Diagnosing long-term COVID is a risky exercise as this disease is still poorly defined.
A Canadian research team led by Professor Patrick Archambault from Laval University demonstrates this in the journal Nature Communications reporting that a percentage high number of people who have not had COVID-19 still present symptoms characteristic of long COVID.
The research team recruited 6,723 people who presented to the emergency room of one of the 33 participating hospital centers between October 18, 2020 and February 28, 2022. “These people consulted for health problems that were not were not necessarily linked to a respiratory infection”, specifies Patrick Archambault, professor at the Faculty of medicine, researcher at VITAM Sustainable health research center and emergency intensivist at the Chaudière-Appalaches Integrated Health and Social Services Center. Scientists have divided these people into two groups. The first consisted of 3933 subjects who had tested positive for COVID-19 during the 14 days preceding their emergency visit, at the time of their emergency visit or in the 14 days following. The other 2,790 subjects, who formed the control group, were also tested for COVID-19 during this period, but the result was negative. “In addition, they did not have a positive test for COVID-19 during the entire duration of their participation in the study, i.e. between 6 and 12 months,” adds Professor Archambault.
All of these people were subsequently contacted to find out if they had had any symptoms during the first three months following their emergency room visit. According to the definition of the World Health Organization (WHO), these symptoms are the distortion of tasteloss of smell, persistent cough, dizziness, pain, difficulty breathing sleepdifficulty concentrating, problems with memoryshortness of breath or disproportionate fatigue after exercise physique.
“These symptoms must have newly appeared after a confirmed or suspected COVID-19 infection, they must still be present three months after infection, they must have lasted for at least two months and not be attributable to another condition,” recalls Professor Archambault.
Analyzes showed that 39% of people in the COVID-19 group met the diagnostic criteria for long COVID. “Doctors who would have examined these people could have concluded, based on the WHO definition, that they had long COVID,” believes the researcher.
What follows is more surprising. Nearly 21% of people who had not tested positive for COVID-19 and who did not believe they had this disease also presented at least one of the symptoms of long COVID. “There is a slim possibility that some of these people had asymptomatic COVID-19 in the months following their visit to the emergency room,” recognizes Professor Archambault. On the other hand, I believe that this result above all demonstrates the lack of specificity of long COVID symptoms The result is that there is possible overdiagnosis of this disease.
This vagueness can have clinical repercussions, he continues. “On the one hand, people whose symptoms are falsely attributed to long COVID may not receive the treatment that would be appropriate for their condition. On the other hand, overdiagnosis of long COVID may harm efforts to better understand and to better treat this disease Until we have valid biomarkers for long COVID, we must continue to test, during the acute phase of the disease, all people in whom we suspect COVID-19. would thus avoid including in the group people suffering from long COVID people who have not had COVID-19.”
The other signatories of the study published in Nature Communications which are attached to theLaval University are Martyne Audet, Matthew Menear, Éric Mercier, Jean-Sébastien Paquette, Elyse Berger Pelletier and Sébastien Robert.
