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Antibodies directed against the spike protein of the Covid-19 virus persist “up to 13 months after infection”, according to a study from the Strasbourg University Hospital (France) unveiled on Thursday, which has not yet been published in a journal scientist.
An Italian study published in early May announced that antibodies neutralizing Covid-19 remained in the blood for at least eight months after infection.
The Strasbourg study, led in particular by biologist Floriane Gallais and led by Professor Samira Fafi-Kremer, followed 1,309 people for more than a year, 393 of whom had already contracted Covid-19.
Of the latter group, “one year after infection, 97% of individuals have kept their anti-S antibodies”, directed against the spike protein, a point on the surface of the virus which allows it to attack human cells, indicates a press release from the CHU.
By comparing the number of re-infections that occurred during the study in this group with the number of new infections in the control group of 916 people, the researchers calculate that the risk of contracting the disease is “reduced by 96.7 % in formerly infected people ”, thanks to“ the long-term persistence of anti-S antibodies ”.
The scientists also noted that, thirteen months later, the concentration of these antibodies in the body makes it possible to neutralize “the wild virus (the initial form of the virus, note) and the British variant, but not the South African”.
The study emphasizes that vaccination, even at a single dose, “strengthens protection against variants by significantly increasing” the amounts of antibodies.
“This study carried out on a large cohort provides crucial information on the persistence of antibodies and on the risk of reinfection,” said Samira Fafi-Kremer, quoted in the press release. “We plan to extend the study to continue the follow-up at 18 months and 24 months to better assess the dynamics of the antibodies over the long term.”
The study also showed that antibodies to the virus’s spike protein “drop faster in men than in women.”
The study was pre-published without peer review on the medrxiv.org website.
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