Study of the humoral immune response against SARS-CoV-2 post-infectious and post-vaccination

COVID-19 remains an emerging disease that continues to challenge our immuno virological knowledge Thus, to better understand the pathophysiology of the infection it seemed urgent to us to define the place of serological tests and immunological investigations in the medium and long term monitoring of patients, in particular the monitoring of cohorts of infected and vaccinated subjects. Our study included 509 patients of different sexes with 206 patients infected with SARS-CoV-2,254 patients vaccinated against SARS-CoV-2(sputnik=169, sinovac=85)and 49 patients (hybrid group) at the both vaccinated and infected. The clinical signs mainly found in infected and infected vaccinated patients are asthenia, fever, dry cough, headaches, anosmia, ageusia with mainly benign forms. The most frequently observed adverse reactions in vaccinated patients and the hybrid group are:asthenia, fever, body aches, chills, headache and pain at the injection site. The majority of infected and vaccinated patients had a high viral load, and the most frequent comorbidities in the three groups are hypertension, diabetes, asthma. Analysis of the kinetics of anti-SARS-CoV-2 antibodies shows that infected and vaccinated patients have higher antibody levels than those in other groups. In addition, these antibody levels are maintained high until the 9th month while these kinetics decrease from the 3rd month in the group infected or vaccinated alone. Our data show that anti-SARS-CoV-2 antibody responses persist for at least 3 months after symptom onset and that IgG levels remain relatively stable during the post-convalescence period in COVID-19 patients.