Comparative analysis of antibody responses to BNT162b2, ChAdOx1, and CoronaVac vaccines in the Albanian population over the pandemic years 2021 to 2022

Abstract

This repeated cross-sectional study with two independent sample populations compared the antibody response to severe acute respiratory syndrome coronavirus 2 vaccines in Albania in July-August 2021 and 2022. In 2021, it found higher anti-spike-1 seropositivity and antibody levels in fully vaccinated individuals, especially with BNT162b2 and ChAdOx1 and to a lesser degree with CoronaVac. By 2022, all single-dose recipients showed high antibody responses, suggesting natural infection-enhanced immunity. The study indicates a significant evolution in the antibody response to different coronavirus disease 2019 vaccines and suggests that a single vaccine dose, coupled with natural infection, might suffice to maintain adequate immunity levels in an endemic scenario.

Keywords: Albanian people; Anti-nucleoprotein immunoglobulin G; Anti-spike-1 immunoglobulin G; COVID-19 vaccines; SARS-CoV2 antibodies.

Fig. 1. Anti-spike-1-SARS-CoV-2 seropositivity rates (%) (A) and antibody levels (index ratio) (B) in individuals with different vaccine types studied in August 2021. Statistical p-values are shown in the boxes above the charts. SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.

Fig. 2. Anti-spike-1-SARS-CoV-2 seropositivity rates (%) (A) and antibody levels (index ratio) (B) in individuals with different vaccine types studied in August 2022. Statistical p-values are shown in the boxes above the chart. SARS-CoV-2, severe acute respiratory syndrome coronavirus 2.