AUTHOR=Escobar Alejandro , Reyes-López Felipe E. , Acevedo Mónica L. , Alonso-Palomares Luis , Valiente-Echeverría Fernando , Soto-Rifo Ricardo , Portillo Hugo , Gatica Jimena , Flores Ivan , Nova-Lamperti Estefanía , Barrera-Avalos Carlos , Bono María Rosa , Vargas Leonardo , Simon Valeska , Leiva-Salcedo Elias , Vial Cecilia , Hormazabal Juan , Cortes Lina Jimena , Valdés Daniel , Sandino Ana M. , Imarai Mónica , Acuña-Castillo Claudio TITLE=Evaluation of the Immune Response Induced by CoronaVac 28-Day Schedule Vaccination in a Healthy Population Group JOURNAL=Frontiers in Immunology VOLUME=12 YEAR=2022 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.766278 DOI=10.3389/fimmu.2021.766278 ISSN=1664-3224 ABSTRACT=

CoronaVac vaccine from Sinovac Life Science is currently being used in several countries. In Chile, the effectiveness of preventing hospitalization is higher than 80% with a vaccination schedule. However, to date, there are no data about immune response induction or specific memory. For this reason, we recruited 15 volunteers without previous suspected/diagnosed COVID-19 and with negative PCR over time to evaluate the immune response to CoronaVac 28 and 90 days after the second immunization (dpi). The CoronaVac administration induces total and neutralizing anti-spike antibodies in all vaccinated volunteers at 28 and 90 dpi. Furthermore, using ELISpot analysis to assay cellular immune responses against SARS-CoV-2 spike protein, we found an increase in IFN-gamma- and Granzyme B-producing cells in vaccinated volunteers at 28 and 90 dpi. Together, our results indicate that CoronaVac induces a robust humoral immune response and cellular immune memory of at least 90 dpi.