Immunogenicity and Reactogenicity of CoronaVac: A Cohort Study

The ongoing COVID-19 pandemic remained a major public health concern despite large-scale deployment of vaccines. One the vaccines is CoronaVac, an inactivated vaccine. efficacy vaccine was estimated at 50.7–83.5% in clinical trials. However, real-world often differed. This study described CoronaVac post-vaccination reactogenicity and immunogenicity. Serum collected on days 0, 28, 56 84 from participants who received March–May 2021. Anti-SARS-CoV-2 Spike receptor binding domain measured using Elecsys® quantitative assay. Participants were interviewed for adverse events (AEs) one week after vaccination. Reported AEs fatigue, fever, runny nose, headache, muscle pain, pain injection site, paresthesia. Females reported more incidents than males. frequency similar between immunologically naïve pre-immune participants. In group, antibody titer 61.7 ± 84.2 U/mL (mean SD) day 28 increased to 99.3 91.9 56. peaked across all age groups, but reduction 18.0–26.3% observed 84. A titer-boosting effect with baseline 139.0 101.0 U/mL, which 206.7 77.4 steady until Hence, elicited response participants, mild AEs.