Browsing by Author "Mora, Judith"

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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 immune response induced by two immunization schedules with an inactivated SARS-CoV-2 vaccine in a randomized phase 3 clinical trial
    (2022) Galvez Arriagada, Nicolás Marcelo Salvador; Pacheco Ruidiaz, Gaspar Andrés; Schültz Lombardic, Barbara Melinka; Melo González, Felipe Andrés; Soto Ramírez, Jorge Andrés; Duarte Peñaloza, Luisa Fernanda; González Carreño, Liliana Andrea; Rivera Pérez, Daniela Belén; Ríos Raggio, Mariana; Berríos, Roslye V.; Vazquéz Hernandéz, Yaneisi; Moreno Tapia, Daniela Paz; Vallejos Galvez, Omar Patricio; Andrade Parra, Catalina Andrea; Hoppe Elsholz, Guillermo; Iturriaga, Carolina; Urzua, Marcela; Navarrete, María S.; Rojas González, Álvaro Miguel; Fasce Pineda, Rodrigo Andrés; Fernández, Jorge; Mora, Judith; Ramírez, Eugenio; Gaete Argel, Aracelly; Acevedo Blanco, Mónica Andrea; Valiente Echeverría, Fernando; Soto Rifo, Ricardo; Weiskopf, Daniela; Grifoni, Alba; Sette, Alessandro; Zeng, Gang; Meng, Weining; González Aramundiz, José Vicente; Goldblatt, David; Acuna González, Pablo Ernesto; Abarca Villaseca, Katia; Bueno Ramírez, Susan Marcela; Kalergis Parra, Alexis Mikes
    Background: The development of vaccines to control the COVID-19 pandemic progression is a worldwide priority. CoronaVac® is an inactivated 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 ≥18 years. Volunteers received two doses of CoronaVac® separated by two (0-14 schedule) or four weeks (0-28 schedule). 2,302 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 between schedules. Stimulation of PBMCs with MPs induced the secretion of IFN-γ and the expression of activation induced markers for both schedules. Correlation matrixes showed strong correlations between neutralizing antibodies and IFN-γ 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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    Immune responses during COVID-19 breakthrough cases in vaccinated children and adolescents
    (Frontiers Media SA, 2024) Rivera Pérez, Daniela; Méndez Vejar, Constanza Soledad; Diethelm Varela, Benjamín Manuel; Melo González, Felipe Andrés; Vázquez Hernández, Yaneisi; Meng, Xing; Xin, Qianqian; Fasce, Rodrigo A.; Fernández, Jorge; Mora, Judith; Ramírez, Eugenio; Acevedo, Mónica L.; Valiente Echeverria, Fernando; Soto Rifo, Ricardo; Grifoni, Alba; Weiskopf, Daniela; Sette, Alessandro; Astudillo Paredes, Patricio Andrés; Le Corre Pérez, Monique Nicole; Abarca Villaseca, Katia; Perret Pérez, Cecilia; González Muñoz, Pablo Alberto; Soto Ramírez, Jorge Andrés; Bueno Ramírez, Susan; Kalergis, Alexis M.
    Background: Vaccine effectiveness against SARS-CoV-2 infection has been somewhat limited due to the widespread dissemination of the Omicron variant, its subvariants, and the immune response dynamics of the naturally infected with the virus. Methods: Twelve subjects between 3-17 years old (yo), vaccinated with two doses of CoronaVac®, were followed and diagnosed as breakthrough cases starting 14 days after receiving the second dose. Total IgGs against different SARS-CoV-2 proteins and the neutralizing capacity of these antibodies after infection were measured in plasma. The activation of CD4+ and CD8+ T cells was evaluated in peripheral blood mononuclear cells stimulated with peptides derived from the proteins from the wild-type (WT) virus and Omicron subvariants by flow cytometry, as well as different cytokines secretion by a Multiplex assay. Results: 2 to 8 weeks post-infection, compared to 4 weeks after 2nd dose of vaccine, there was a 146.5-fold increase in neutralizing antibody titers against Omicron and a 38.7-fold increase against WT SARS-CoV-2. Subjects showed an increase in total IgG levels against the S1, N, M, and NSP8 proteins of the WT virus. Activated CD4+ T cells showed a significant increase in response to the BA.2 subvariant (p<0.001). Finally, the secretion of IL-2 and IFN-γ cytokines showed a discreet decrease trend after infection in some subjects. Conclusion: SARS-CoV-2 infection in the pediatric population vaccinated with an inactivated SARS-CoV-2 vaccine produced an increase in neutralizing antibodies against Omicron and increased specific IgG antibodies for different SARS-CoV-2 proteins. CD4+ T cell activation was also increased, suggesting a conserved cellular response against the Omicron subvariants, whereas Th1-type cytokine secretion tended to decrease. Clinical Trial Registration: clinicaltrials.gov #NCT04992260
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    Seroprevalence study of infection with influenza A (H1N1)pdm09 virus in San Felipe Town, Chile
    (2013) Olea, Andrea; Fasce, Rodrigo; Aguilera, Ximena; Oliva, Otavio; Muñoz, Sergio; García, Maritza; Pedroni, Elena; Nájera, Manuel; Cerda, Jaime; Abarca Villaseca, Katia; Guerrero, Andrea; Bustos, Patricia; Mora, Judith; Vega, Jeanette; Mccarron, Meg; Widdowson, Marc-Alain; Castillo, E. R.