What we know and don’t know about long COVID

Much about the chronic condition remains unclear nearly 3 years into the pandemic

Authhors:  Daniel de Visé | Oct. 20, 2022 Changing America

Story at a glance

  • The lack of diagnostic tools for long COVID-19 make the condition difficult to conclusively identify or study.

  • Studies place the prevalence of long COVID-19 anywhere between 4 percent and 48 percent of people who have been infected with the virus. 

  • Other aspects of the condition, such as how long symptoms may persist and how common it will be in the future, also remain unclear. 

After two years of research and one of the largest public health campaigns in human history, doctors and scientists don’t yet have a test to detect the mysterious affliction called long COVID-19, let alone a head count of the afflicted. 

Based on the latest wave of studies, long COVID-19 may beset 4 percent of the population who catch the virus, or 14.8 percent, or 48 percent. Its toll on the body spans dozens of possible symptoms, from fatigue to chest pains to fuzzy thinking to hair loss. The symptoms overlap with those seen in scores of other illnesses.  

Many long COVID-19 cases clear up after several months or a year. Some seem to be permanent. Only time will tell. 

“What do we mean when we say long COVID? We’re still figuring it out,” said Dr. Josh Fessel, a senior clinical adviser and COVID-19 specialist at the National Institutes of Health (NIH). Along the way, he said, “we’re learning a lot about what recovery looks like after a significant illness.” 

long COVID-19 study released last week by Scottish researchers raised eyebrows around the globe. Six to 18 months after COVID-19 infection, 48 percent of people surveyed said they had not fully recovered.  

That report is an outlier. The World Health Organization puts the prevalence of long COVID-19 at 10 to 20 percent. Other recent estimates range across the map. An ongoing survey by British health officials, updated in July, found long COVID-19 in only 4 percent of cases. A Canadian government survey, updated this week, found that 14.8 percent of adults with COVID-19 retained symptoms three months after infection. A U.S. government survey, updated this month, found that 30 percent of adults who had the coronavirus believed they had experienced long COVID-19. 

For many Americans, long COVID-19 now looms as a larger worry than acute COVID-19, the first round of disease triggered by the viral invader. Vaccinations and weakening variants have vastly lowered the odds that people without underlying conditions will wind up hospitalized or dead from the acute version of the ailment. 

“People don’t talk about just getting COVID any more,” said Tara Leytham Powell, professor of social work at the University of Illinois. “Long COVID is more of a fear.” 

Ashley Drapeau caught COVID-19 in December 2020. A month later, she said, “it just seemed like it wasn’t getting any better. I was still having shortness of breath. I was having migraines. … Lack of appetite, nausea. It seemed to go on and on.” 

Drapeau took most of 2021 off. Now she’s back at work, running a long COVID-19 program at the George Washington University Center for Integrative Medicine. She’s operating at “about 80 percent.” She has never fully recovered. 

In calculating the prevalence of long COVID-19, researchers struggle to gather basic data. There is no way to conclusively diagnose long COVID-19, so most research relies on self-reported information obtained through surveys. Respondents don’t always know if they had COVID-19. They can only guess.  

“There’s no test. There’s no way to evaluate it,” said Dr. Priya Duggal, an epidemiologist and professor at the Johns Hopkins Bloomberg School of Public Health. “You can only ask people to report it themselves.” 

Duggal works on an ongoing long COVID-19 survey at Johns Hopkins, a project that began with the first reports of lingering illness in the spring of 2020.  

“We expected there would be a long-term consequence,” she said. “We weren’t expecting what we’re seeing now.” 

Hopkins researchers have found that one-third of patients report symptoms of long COVID-19. A much smaller group, around 3 percent, was identified as suffering from severe long COVID-19, “meaning that they can’t function in their day-to-day life,” Duggal said. “They can no longer walk a quarter of a mile, or up a flight of stairs. Can’t do things like vacuum. It affects their ability to do their jobs, take kids to school.”  

Though researchers have not reached consensus on some of the specifics, they generally agree that long COVID-19 is a constellation of symptoms that can endure for months or years after infection, sometimes emerging after an illusory recovery. The most common symptoms seem to be fatigue, shortness of breath and that blurry mental state known as COVID fog. 

Researchers often file long COVID-19 sufferers into two groups. The smaller contingent, perhaps 1 to 5 percent of all coronavirus cases, suffer symptoms so severe that they “can’t live normal lives,” Duggal said. The larger camp of COVID-19 “long-haulers,” somewhere between 5 and 50 percent of all cases, manifest relatively mild symptoms that don’t hinder daily routines of work, school, shopping and sleep.  

Some in that camp may not have long COVID-19 at all.  

In the Scottish study, 91 percent of people who believed they had long COVID-19 reported one or more symptoms associated with the affliction. But at least one of the same symptoms appeared in more than half of the group that had never caught COVID-19.  

Some people confuse essentially random symptoms with resurgent COVID-19, experts say. Others could be coping with the vagaries of recovery from a serious illness. Still others may be fighting symptoms that linger mostly in the mind. 

“A lot of these are symptoms of depression and anxiety,” said Dr. Steven Dubovsky, chairman of psychiatry at the University of Buffalo. “I’m sure there’s a population of people who got sick and stayed sick for complicated psychological reasons. That doesn’t mean they aren’t sick.” 

One problem with diagnosing long COVID-19 lies in the bewildering array of symptoms. One recent Dutch study counted 23. More common: loss of taste and smell, muscle pain, back pain, headache and lethargy. Less common: “heavy arms and legs,” stomach pain, diarrhea and tingling extremities.  

