Antibody Response after Second-Dose of Sputnik V, ChAdOxl-nCOV, and BBIBP-CorV in the Iranian General Population

Background: Effective and safe vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an important tool for controlling the COVID-19 pandemic. Emergency vaccination with Sputnik V, ChAdOx1-nCOV, and BBIBP-CorV candidate vaccines in Iran has started on February 17, 2021. Hence, in the current work, we compare anti-spike IgG responses in the general population following two vaccine doses with Sputnik V, ChAdOx1-nCOV, and BBIBP-CorV vaccines in Iran. Methods: We measured Anti-spike IgG responses using an Enzyme-linked immunosorbent assay among 165 healthy adult volunteers with no known history of COVID-19 aged 21–78 years in 21 days after the second dose of Sputnik V, ChAdOx1-nCOV, and BBIBP-CorV vaccines. The primary aim was to analyze anti-spike IgG response in three types of vaccines and its correlation to age, and sex. Results: Of the 165 participants, 151 (91.5%) had seropositivity for anti-spike IgG. The seropositivity rate of Sputnik V, ChAdOx1-nCOV and BBIBP-CorV recipients were 89.6%, 96.3 and 91.2, respectively, with a p-value of 0.588. The anti-spike IgG titre was higher among ChAdOx1-nCOV recipients (median 320 interquartile ranges (IQR) 110.3–320 Binding Antibody Units (BAU)/mL) than among Sputnik V (median 257.4 IQR 136.9–320 BAU/mL) and BBIBP-CorV (median 222.5 IQR 95.07–320 BAU/mL) recipients, but without significance (p = 0.377). Conclusions: Findings from this study demonstrate that the both anti-spike IgG titer and seropositivity rate were higher in ChAdOx1-nCOV recipients than in Sputnik V and BBIBP-CorV recipients. There was no notable difference in anti-spike IgG titer and seropositivity rate with regard to age, sex, and vaccine type.