Antibody response to vaccination against SARS-CoV2 and protection from the infection

MOLINERI A; VEAUTE C; GARCIA MI; BOTTASSO O; FLOR N; MIOTTI C; DIEZ C

Mar del Plata

Congreso; LXX Reunión Anual de la SAI, 16-19 noviembre de 2022; 2022

Sociedad Argentina de Inmunología

This study aimed to assess the response to vaccination against SARs-CoV2 in the FBCB-UNL community. 188 individuals (53 male, 135 females, aged 18-67 ys) were recruited from December 2021 to July 2022, and 3 blood samples were taken 1 month apart. Demographic and epidemiological data were registered for each sampling time. Anti-S antibody concentration (UI/mL) was quantitated by ELISA. Anti-N antibody levels were measured by ECLIA and expressedas Positivity Ratio (PR). A PR>1 indicates exposure to the antigen and was used to diagnose previous infections. Statistical analysis was done using a generalized linear mixed model and non-parametric tests. Most of the participants had two (49%) or three (50%) doses of the SARS-CoV2 vaccine at the start of the study. Only 1% received no dose either before or during the study. At the end of the project, 20% of the participants had two, 69% three, and 10% four doses. Regarding the first two doses, 72 individuals received Sinopharm, 71 Astrazeneca, 39 Sputnik V, 1 Moderna, and 2 Pfizer, with no significant differences in the levels of anti-S antibodies among the different schedules. In the third and fourth doses, Moderna and Pfizer predominated, followed by Astrazeneca, Sputnik, and Johnson & Johnson in descending order. Although individuals who hadtwo doses maintained positive anti-S antibody levels 5-6 months after the last dose, such values were significantly lower than the ones seen after 30-60 days among those receiving the third dose(p