“We talk about long COVID like it’s a thing,” said Fessel of NIH. “And I think the truth is that what we’re learning, and what we’ve had a sense of for a while, is that there are different flavors of long COVID. It seems like there are some people who really have a lot of the fatigue, the cognitive changes. … There are people who don’t have much of that, but they’re really short of breath with activity levels that never used to bother them, and that persists for months. There are people with real high heart rates. All of these fall under the umbrella of long COVID.” 

One uncertainty lies in the very definition of “long.” Some researchers define long COVID-19 as symptoms enduring past three or four weeks. Others draw the line at three months.  

Another imponderable: Fickle public interest in COVID-19 surveys. People who haven’t recovered from the virus may be more likely to answer a long COVID-19 survey than people who have. Educated white women, in particular, seem to answer these surveys at markedly higher rates than people in other demographic groups.  

Not all the news about long COVID-19 is bad. One good tiding: Keeping up with vaccines seems to reduce the chances of contracting long COVID-19.  

U.K. health officials have found encouraging signs that weaker variants, as well, correlate to lower rates of long COVID-19.  

“Our research and other research have found that if you’re fully vaccinated, your risk of having long COVID 12 weeks after an omicron infection is about half what it was with delta,” said Daniel Ayoubkhani, principal statistician at the U.K. Office for National Statistics.  

Other researchers disagree. And even if the rate of long COVID-19 decreases over time, owing to vaccination or milder variants, the sheer number of infections should guarantee a steady stream of long COVID cases for a long time to come. The impact of those cases, on individuals and on society, could be massive. One recent study suggests long COVID-19 may have already sidelined 4 million American workers.  

“That’s over $100 billion a year, in terms of lost wages,” said Drapeau, of George Washington University. “That’s a pretty big deal.”

Covid-19 Vaccine Analysis: The most common adverse events reported so far


As of July 19, 2021 there were 419,513 adverse event reports associated with Covid-19 vaccination in the U.S., with a total of 1,814,326 symptoms reported. That’s according to the federal Vaccine Adverse Event Reporting System (VAERS) database.

Report an adverse event after vaccination online here.

Each symptom reported does not necessarily equal one patient. Adverse event reports often include multiple symptoms for a single patient.

Reporting of illnesses and symptoms that occur after Covid-19 vaccination does not necessarily mean they were caused by the vaccine. The system is designed to collect adverse events that occur after vaccination to uncover any patterns of illnesses that were not captured during vaccine studies.

Read CDC info on Covid-19 vaccine here.

Scientists have estimated that adverse events occur at a rate many fold higher than what is reported in VAERS, since it is assumed that most adverse events are not reported through the tracking system. Reports can be made by doctors, patients or family members and/or acquaintances, or vaccine industry representatives. 

Read: Exclusive summary: Covid-19 vaccine concerns.

Some observers claim Covid-19 vaccine adverse events are not as likely to be underreported as those associated with other medicine, due to close monitoring and widespread publicity surrounding Covid-19 vaccination.

Approximately 340 million doses of Covid-19 vaccine have been given in the U.S. Slightly less than half of the U.S. population is fully vaccinated.

According to the Centers for Disease Control (CDC) and Food and Drug Administration (FDA), the benefits of Covid-19 vaccine outweigh the risks for all groups and age categories authorized to receive it.

Watch: CDC disinformation re: studies on Covid-19 vaccine effectiveness in people who have had Covid-19.

The following is a summary of some of the most frequent adverse events reported to VAERS after Covid-19 vaccination. (It is not the entire list.)

Most common Covid-19 vaccine adverse events reported as of July 19, 2021

Yellow highlighted adverse events are subjects of investigations, warnings or stated concerns by public health officials. For details, click here.

128,370 Muscle, bone, joint pain and swelling including:

  • 39,902 Pain in extremity
  • 37,819 Myalgia, muscle pain, weakness, fatigue, spasms, disorders, related
  • 30,138 Arthralgia, joint pain or arthritis, swelling, joint disease, bone pain, spinal osteoarthritis
  • 14,682 Back pain, neck pain
  • 5,829 Muscle and skeletal pain, stiffness, weakness

119,866 Injection site pain, bleeding, hardening, bruising, etc.

105,332 Skin reddening, at injection site or elsewhere, rash, hives

100,564 Fatigue, lethargy, malaise, asthenia, abnormal weakness, loss of energy

89,302 Headache, incl. migraine, sinus

68,252 Vomiting, nausea

68,064 Fever

63,133 Chills

60,913 Pain

49,574 Dizziness

34,076 Flushing, hot flush, feeling hot, abnormally warm skin

31,785 Lung pain or abnormalities, fluid in lung, respiratory tract or lung congestion or infection, wheezing, acute respiratory failure including:

  • 23,005 Dyspnoea, difficulty breathing
  • 1,398 Pneumonia
  • 1,128 Respiratory arrest, failure, stopped or inefficient breathing, abnormal breathing
  • 563 Covid-19 pneumonia
  • 265 Mechanical ventilation
  • 217 Bronchitis

30,909 Skin swelling, pain, tightness, face swelling, swelling under skin, hives, angioedema including:

  • 7,579 Skin pain, sensitivity, burning, discoloration, tenderness

25,319 Heart failure, heart rhythm and rate abnormalities, atrial fibrillation, palpitations, flutter, murmur, pacemaker added, fluid in heart, abnormal echocardiogram including:

  • 3,105 Heart attack or cardiac arrest, sudden loss of blood flow from failure to pump to heart effectively, cardiac failure, disorder

22,085 Itchiness

29,861 Sensory disturbance including:

  • 8,236 Tinnitus, hearing noise
  • 7,951 Abnormal vision, blindness
  • 6,349 Ageusia, loss of taste, altered taste, disorders
  • 2,249 Anosmia, loss of smell, parosmia (rotten smell)
  • 2,075 Hypersensitivity
  • 1,560 Sensitivity or reaction to light 
  • 890 Hearing loss, deafness