Despite the plethora of symptoms reported by patients with long COVID, a new study points to just seven that are unique to the illness. However, some long COVID researchers and doctors who've treated the disease believe this list is far from comprehensive.
The goal of the study was to look for long COVID symptoms that appear or persist more than a month after the initial infection and are distinct from symptoms of other common respiratory viruses, such as the flu or common cold. To do so, researchers used Cerner Real-World Data, a database containing information extracted from the electronic medical records from 122 health systems in the U.S.
They analyzed data from electronic health records of more than 17,000 patients diagnosed with COVID before April 14, 2022; more than 17,000 patients diagnosed with a different respiratory virus between March 1, 2020, and April 1, 2021; and 15,694 people with no virus diagnosis but who sought health care between 2020 and 2022.
Researchers concluded that some symptoms typically associated with long COVID do not appear more often after a COVID infection than they do with other respiratory viruses, according to the report published in Open Forum Infectious Diseases.
Compared to other viral respiratory illnesses, long COVID was most strongly associated with:
- Heart palpitations (fast beating, fluttering or pounding)
- Hair loss
- Chest pain
- Dyspnea (difficulty breathing)
- Joint pain
- Obesity in the postinfectious period
The hope is that this research will help patients and their doctors more easily recognize long COVID, study co-author Dr. Adnan Qureshi, neurologist at University of Missouri Health Care, tells TODAY.com. The research may help “health care providers know what they should be screening for,” Qureshi adds.
The surge in long COVID cases caught the health care system by surprise, Qureshi says.
“We thought once you survived the acute infection, then everything would be over,” he explains. “Now that survival has improved a lot, it’s quite apparent that this is not a one-time thing for many.”
“There has been a dramatic shift in disability and loss of productivity on a nationwide scale that is quite out of line with what we expected,” Qureshi adds. “The whole health care system has to gear up to meet that existing demand.”
Qureshi admits that the list of seven symptoms might not be the last word on the topic. “This is a work in progress,” he says. “It’s possible that some of the symptoms did not come out as significant in this analysis.”
Dr. Lawrence Purpura, director of Columbia University Irving Medical Center’s long COVID clinic, tells TODAY.com that the main strength of the new study is the number of patients it includes. But he adds that the study missed some of the cardinal symptoms of long COVID, aka post-COVID syndrome — most likely due to the underlying data. Chief among theses symptoms are:
- Brain fog
- Disabling fatigue
- Dysfunction of the autonomic nervous system, which controls subconscious bodily functions, such as breathing, heart rate and blood pressure
The dysfunction of the autonomic nervous system explains why some patients’ heart rates skyrocket after climbing two or three steps, and that symptom may be what the authors of the new study are listing as heart palpitations, Purpura says.
But there are numerous issues with using electronic medical records to make conclusions about long COVID, Purpura explains.
First, the study depends on doctors knowing enough about long COVID to correctly enter the diagnostic billing code for the illness into the patient’s record, he says. Moreover, many patients with mild cases of COVID aren't tested for COVID, so it’s wrong to assume that the 15,694 patients in the control group never had COVID.
As a result of the state of testing during the time period covered by the study, people with severe illness were most likely to be tested for COVID by a health care provider.
“In my clinic, I am seeing a lot of patients who were fully vaccinated and who have gone on to develop a prolonged case of long COVID, despite having had a mild case of COVID,” Purpura says. “My concern is that by missing some of the key characteristics of long COVID, we’d be doing patients a disservice.”
David Putrino, Ph.D., director of rehabilitation innovation for the Mount Sinai Health System, tells TODAY.com that, right now, electronic medical record-based studies of long COVID shouldn't be seen "as anything other than general hypothesis-generating pieces of work.”
“We need to stop treating these studies as the be all and end all of science just because of the large (number of patients) and despite serious methodological flaws," he adds.
Like Purpura, Putrino has found that the majority of people with persistent long COVID symptoms had a mild case of COVID, so they were unlikely to have positive test results in their medical records.
He adds that one of the big symptoms missed by the new study is “exertional malaise,” the crushing fatigue some patients experience after minor physical exertion. “This is a cardinal symptom of long COVID, and it’s been left out.”
Unfortunately, many health care providers don’t know how to treat this symptom, Putrino says. They think that patients are out of shape from being sick and just need to work up to a higher level of fitness, he adds.
“The reason they are not able to walk a block isn’t because they spent two weeks on the couch recovering from COVID,” Putrino explains. “They are experiencing this because they have inflamed blood vessels, persistent virus still rampaging through the body,” and malfunctioning mitochondria, the power plants of the cells that provide energy to essentially keep the lights on.
“If you try to exert yourself, it’s like someone poisoned you,” Putrino says. “You crash for weeks on end.”