The Institut Pasteur and the CHU de Strasbourg conducted a study with 160 volunteer caregivers from two Strasbourg hospitals. These personnel had all been tested positive for Covid-19 thanks to virological tests and suffering from mild forms of the disease. The goal was to find out if these patients had developed antibodies.
“We knew that people with severe forms of the disease developed antibodies within 15 days of the onset of signs, said in a statement Arnaud Fontanet, one of the study authors and head of the Department of Global Health at Institut Pasteur. We now know that this is also true for those who have minor forms, even if the antibody levels are probably lower. ”
“Protection against a new infection”
The results of the study, published on Saturday, show that almost all of these people developed antibodies within 15 days of the start of the infection. A rapid immunodiagnostic test detected antibodies in 153 of 160 samples and up to 159 in the S-Flow test, developed by the Pasteur Institute.
“Our study shows that the levels of antibodies are, in most cases, compatible with protection against a new infection with SARS-CoV-2, at least up to 40 days after the onset of signs,” adds Olivier Schwartz , head of the Virus and immunity unit at Pasteur.
Finally, another test was used to determine whether these patients had “neutralizing antibodies”, that is, able to protect them from the virus. Result: 28 days after the onset of symptoms, 98% of patients had developed these famous neutralizing antibodies.
For how long ?
The question now is whether this protection is durable. According to Samira Fafi Kremer, of the Institute of virology of the CHU of Strasbourg and one of the authors of the study, “there is still an uncertainty”. Some patients still have these antibodies up to 40 days after the onset of symptoms, “now we need to check that they persist over time.” For this, a follow-up of the patients is necessary, “for at least a year”, continues the professor on the antenna of LCI.
The latter also specifies that, despite the presence of these neutralizing antibodies, “we can remain contagious”. We must therefore be careful to respect barrier gestures anyway.
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