November 30, 2021

Vaccination also decreases the risk of long Covid

At the question : “Does the vaccine prevent the long Covid?” », Odile Launay, university professor at the University of Paris in infectious diseases, answers without hesitation: “Yes, by two mechanisms: on the one hand, by reducing the risk of being infected with Covid, on the other hand, by reducing by two the risk of long-term Covid in the event of infection in vaccinated persons. “

An article published on 1is September in the Lancet Infectious Diseases is, according to her, “Very convincing”. This work by Claire Steves’ team at King’s College London focused on data from users of the Covid Symptom Study tracking app in the UK, which she compared with uninfected or unvaccinated people. Among the 592 people fully vaccinated (so with two doses), only 5.2% still suffered from symptoms after 28 days, against 11.4% for unvaccinated subjects.

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Beyond the preventive side, could the vaccine alleviate certain symptoms for people suffering from long Covid? “For now, we don’t know”, answers Odile Launay. The results available are mixed.

Coordinated by epidemiologist Viet-Thi Tran, a study made available for pre-publication on 1is October, and conducted among 910 patients with a long Covid recruited in the ComPaRe cohort, showed that “The vaccination significantly reduced the symptoms of long Covid” (16% of patients reported complete disappearance of symptoms at 120 days compared to 7.5% in the control group) and the impact of this on daily life (38.9% of patients reported a significant impact of the disease in their lifetime compared to 46.4% in the control group). Some patients nevertheless presented serious side effects following the injections: two people were hospitalized, two had to go to the emergency room.

Akiko Iwasaki’s team, professor of immunology at Yale University, conducted a study with the American patient group Survivor Corps, not yet published, which shows similar results. “The vaccine may help the immune system fight and remove virus residues that persist in the body. Or the vaccine could stop a harmful immune response ”, suggests Akiko Iwasaki on the Yale University website, while adding that « at this stage these are only hypotheses ”.

“Judge on a case by case basis”

Results were also presented by Professor Dominique Salmon-Céron at the European Congress of Clinical Microbiology and Infectious Diseases which took place at the end of July. Out of a hundred patients with a long Covid and vaccinated, 35% of people see a transient reactivation of their symptoms of long Covid … But after two weeks, around 25% of patients have improved. “The vaccine could alleviate these symptoms by regulating an inappropriate immune response”, indicate these preliminary results.

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