Browsing by Author "Duarte, L.F."

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    An inactivated SARS-CoV-2 vaccine is safe and induces humoral and cellular immunity against virus variants in healthy children and adolescents in Chile
    (2022) Soto, J.A.; Melo-González, F.; Gutierrez-Vera, C.; Schultz, B.M.; Berríos-Rojas, R.V.; Rivera-Pérez, D.; Piña-Iturbe, A.; Hoppe-Elsholz, G.; Duarte, L.F.; Vázquez, Y.; Moreno-Tapia, D.; Ríos, M.; Palacios, P.A.; Garcia-Betancourt, R.; Santibañez, Á.; Mendez, C.; Diethelm-Varela, B.; Astudillo, P.; Calvo, M.; Cárdenas, A.; González, M.; Goldsack, M.; Gutiérrez, V.; Potin, M.; Schilling, A.; Tapia, L.I.; Twele, L.; Villena, R.; Grifoni, A.; Sette, A.; Weiskopf, D.; Fasce, R.A.; Fernández, J.; Mora, J.; Ramírez, E.; Gaete-Argel, A.; Acevedo, M.; Valiente-Echeverría, F.; Soto-Rifo, R.; Retamal-Díaz, A.; Muñoz-Jofré, N.; Meng, X.; Xin, Q.; Alarcón-Bustamante, E.; González-Aramundiz, J.V.; Le Corre, N.; Álvarez, M.J.; González, P.A.; Abarca, K.; Perret, C.; Carreño, L.J.; Kalergis, A.M.; Bueno, S.M.
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    Humoral and cellular response induced by a second booster of an inactivated SARS-CoV-2 vaccine in adults
    (2022) Melo González, Felipe; Méndez, Constanza; Peñaloza, H.F.; Schultz, B.M.; Piña Iturbe, A.; Ríos, M.; Moreno Tapia, D.; Pereira Sánchez, P.; Leighton, D.; Orellana, C.; Covarrubias, C.; Gálvez, N.M.S.; Soto, J.A.; Duarte, L.F.; Rivera Pérez, D.; Vázquez, Y.; Cabrera, A.; Bustos, S.; Iturriaga, C.; Urzua, M.; Navarrete, M.S.; Rojas, Á.; Fasce, R.; Fernández, J.; Mora, J.; Ramírez, E.; Gaete Argel, A.; Acevedo, M.; Valiente Echeverría, F.; Soto Rifo, R.; Weiskopf, D.; Grifoni, A.; Sette, A.; Zeng, G.; Meng, W.; González Aramundiz, J.V.; González, P.A.; Abarca, K.; Bueno, S.M.; Kalergis, A.M.
    The SARS-CoV-2 Omicron variant has challenged the control of the COVID-19 pandemic even in highly vaccinated countries. While a second booster of mRNA vaccines improved the immunity against SARS-CoV-2, the humoral and cellular responses induced by a second booster of an inactivated SARS-CoV-2 vaccine have not been studied. In the context of a phase 3 clinical study, we report that a second booster of CoronaVac® increased the neutralizing response against the ancestral virus yet showed poor neutralization against the Omicron variant. Additionally, isolated PBMCs displayed equivalent activation of specific CD4+ T cells and IFN-γ production when stimulated with a mega-pool of peptides derived from the spike protein of the ancestral virus or the Omicron variant. In conclusion, a second booster dose of CoronaVac® does not improve the neutralizing response against the Omicron variant compared with the first booster dose, yet it helps maintaining a robust spike-specific CD4+ T cell response.
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    Inactivated Vaccine-Induced SARS-CoV-2 Variant-Specific Immunity in Children
    (2022) Soto, J.A.; Melo-González, F.; Gutierrez-Vera, C.; Schultz, B.M.; Berríos-Rojas, R.V.; Rivera-Pérez, D.; Piña-Iturbe, A.; Hoppe-Elsholz, G.; Duarte, L.F.; Vázquez, Y.; Moreno-Tapia, D.; Ríos, M.; Palacios, P.A.; Garcia-Betancourt, R.; Santibañez, Á.; Pacheco, G.A.; Mendez, C.; Andrade, C.A.; Silva, P.H.; Diethelm-Varela, B.; Astudillo, P.; Calvo, M.; Cárdenas, A.; González, M.; Goldsack, M.; Gutiérrez, V.; Potin, M.; Schilling, A.; Tapia, L.I.; Twele, L.; Villena, R.; Grifoni, A.; Sette, A.; Weiskopf, D.; Fasce, R.A.; Fernández, J.; Mora, J.; Ramírez, E.; Gaete-Argel, A.; Acevedo, M.L.; Valiente-Echeverría, F.; Soto-Rifo, R.; Retamal-Díaz, A.; Muñoz-Jofré, N.; Meng, X.; Xin, Q.; Alarcón-Bustamante, E.; González-Aramundiz, J.V.; Le Corre, N.; Álvarez-Figueroa, M.J.; González, P.A.; Abarca, K.; Perret, C.; Carreño, L.J.; Bueno, S.M.; Kalergis, A.M.
    Multiple vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been evaluated in clinical trials. However, trials addressing the immune response in the pediatric population are scarce. The inactivated vaccine CoronaVac has been shown to be safe and immunogenic in a phase 1/2 clinical trial in a pediatric cohort in China. Here, we report interim safety and immunogenicity results of a phase 3 clinical trial for CoronaVac in healthy children and adolescents in Chile. Participants 3 to 17 years old received two doses of CoronaVac in a 4-week interval until 31 December 2021. Local and systemic adverse reactions were registered for volunteers who received one or two doses of CoronaVac. Whole-blood samples were collected from a subgroup of 148 participants for humoral and cellular immunity analyses. The main adverse reaction reported after the first and second doses was pain at the injection site. Four weeks after the second dose, an increase in neutralizing antibody titer was observed in subjects relative to their baseline visit. Similar results were found for activation of specific CD4+ T cells. Neutralizing antibodies were identified against the Delta and Omicron variants. However, these titers were lower than those for the D614G strain. Importantly, comparable CD4+ T cell responses were detected against these variants of concern. Therefore, CoronaVac is safe and immunogenic in subjects 3 to 17 years old, inducing neutralizing antibody secretion and activating CD4+ T cells against SARS-CoV-2 and its variants. (This study has been registered at ClinicalTrials.gov under no. NCT04992260.) IMPORTANCE This work evaluated the immune response induced by two doses of CoronaVac separated by 4 weeks in healthy children and adolescents in Chile. To date, few studies have described the effects of CoronaVac in the pediatric population. Therefore, it is essential to generate knowledge regarding the protection of vaccines in this population. Along these lines, we reported the anti-S humoral response and cellular immune response to several SARS-CoV-2 proteins that have been published and recently studied. Here, we show that a vaccination schedule consisting of two doses separated by 4 weeks induces the secretion of neutralizing antibodies against SARS-CoV-2. Furthermore, CoronaVac induces the activation of CD4+ T cells upon stimulation with peptides from the proteome of SARS-CoV-2. These results indicate that, even though the neutralizing antibody response induced by vaccination decreases against the Delta and Omicron variants, the cellular response against these variants is comparable to the response against the ancestral strain D614G, even being significantly higher against Omicron.