raised the risks of long Covid back in July 2020, and in July 2022 highlighted the difficult battle many people — often called “long-haulers” — continue to experience months and even years after a SARS-CoV-2 infection. Many long-haulers continue to speak out, raising awareness and advocating for better understanding and treatment of this chronic illness, including actress Alyssa Milano, the NHL’s Brandon Sutter, Clemson defensive end Justin Foster, and Senator Tim Kaine of Virginia. Now, almost three years into the pandemic, we have more information about what causes long Covid, its clusters of symptoms, how to prevent it, who is most at risk — but still far too little to offer those who are struggling.
What is long Covid?
A person is considered to have long Covid — sometimes called Post-Acute Sequelae of SARS-CoV-2 Infection (PASC) or Post Covid-19 Condition (PCC) — if 12 weeks after being infected they continue to have symptoms or develop new symptoms that can’t be explained by an alternative diagnosis. Long Covid is a term that covers multiple symptoms, conditions, and complications thought to occur after or because of a Covid infection.
The SARS-CoV-2 virus can damage blood vessels throughout the body. This is often seen in the form of blood clots, inflammation, and stiffened arteries. Covid also appears to damage nerves, linger in organ tissues, and impair the immune system, making people vulnerable to other viruses and bacteria either already in their bodies or that they encounter later on. This is why people experiencing long Covid report symptoms in so many areas of the body, including the brain, lungs, heart, reproductive organs, kidneys, and legs.
What are the impacts of long Covid?
Physical exhaustion, “brain fog,” and shortness of breath are the three most common symptoms of long Covid, but far from the only ones. A study involving 3,672 patients from the United States, Canada, the UK, and the EU found 203 symptoms unique to long Covid, often appearing in clusters. Symptoms tend to cluster based on sequence of onset and by age group — for example, stomach issues for those under 21 and neurological disturbances for those aged 21–45 — but every age group is affected and none is immune.
One particularly concerning symptom is called Post-Exertional Malaise (PEM). According to that same study, 89% of long Covid patients experienced disabling physical exhaustion or brain fog after minor physical or mental exertion. 68% of those who experienced PEM said that their symptoms lasted for days, hindering their ability to go to work or otherwise return to life as normal.
In addition to this array of symptoms, evidence points to long-term and life-threatening complications caused by long Covid related to the heart, brain and other organs, and the immune system. One disabling manifestation with increasingly clear documentation of relation to SARS-CoV-2 infection is Postural Orthostatic Tachycardia Syndrome (POTS), with patients becoming lightheaded with low blood pressure and rapid pulse when they stand up.
Who’s at risk?
Anyone can get long Covid — including people who are young, healthy, or who initially had a mild or even asymptomatic infection. Resolve to Save Lives, the organization I lead, launched a campaign called “Voices of Long Covid” that features the heart-wrenching stories of three young long-haulers.
Although no one is free from the risk of long Covid, research has revealed that some people are more likely to develop severe symptoms and complications — including people who are medically vulnerable, unvaccinated or who experienced a severe infection that required hospitalization. Those who are older tend to have more pre-infection comorbidities that place them at higher risk in general, as do people who have high BMI, sedentary lifestyle, or history of smoking and drinking.
Many of the socio-economic factors that increase risk for getting infected with Covid — such as low socioeconomic status and lack of access to healthcare — also appear to increase risk of developing long Covid. Being a health care worker or essential worker may increase risk for developing long Covid due to the increased risk of exposure to Covid positive individuals.
Risk might differ between men and women. One study found women to be 1.22x more likely to develop long Covid and experience a wider range of symptoms, including ears-nose-throat, respiratory, musculoskeletal, gastrointestinal, and neurological. Men, though at lower risk than women overall, were found to be at higher risk of developing end-stage kidney disease, heart damage, and diabetes.
Different hypotheses for this include hormonal differences between men and women, naturally increased immune responses among women of reproductive age that dysregulate after a Covid infection, and because long Covid is an autoimmune disorder, a type of illness which tends to be more common in women. It could also be that more women seek care for long Covid symptoms than men.
A large study from the U.S. Department of Veteran Affairs found that the risk for developing long Covid and other complications increases each time someone gets Covid. Though the cohort of veterans is not demographically representative of the overall U.S. population, it does coincide with increasing evidence that organ damage from SARS-CoV-2 infection can be cumulative, meaning that re-infection may also be a risk factor. Until we know more, it’s best to avoid getting reinfected with Covid to the extent possible, even for people who have successfully recovered from a past infection and have no lingering symptoms.
How common is long Covid?
There remains a wide range of estimates of how likely a Covid infection is to cause long-term symptoms. Some analyses suggest that the rate is as low as 1% for those with an uncomplicated Covid infection, and as high as one third or more of those who were hospitalized for Covid. Because Covid infection is so common — approximately two-thirds of people in the United States have been infected at least once — even a low rate of long Covid following infection translates into a large number of people suffering.
CDC estimates that 1 in 7 adults in the U.S. have experienced long Covid symptoms at some point since the pandemic began (signifying incidence), and 1 in 14 adults are currently experiencing long Covid (signifying prevalence) — a quarter of whom experience significant activity limitations. This survey suggests that long Covid is twice as common in females as in males, and is most prevalent among Hispanics and White, Non-Hispanic people.