The role of COVID-19 survivor status and gender towards neutralizing antibody titers 1, 2, 3 months after sinovac vaccine administration on clinical year medical student in Indonesia.

Background Sinovac was the first vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) used in Indonesia. However, data regarding the effects of certain variables such as clinical demographic on antibody levels in individuals vaccinated with Sinovac are scarce. We aimed to investigate the impact of gender and previous SARS-CoV-2 infection status on neutralizing antibody titers 1, 2, and 3 months after the administration of Sinovac vaccine. Method A cross-sectional study was conducted from February to May 2021. Data on neutralizing antibody levels, previous SARS-CoV-2 infection status, and gender were retrieved from the monthly quantitative serology evaluation database of Siloam Hospitals Lippo Village, Tangerang, Indonesia. The role of each variable was analyzed using the t-test or Mann-Whitney U test depending on data distribution. Result Data from 350 participants were collected for the study. Participants with a history of positive SARS-CoV-2 RT-PCR test had significantly higher neutralizing antibody titers in the first (144 U/mL, p = 0.036) and second month (144 U/mL, p = 0.005) after vaccination compared to those without history of positive RT-PCR test. Female participants also had significantly higher neutralizing antibody titers in the first, second, and third month (43 U/mL, 42 U/mL, and 39 U/mL, respectively; p = 0.001, 0.002, and 0.003, respectively) after vaccination compared to male. Conclusion COVID-19 survivor status and the female gender are associated with higher neutralizing antibody titers after Sinovac vaccine administration.