Evaluation of the Immune Response Induced by CoronaVac 28-Day Schedule Vaccination in a Healthy Population Group
Alejandro Escobar, Felipe E. Reyes‐López, Mónica L. Acevedo, Luis Alonso-Palomares, Fernando Valiente‐Echeverría, Ricardo Soto‐Rifo, Hugo Portillo, Jimena Gatica, Iván Flores, Estefanía Nova‐Lamperti, Carlos Barrera‐Avalos, Marı́a Rosa Bono, Leonardo Vargas, Valeska Simon, Elías Leiva‐Salcedo, Cecilia Vial, Juan Hormazábal, Lina Jimena Cortes, Daniel Valdés, Ana María Sandino, Mónica Imarai, Claudio Acuña‐Castillo
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.