COVID-19: Comparison of immunogenicity response between natural and post-vaccination infections

Abstract

Background: The COVID-19 pandemic in Indonesia has been ongoing for a year as at time of writing, since March 2020. Vaccination interventions are public health efforts that are arguably the most effective in the current pandemic situation, in addition to routine health protocols. Until now, there have been few reports of the effectiveness of vaccination and antibody titers formed after vaccination is carried out. This study aims to find out the difference in antibody titers after vaccination in confirmed COVID-19 cases. Methods: This observational study investigated the difference in SARS-Cov-2 quantitative antibody titers between two cohorts: unvaccinated COVID patients who were confirmed -with COVID-19 and individuals undergoing vaccination at the hospital Prof. dr. R. D. Kandou Manado. Inclusion and exclusion criteria, statistical analysis, and research ethics were applied in the study. Results: Antibody titers in survivor groups were relatively lower at 56 days and 84 days after COVID-19 diagnosis, while the antibody titer in the elderly group undergoing vaccination relatively increased at 56 days and 84 days after the first vaccination. There was a significant difference in antibody titers between a group of survivors and those who underwent vaccination on the first (28 days) and third (84 days). Conclusions: From this study, it was found that in the naturally COVID-19-infected group, antibody titers were still found for 84 days after COVID-19 diagnosis. In the group undergoing vaccination, it was found that antibody titers increased significantly at 56 days after vaccination.