Examinando por Autor "Meng, Xing"

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    Different Safety Pattern of an Inactivated SARS-CoV-2 Vaccine (CoronaVac®) According to Age Group in a Pediatric Population from 3 to 17 Years Old, in an Open-Label Study in Chile
    (Multidisciplinary Digital Publishing Institute (MDPI), 2023-10) Le Corre, Nicole; Abarca, Katia; Astudillo, Patricio; Potin, Marcela; López, Sofía; Goldsack, Macarena; Valenzuela, Vania; Schilling, Andrea; Gaete, Victoria; Rubio, Lilian; Calvo, Mario; Twele, Loreto; González, Marcela; Fuentes, Daniela; Gutiérrez, Valentina; Reyes, Felipe; Tapia, Lorena I.; Villena, Rodolfo; Retamal-Díaz, Angello; Cárdenas, Antonio; Alarcón-Bustamante, Eduardo; Meng, Xing; Xin, Qianqian; González-Aramundiz, José V.; Álvarez-Figueroa, María Javiera; González, Pablo A.; Bueno, Susan M.; Soto, Jorge A.; Perret, Cecilia; Kalergis, Alexis M.
    During the COVID-19 pandemic, the importance of vaccinating children against SARS-CoV-2 was rapidly established. This study describes the safety of CoronaVac® in children and adolescents between 3- and 17-years-old in a multicenter study in Chile with two vaccine doses in a 4-week interval. For all participants, immediate adverse events (AEs), serious AEs (SAEs), and AEs of special interest (AESIs) were registered throughout the study. In the safety subgroup, AEs were recorded 28 days after each dose. COVID-19 surveillance was performed throughout the study. A total of 1139 individuals received the first and 1102 the second dose of CoronaVac®; 835 were in the safety subgroup. The first dose showed the highest number of AEs: up to 22.2% of participants reported any local and 17.1% systemic AE. AEs were more frequent in adolescents after the first dose, were transient, and mainly mild. Pain at the inoculation site was the most frequent AE for all ages. Fever was the most frequent systemic AE for 3–5 years old and headache in 6–17 years old. No SAEs or AESIs related to vaccination occurred. Most of the COVID-19 cases were mild and managed as outpatients. CoronaVac® was safe and well tolerated in children and adolescents, with different safety patterns according to age. © 2023 by the authors.
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    Immune responses during COVID-19 breakthrough cases in vaccinated children and adolescents
    (Frontiers Media SA, 2024) Rivera-Pérez, Daniela; Méndez, Constanza; Diethelm-Varela, Benjamín; Melo-González, Felipe; Vázquez, Yaneisi; Meng, Xing; Xin, Qianqian; Fasce, Rodrigo A.; Fernández, Jorge; Mora, Judith; Ramirez, Eugenio; Acevedo, Mónica L.; Valiente-Echeverría, Fernando; Soto-Rifo, Ricardo; Grifoni, Alba; Weiskopf, Daniela; Sette, Alessandro; Astudillo, Patricio; Le Corre, Nicole; Abarca, Katia; Perret, Cecilia; González, Pablo A.; Soto, Jorge A.; Bueno, Susan M.; 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.
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    Inactivated Vaccine-Induced SARS-CoV-2 Variant-Specific Immunity in Children
    (American Society for Microbiology, 2022-12) Soto, Jorge A.; Melo González, Felipe; Gutierrez Vera, Cristián; Schultz, Bárbara M.; Berríos Rojas, Roslye V.; Rivera Pérez, Daniela; Piña Iturbe, Alejandro; Hoppe Elsholz, Guillermo; Duarte, Luisa F.; Vázquez, Yaneisi; Moreno Tapia, Daniela; Ríos, Mariana; Palacios, Pablo A.; Garcia Betancourt, Richard; Santibañez, Álvaro; Pacheco, Gaspar A.; Mendez, Constanza; Andrade, Catalina A.; Silva, Pedro H.; Diethelm Varela, Benjamín; Astudillo, Patricio; Calvo, Mario; Cárdenas, Antonio; González, Marcela; Goldsack, Macarena; Gutiérrez, Valentina; Potin, Marcela; Schilling, Andrea; Tapia, Lorena I.; Twele, Loreto; Villena, Rodolfo; