Browsing by Author "Rivera Pérez, Daniela"

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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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    Interim report: Safety and immunogenicity of an inactivated vaccine against SARS-CoV-2 in healthy chilean adults in a phase 3 clinical trial
    (2021) Bueno Ramírez, Susan; Abarca Villaseca, Katia; González Adonis, Pablo Andrés; Gálvez Arriagada, Nicolás Marcelo Salvador; Soto Ramírez, Jorge Andrés; Duarte Peñaloza, Luisa Fernanda; Schultz Lombardic, Bárbara M.; Pacheco, Gaspar A.; González Carreño, Liliana Andrea; Vázquez, Yaneisi; Ríos Raggio, Mariana; Melo González, Felipe; Rivera Pérez, Daniela; Iturriaga, Carolina; Urzúa Acevedo, Marcela del Pilar; Domínguez De Landa, María Angélica; Andrade Parra, Catalina Andrea; Berríos Rojas, Roslye; Canedo Marroquín, Giselda; Covián, Camila
    The ongoing COVID-19 pandemic has had a significant impact worldwide, with an incommensurable social and economic burden. The rapid development of safe and protective vaccines against this disease is a global priority. CoronaVac is a vaccine prototype based on inactivated SARS-CoV-2, which has shown promising safety and immunogenicity profiles in pre-clinical studies and phase 1/2 trials in China. To this day, four phase 3 clinical trials are ongoing with CoronaVac in Brazil, Indonesia, Turkey, and Chile. This article reports the safety and immunogenicity results obtained in a subgroup of participants aged 18 years and older enrolled in the phase 3 Clinical Trial held in Chile.