Along with their level of protection against
COVID-19, SARS-CoV-2-specific
antibodies decline over time following vaccination with
BNT162b2. However, relevant data on
AZD1222 are scarce. In this context, the aim of this study was to compare SARS-CoV-2
neutralizing antibody (NAb) levels at one, three and six months after second vaccination with the
BNT162b2 mRNA vaccine and the ChAdOx1 (
AZD1222) viral vector
vaccine (NCT04743388). The measurements were performed with the GenScript's cPassTM SARS-CoV-2 NAbs Detection Kit (GenScript, Inc.; Piscataway, NJ, USA). Overall, data from 282 individuals were included (
BNT162b2 n = 83,
AZD1222 n = 199). Both
vaccines induced strong NAbs responses at 1 month following vaccination. Interestingly, NAb activity seemed superior with
BNT162b2 compared with
AZD1222. A gradual decline in NAbs titers was evident at 3 and 6 months post vaccination with both
vaccines. However, the superiority of NAb response with
BNT162b2 over
AZD1222 remained consistent at all time points examined. Furthermore, the elimination rate of the NAb titer was higher throughout during the study period for those vaccinated with
AZD1222 compared with
BNT162b2. Age, gender, body mass index or comorbidities did not have a significant impact on NAbs levels over time. Our results may inform public health policies regarding the timing of booster
COVID-19 vaccine shots.