Among the persistent symptoms most frequently described in the scientific literature are dyspnea (shortness of breath), asthenia (fatigue), joint and muscle pain, cognitive problems, digestive disorders, or even anemia. dysgeusia (loss of smell and taste). But most of these symptoms may also have been caused by other infections that occurred at the same time; they may also be related to a change in patient behavior and / or the fact that access to the health care system was greatly altered during the pandemic, which could have adversely affected treatment and / or delayed diagnosis. of other pathologies. Therefore, the researchers tried to shed light on the persistent symptoms that are in fact associated with a SARS-CoV-2 infection. Your results have just been published in The Lancet Regional Health – Europee.
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A study based on the general population
This prospective survey is part of the CONSTANCES study, a “generalist” epidemiological cohort launched in 2012, consisting of a representative sample of 200,000 volunteers between the ages of 18 and 69 at inclusion, including policyholders. general Social Security scheme. of 17 French departments. These participants are asked to complete a health questionnaire each year and undergo a health examination every five years.
The new study therefore differs from other research on the topic in that it is based on a cohort called the “general population”: most other studies are conducted from cohorts of symptomatic Covid patients, who are therefore not representative of all infected people, specify INSERM researchers.
Some 35,800 people in the CONSTANCES cohort were asked to complete two questionnaires during the first pandemic wave (between February and May 2020) about the acute symptoms experienced during the period (whether or not due to COVID-19). Serological tests were then performed (between May and November 2020) to look for a history of SARS-CoV-2 infection. Then, between December 2020 and January 2021, participants completed a third follow-up questionnaire focusing on symptoms that had persisted or persisted for at least two months.
Thus, the researchers were able to compare the persistence of symptoms between seven and eight months after the first wave in four groups of participants (called ECDC +, ECDC-, Séro + and Séro-): these were formed according to the history of symptoms, d according to the Covid criteria defined by theEuropean Center for Disease Control– and the result of your serological test.
Participants were considered “Sero +” if the serological test was positive for SARS-CoV-2 infection. They were considered “ECDC +” if they had experienced – and reported in at least one of the first two questionnaires – at least one of the following symptoms for at least 3 days: dysgeusia / anosmia, dyspnea, fever and cough. Other acute symptoms include headache, unusual asthenia, myalgia, joint pain, runny nose, nausea / vomiting, diarrhea, and skin problems.
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Increased risk of persistent anemia / dysgeusia, shortness of breath and fatigue
After excluding participants whose serology was not determined or who reported a diagnosis of COVID-19 after serology, 25,910 individuals were classified into the different groups. The study reveals that at least one persistent symptom was reported in 43% of ECDC + / Sero + group participants, 37.7% of ECDC + / Sero- group participants, and 20% of ECDC- / Sero + group participants. 23% of participants. participants in the ECDC- / Séro- group.
“The risk of dysgeusia / anosmia, dyspnea, and persistent asthenia was higher in the ECDC + / Sero + group than in the ECDC + / Sero- group.On the other hand, the risk of presenting the other symptoms that have been suggested related to long Covid (abdominal pain, sensory symptoms, sleep disturbances, etc.) was similar or higher in the ECDC + / Serum- group in the ECDC + / Serum + group. “This suggests that these persistent symptoms are common and often not specific to the causative agent.“, emphasize the authors of the study.
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Interesting fact: more than 80% of the symptoms reported in the first wave disappeared before the follow-up questionnaire, regardless of the serological result, with the exception of dysgeusia / anosmia and asthenia in the HIV-positive group (where these symptoms affect respectively ). 24% and 20% of individuals). The team also notes that there was no difference in persistent symptoms between the ECDC- / Sero + and ECDC- / Sero- groups, with the exception of palpitations that appeared to be more common in HIV-positive participants.
The researchers also noted a significant difference in the number of symptoms presented during the acute phase of the epidemic: in the group that did not show persistent symptoms, 70.1% of participants reported the absence of acute symptoms, compared to 50, 2% of the group. with at least one persistent symptom. That is, COVID-19 may cause persistent symptoms if it induces certain symptoms at the time of the acute episode of infection. “Promoting therapeutic and preventive strategies that reduce symptoms in the acute phase of the disease could have an effect on post-COVID symptoms.“The researchers concluded.
More research is being done to understand the mechanisms behind these “post-Covid” states.