Background
Vaccination constitutes the best strategy against COVID-19. In Tunisia, seven vaccines standing for the three main platforms, namely RNA, viral vector, and inactivated vaccines, have been used to vaccinate the population at a large scale. This study aimed to assess, in our setting, the kinetics of vaccine-induced anti-RBD IgG and IgA antibody responses.
Conclusions
After following up for 12 months post-immunization, we concluded that the hierarchy between the platforms for anti-RBD antibody-titer dynamics was RNA vaccines, followed by viral-vector and alum-adjuvanted inactivated vaccines.
Methods
Using in-house developed and validated ELISA assays, we measured anti-RBD IgG and IgA serum antibodies in 186 vaccinated workers at the Institut Pasteur de Tunis over 12 months.
Results
We showed that RNA vaccines were the most immunogenic vaccines, as compared to alum-adjuvanted inactivated and viral-vector vaccines, either in SARS-CoV-2-naïve or in SARS-CoV-2-experienced individuals. In addition to the IgG antibodies, the vaccination elicited RBD-specific IgAs. Vaccinated individuals with prior SARS-CoV-2 infection exhibited more robust IgG and IgA antibody responses, as compared to SARS-CoV-2-naïve individuals. Conclusions: After following up for 12 months post-immunization, we concluded that the hierarchy between the platforms for anti-RBD antibody-titer dynamics was RNA vaccines, followed by viral-vector and alum-adjuvanted inactivated vaccines.