Only seven symptoms can be specifically linked to long COVID, according to the results of new study in over 50,000 patients. The researchers were surprised by the finding, given the massive number of potential long COVID symptoms that have previously been recorded in the literature.
“Despite an overwhelming number of long COVID symptoms previously reported by other studies, we only found a few symptoms specifically related to an infection from SARS-CoV-2, the virus that causes COVID-19,” said corresponding author Chi-Ren Shyu in a statement.
"Before we examined the data, I thought we would find an ample amount of the symptoms to be specifically associated with long COVID, but that wasn't the case."
Not long after SARS-CoV-2 turned the world upside down in early 2020, patients began taking to social media to share stories about the mysterious post-infection syndrome that would come to be called long COVID. These patients, often referred to as "long-haulers", had usually recovered from a mild COVID infection, but were experiencing lingering, debilitating symptoms that clinicians were helpless to try and explain. Over time, patient self-advocacy filtered through to medics and policymakers, and long COVID began to be taken more seriously.
In the intervening years, a prior COVID infection has been linked to damage in nearly every system in the body – from the respiratory system, to the brain, to the immune system and beyond. A recent review put the incidence of long COVID at 10 percent of infected people – that’s an estimated 65 million cases worldwide.
Now, this new study from the University of Missouri has examined the 47 most commonly reported symptoms, and found that only seven of them could be conclusively linked with the disease.
The team looked at real data from 52,461 people across the US, dividing them into three groups: people diagnosed with COVID and not other respiratory infections; people diagnosed with respiratory infections other than COVID (e.g. influenza); and people with neither COVID nor another respiratory infection.
The seven symptoms of long Covid
The analysis found that for up to a year post-COVID, specifically, people were more likely to develop heart palpitations, hair loss, fatigue, chest pain, shortness of breath, joint pain, and obesity.
“Our research was able to identify long-term sequelae [consequences] that are distinctive to COVID-19 and separate the post-COVID syndrome from other post-viral syndromes,” said study author Adnan Qureshi.
“The survivors still have symptoms that are at times disabling and preventing them from going back to work or the activities of their daily life.”
It is hoped that by increasing their knowledge of how long COVID presents in patients, doctors will be better equipped to recognize the symptoms quickly and help people to access appropriate treatment. The more we continue to learn about the virus and its effects, the greater our chances of predicting what it may do next.
“Now, researchers will be able to better understand how SARS-CoV-2 may mutate or evolve by creating new connections that we may not have known about before,” added Shyu. “Going forward we can use electronic medical records to quickly detect subgroups of patients who may have these long-term health conditions.”
The study is published in Open Forum Infectious Diseases.