Assessing the long-stand antibody response induced by COVID-19vaccines: A study in an educational cohort in San Luis, Argentina

ELIÇABE, JAVIER; LEPORATI, MARIANELA; GORLINO, CAROLINA; VITALE, PATRICIA; DISTEL, MATIAS; SILVA, JUAN; FUNES, SAMANTA; JOFRE, BRENDA; ARIAS, JOSÉ LUIS; VELAZQUEZ, MARISOL

VACCINE

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2022

0264-410X

Background:Although there has developed an increased interest in the vaccines BNT1622b2 (Pfizer/BioNTech), mRNA-1273 (Moderna/NIAID), and ChAdOx1 nCoV-19 (AstraZeneca/University of Oxford),there are still few reports describing the immune response induced by different vaccine platforms inreal-world settings of low-income countries. Here, we proposed to analyse the humoral immuneresponse elicited by the primary vaccines used in Argentina from July-December 2021.Methods:Anti-SARS-CoV-2-Spike-RBD IgG and neutralising antibodies were assayed by ELISA in a total of871 serum samples obtained from 376 volunteers from an educational staff. The individuals were vacci-nated with BBIBP-CorV (Sinopharm), ChAdOx1 nCoV-19 (AstraZeneca/University of Oxford, AZ), Gam-COVID-Vac (Sputnik V, SpV) or combined vaccines (mostly SpV and mRNA-1273, Moderna). The antibodyresponse was analysed several days after the initial vaccination (20, 40, 120 and 180 days).Results:After receiving at least one dose of the COVID-19 vaccine, we detected 93.34% of seroprevalence.Previously SARS-CoV-2 infected showed higher antibody concentrations compared with naïve vaccinees.Six months after the initial vaccination, combined vaccination induced higher anti-SARS-CoV-2 antibodylevels than the other vaccines in naïve volunteers. However, we did not find differences in the neutralis-ing responses after any vaccine from naïve vaccines or between the naïve and previously infected volun-teers on day 120 after vaccination.Conclusions:Our long-term analysis of volunteers from the educational system provides data in a real-world context, showing the benefits of a boost dose still in previously infected volunteers, and suggestingthe advantages of a heterologous prime-boost schedule.