to seek out treatment. The social isolation resulting from lockdowns and quarantines can contribute to further problems. Researchers will likely be unpacking these variables related to both Covid itself and long Covid for years to come.

Recommended Mental Health Treatment Plans for Long Covid

Ideally, patients recovering from acute Covid-19 should be assessed regularly over the following months for signs of post-viral syndrome. This assessment should include standard measures of anxiety, depression, PTSD, sleep disturbance, fatigue, and headaches. Obviously, any indication of the presence of these conditions should lead to appropriate therapies. Because of the diversity of symptoms and necessary treatments, interdisciplinary teams become especially valuable in managing patients.

In addition to standard psychological and psychiatric care, patients should also be reassured that their experiences are valid and that they are not imagining their symptoms.  

Not only have peers been instrumental in the initial identification of long Covid, but they have also organized networks of peer support. Among the notable peer support groups are the following:

  • Covid Advocacy Exchange
  • National Patient Advocate Foundation Covid Care Resource Center
  • Long-haul Covid Facebook groups
  • Body Politic Covid-19 Support Group
  • Survivor Corps
  • Patient-Led Research for Covid-19

Not only do these groups help others with long Covid, but they are also important communication channels that health professionals can use to share factual information and solicit feedback.


  1. Callard, F. & Perego, E. (2021). How and why patients made Long Covid.
  2. Social Science & Medicine, 268, 113426. https://doi.org/10.1016/j.socscimed.2020.113426
  3. Centers for Disease Control and Prevention (CDC; 2019). Toxoplasmosis – Epidemiology & risk factors. https://www.cdc.gov/parasites/toxoplasmosis/epi.html
  4. Neelam, K., Duddu, V., Anyim, N., Neelam, J., & Lewis, S. (2021). Pandemics and pre-existing mental illness: A systematic review and meta-analysis. Brain, Behavior, & Immunity – Health10, 100177. https://doi.org/10.1016/j.bbih.2020.100177
  5. Yomogida, K., Zhu, S., Rubino, F., Figueroa, W., Balanji, N., & Holman, E. (2021). Post-acute sequelae of SARS-CoV-2 infection among adults aged ≥ 18 years—Long Beach, California, April 1—December 10, 2020. MMWR Morbidity and Mortality Weekly Report, 70, 1274—1277. http://dx.doi.org/10.15585/mmwr.mm7037a2
Laura Freberg, PhD

Laura Freberg, PhD

Writer & Contributing Expert

Laura Freberg serves as professor of psychology at Cal Poly, San Luis Obispo, where she teaches introductory psychology and behavioral neuroscience.

Dr. Freberg is the author or co-author of several textbooks, including Discovering Psychology: The Science of Mind, Discovering Behavioral Neuroscience, Applied Behavioral Neuroscience, and Research Methods in Psychological Science. She served as President of the Western Psychological Association (WPA) in 2018-2019.