engleski

Qualitative and quantitative differences in SARS-CoV-2 - neutralizing antibody response induced by four COVID-19 vaccines or developed in COVID-19 convalescents

In the COVID-19 pandemic, we witnessed an impressive speed in the development of effective vaccines that have been approved for use in humans on the basis of the clinical studies comparing their efficacy to placebo. Head-to-head comparisons of several approved vaccines are rare, as well as comparisons of immune responses generated by vaccination to the ones created by the disease. Due to lack of appropriate standardization of assays that evaluate immune response, it is difficult to compare results from different studies. However, such analyses are inevitable in order to properly assess the correctness of epidemic measures applied in an effort to combat the pandemic. Here we report on a head-to head comparison of the first four vaccines authorized for emergency use in Europe (BNT162b2, mRNA-1273, AZD1222 or Ad26.COV2.S) in their ability to induce neutralizing antibody response (NT). All four deliver genetic information for the full-length spike protein into the host cells and induce both humoral and cellular branch of spike protein-specific immune response. Thus, NT response could serve as an indicator of the overall immune response induced by these vaccines. Well standardized wild-type neutralization assay1 enabled reliable comparison of antibody response induced by vaccines to the response induced in convalescents. By analysing the response in 113 vaccinees (≥18 per vaccine) we observed that the highest NTs were induced by mRNA vaccines, followed by AZD1222 and finally Ad26.COV2.S. In comparison to convalescents, these NTs were significantly higher, comparable and significantly lower, respectively. NT decline was significantly slower in convalescents. Better complement-activating properties of antibodies developed in natural infection as well as lower anti-spike IgG content in convalescents’ in comparison to vaccinees’ sera of comparable SARS-CoV-2 neutralisation power indicate that convalescents are armed with antibodies of additional specificities and/or classes, that contribute to SARS-CoV-2 neutralisation.

wild-type SARS-CoV-2 neutralization assay ; COVID-19 vaccines ; mRNA vaccine ; viral vector vaccines

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