[Immunogenicity and adverse events of SARS-CoV-2 vaccine in health workers].

Introduction: The aim of this study was to evaluate the adverse effects and immune response associated with IgG anti S1 SAEA-CoV-2 antibodies among healthcare workers at Señor del Milagro Hospital in Salta city, after receiving two doses of COVID-19 vaccine.

Methods: A prospective cohort study was carried out from March 2021 to April 2022. Demographic, clinical data, adverse events supposedly attributed to vaccination (AEFIs) were collected and two samples were taken to measure serum antibody levels.

Results: 408 volunteers participated, 401 (98%) were vaccinated with Sputnik-V. The average age was 45.5 years with a predominance of the female sex (71%). AEFIs were reported in 188 (46.1%) and 121 (29.7%) after the first and second doses respectively (p<0.001). These events were mostly mild and transient, more frequent after the first dose. The first antibody test was positive in 99% with a mean titer of 9.7 (SD 3.7). The second dosage was positive in 88% with a mean titer of 6.4 (SD 4.4). Participants with a history of infection and previous positive testing showed significantly higher antibody titers (p<0.001).

Conclusion: The AEFIs reported were mostly mild and transient. Mass vaccination and administration of the recommended dose are essential to achieve effective herd immunity. The majority of vaccinated healthcare workers developed antibodies and those who had the disease prior to vaccination had significant antibody titers.