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Une nouvelle étude sur le personnel et les élèves d'un lycée de l'Oise, où a émergé le premier groupe de cas Covid-19 en France, a conclu que si les mesures de confinement portaient leurs fruits, l'immunité de groupe était encore loin.
L'Institut Pasteur, ainsi que d'autres agences de santé publique, ont recruté des étudiants, des enseignants, du personnel non enseignant, des parents et des frères et sœurs d'étudiants pour l'étude.
The high school used in the study was in Crépy-en Valois, the same town where a 60-year-old teacher was diagnosed with a coronavirus in late February, before dying.
The preliminary results of the retrospective study conducted between March 30 and April 4 were released Thursday (English) and are awaiting peer review.
Participants completed a questionnaire covering the history of fever and / or respiratory symptoms since January 13, 2020 and had been tested for antibodies to the SARS-CoV-2 virus, which causes coronavirus disease.
Odor loss, taste of key symptoms
Among the 661 participants, the study found that only 171 were diagnosed positive – 25.9 percent.
Students, teachers and non-teaching staff at the school tested 40.9% higher than just 10.9% of parents and siblings.
The study also found that at least 17% of infected people had no symptoms, but if they did, it was mainly loss of smell (84.7%) and loss taste (88.1%).
Curiously, the study found that four times as many non-smokers were infected (28%), compared to only 7.2% of smokers, a finding that has echoed in other studies.
The long road to group vaccination
The researchers concluded that “the establishment of collective immunity will take time and that the lifting of containment measures in France will be long and complex”.
Figures from public health agencies in France suggest that only about 6% of the population will have developed antibodies to the virus before the birth is due on May 11.
This falls short of the figure of 60 to 70 percent that experts estimate is necessary for group vaccination.
For group immunity to be effective, it must be demonstrated that the antibodies protect their host for at least a few months. So far, there is no evidence that the antibodies are effective, according to Arnaud Fontanet, one of the study’s authors, and responsible for epidemiology at the Institut Pasteur.
He told RFI that group immunity will take some time, especially since “other regions of France are practically intact”.
However, he stressed the positive effects of confinement on the slowdown of the epidemic, particularly because of the February holidays and the previous closure of the Oise region on March 1, which he said was essential. to reduce the spread of the virus in the following weeks. .