Browsing by Author "Gaete-Argel, Aracelly"

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    A Booster Dose of CoronaVac Increases Neutralizing Antibodies and T Cells that Recognize Delta and Omicron Variants of Concern
    (2022) Schultz, Barbara M.; Melo-Gonzalez, Felipe; Duarte, Luisa F.; Galvez, Nicolas M. S.; Pacheco, Gaspar A.; Soto, Jorge A.; Berrios-Rojas, Roslye, V; Gonzalez, Liliana A.; Moreno-Tapia, Daniela; Rivera-Perez, Daniela; Rios, Mariana; Vazquez, Yaneisi; Hoppe-Elsholz, Guillermo; Andrade-Parra, Catalina A.; Vallejos, Omar P.; Pina-Iturbe, Alejandro; Iturriaga, Carolina; Urzua, Marcela; Navarrete, Maria S.; Rojas, Alvaro; Fasce, Rodrigo; Fernandez, Jorge; Mora, Judith; Ramirez, Eugenio; Gaete-Argel, Aracelly; Acevedo, Monica; Valiente-Echeverria, Fernando; Soto-Rifo, Ricardo; Weiskopf, Daniela; Grifoni, Alba; Sette, Alessandro; Zeng, Gang; Meng, Weining; Gonzalez-Aramundiz, Jose, V; Gonzalez, Pablo A.; Abarca, Katia; Kalergis, Alexis M.; Bueno, Susan M.
    CoronaVac is an inactivated SARS-CoV-2 vaccine approved by the World Health Organization (WHO). Previous studies reported increased levels of neutralizing antibodies and specific T cells 2 and 4 weeks after two doses of CoronaVac; these levels were significantly reduced at 6 to 8 months after the two doses. Here, we report the effect of a booster dose of CoronaVac on the anti-SARS-CoV-2 immune response generated against the variants of concern (VOCs), Delta and Omicron, in adults participating in a phase III clinical trial in Chile. Volunteers immunized with two doses of CoronaVac in a 4-week interval received a booster dose of the same vaccine between 24 and 30 weeks after the second dose. Neutralization capacities and T cell activation against VOCs Delta and Omicron were assessed 4 weeks after the booster dose. We observed a significant increase in neutralizing antibodies 4 weeks after the booster dose. We also observed a rise in anti-SARS-CoV-2-specific CD4(+) T cells over time, and these cells reached a peak 4 weeks after the booster dose. Furthermore, neutralizing antibodies and SARS-CoV-2-specific T cells induced by the booster showed activity against VOCs Delta and Omicron. Our results show that a booster dose of CoronaVac increases adults' humoral and cellular anti-SARS-CoV-2 immune responses. In addition, immunity induced by a booster dose of CoronaVac is active against VOCs, suggesting adequate protection. IMPORTANCE CoronaVac is an inactivated vaccine against SARS-CoV-2 that has been approved by WHO for emergency use. Phase III clinical trials are in progress in several countries, including China, Brazil, Turkey, and Chile, and have shown safety and immunogenicity after two doses of the vaccine. This report characterizes immune responses induced by two doses of CoronaVac followed by a booster dose 5 months after the second dose in healthy Chilean adults. The data reported here show that a booster dose increased the immune responses against SARS-CoV-2, enhancing levels of neutralizing antibodies against the ancestral strain and VOCs. Similarly, anti-SARS-CoV-2 CD4(+) T cell responses were increased following the booster dose. In contrast, levels of gamma interferon secretion and T cell activation against the VOCs Delta and Omicron were not significantly different from those for the ancestral strain. Therefore, a third dose of CoronaVac in a homologous vaccination schedule improves its immunogenicity in healthy volunteers.
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    Differences in the immune response elicited by two immunization schedules with an inactivated SARS-CoV-2 vaccine in a randomized phase 3 clinical trial
    (2022) Galvez, Nicolas M. S.; Pacheco, Gaspar A.; Schultz, Barbara M.; Melo-Gonzalez, Felipe; Soto, Jorge A.; Duarte, Luisa F.; Gonzalez, Liliana A.; Rivera-Perez, Daniela; Rios, Mariana; Berrios, Roslye, V; Vazquez, Yaneisi; Moreno-Tapia, Daniela; Vallejos, Omar P.; Andrade, Catalina A.; Hoppe-Elsholz, Guillermo; Iturriaga, Carolina; Urzua, Marcela; Navarrete, Maria S.; Rojas, Alvaro; Fasce, Rodrigo; Fernandez, Jorge; Mora, Judith; Ramirez, Eugenio; Gaete-Argel, Aracelly; Acevedo, Monica L.; Valiente-Echeverria, Fernando; Soto-Rifo, Ricardo; Weiskopf, Daniela; Grifoni, Alba; Sette, Alessandro; Zeng, Gang; Meng, Weining; Gonzalez-Aramundiz, Jose, V; Johnson, Marina; Goldblatt, David; Gonzalez, Pablo A.; Abarca, Katia; Bueno, Susan M.; Kalergis, Alexis M.
