Comparison of immune response to various SARS-CoV-2 vaccines within 6 months after starting vaccination and following revaccination

Abstract

The pandemic of coronavirus infection (COVID-19) has stimulated the development, testing and widespread use of preventive vaccines based on various platforms. Our aim was to perform a direct comparison of immunogenicity of various vaccines within a single study in small groups within six months of SARS-CoV-2 vaccination and revaccination.
 The stdy group included subjects vaccinated with Sputnik V adenovirus vaccine, mRNA vaccines, and CoviVac whole-virion vaccine. Their immune status was assessed by enzyme immunoassay as specific antibody levels. Moreover, the neutralizing ability of detected antibodies was assessed using a cell test system based on pseudoviral technology.
 All of the mentioned vaccines were shown to elicit an immune response against SARS-CoV-2 RBD antigen, however, appropriate antibody titers and neutralizing capacities differed depending on the type of vaccine. The mRNA vaccines proved to be the most immunogenic, the effectiveness of the immune response to the Sputnik V adenovirus-based vaccine was lower. However, 6 months after vaccination, the effectiveness of virus neutralizing antibodies induced by these vaccines did not differ. The whole-virion CoviVac vaccine with proven efficiency by independent epidemiological studies, induced an antibody response against the RBD protein to a lesser extent.
 The seropositive participants of the study, both previously exposed to COVID-19 disease or vaccinated, exhibited high-titer production of antibodies already after the first dose of the Sputnik V vaccine, and a significantly higher antibody titer 6 months after the booster immunization as compared with initial level of antibodies, along with direct correlation between the antibody titers and their neutralizing activity.