    Background: The development of vaccines to control the coronavirus disease 2019 (COVID-19) pandemic progression is a worldwide priority. CoronaVac is an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine approved for emergency use with robust efficacy and immunogenicity data reported in trials in China, Brazil, Indonesia, Turkey, and Chile. Methods: This study is a randomized, multicenter, and controlled phase 3 trial in healthy Chilean adults aged & GE;18 years. Volunteers received two doses of CoronaVac separated by 2 (0-14 schedule) or 4 weeks (0-28 schedule); 2302 volunteers were enrolled, 440 were part of the immunogenicity arm, and blood samples were obtained at different times. Samples from a single center are reported. Humoral immune responses were evaluated by measuring the neutralizing capacities of circulating antibodies. Cellular immune responses were assessed by ELISPOT and flow cytometry. Correlation matrixes were performed to evaluate correlations in the data measured. Results: Both schedules exhibited robust neutralizing capacities with the response induced by the 0-28 schedule being better. No differences were found in the concentration of antibodies against the virus and different variants of concern (VOCs) between schedules. Stimulation of peripheral blood mononuclear cells (PBMCs) with Mega pools of Peptides (MPs) induced the secretion of interferon (IFN)-gamma and the expression of activation induced markers in CD4(+) T cells for both schedules. Correlation matrixes showed strong correlations between neutralizing antibodies and IFN-gamma secretion. Conclusions: Immunization with CoronaVac in Chilean adults promotes robust cellular and humoral immune responses. The 0-28 schedule induced a stronger humoral immune response than the 0-14 schedule.
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    Differential neutralizing antibody responses elicited by CoronaVac and BNT162b2 against SARS-CoV-2 Lambda in Chile
    (2022) Acevedo, Monica L.; Gaete-Argel, Aracelly; Alonso-Palomares, Luis; de Oca, Marco Montes; Bustamante, Andres; Gaggero, Aldo; Paredes, Fabio; Cortes, Claudia P.; Pantano, Sergio; Martinez-Valdebenito, Constanza; Angulo, Jenniffer; Le Corre, Nicole; Ferres, Marcela; Navarrete, Marcelo A.; Valiente-Echeverria, Fernando; Soto-Rifo, Ricardo
    The SARS-CoV-2 Lambda variant has been prevalent in Latin America. An analysis of the neutralization capacity of antibodies elicited by CoronaVac and BNT162b2 against SARS-CoV-2 Lambda in plasma from healthcare workers and patients in Chile reveals that BNT162b2 elicits higher neutralizing antibody titres than CoronaVac.
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    Impact of homologous and heterologous boosters in neutralizing antibodies titers against SARS-CoV-2 Omicron in solid-organ transplant recipients
    (2023) Gaete-Argel, Aracelly; Saavedra-Alarcon, Vicente; Saure, Denis; Alonso-Palomares, Luis; Acevedo, Monica L.; Alarcon, Marion; Bueno, Susan M.; Kalergis, Alexis M.; Soto-Rifo, Ricardo; Valiente-Echeverria, Fernando; Cortes, Claudia P.
    IntroductionBooster doses of SARS-CoV-2 vaccines improve seroconversion rates in solid organ transplant recipients (SOTRs) but the impact of homologous and heterologous booster doses in neutralizing antibody (NAb) titers and their ability to interfere with the variant of concern Omicron are not well studied. MethodsWe designed a prospective, open-label, observational clinical cohort study. 45 participants received two doses of BNT162b2 or CoronaVac (21-day or 28-day intervals, respectively) followed by a first and second booster with BNT162b2 (5-month apart each) and we analyzed the neutralizing antibody titers against SARSCoV-2 D614G (B.1 lineage) and Omicron (BA.1 lineage). ResultsOur results show that SOTRs receiving an initial two-dose scheme of CoronaVac or BNT162b2 generate lower NAbs titers against the ancestral variant of SARS-CoV-2 when compared with healthy controls. Although these NAb titers were further decreased against the SARS-CoV-2 Omicron, a single BNT162b2 booster in both groups was sufficient to increase NAb titers against the variant of concern. More importantly, this effect was only observed in those participants responding to the first two shots but not in those not responding to the initial vaccination scheme. DiscussionThe data provided here demonstrate the importance of monitoring antibody responses in immunocompromised subjects when planning booster vaccination programs in this risk group.
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    Neutralizing antibodies induced by homologous and heterologous boosters in CoronaVac vaccines in Chile
    (2023) Acevedo, Johanna; Acevedo, Monica L.; Gaete-Argel, Aracelly; Araos, Rafael; Gonzalez, Cecilia; Espinoza, Daniela; Rivas, Solange; Pizarro, Pablo; Jarpa, Stephan; Soto-Rifo, Ricardo; Jara, Alejandro; Valiente-Echeverria, Fernando
    Objectives: To determine the impact of a booster dose on the humoral response in individuals inoculated with a complete schedule of any SARS-CoV-2 vaccine, we evaluated the neutralizing antibody (NAb) titres of homologous or heterologous booster doses over a 90-days period in CoronaVac vaccinees from 3 centres in Santiago, Chile.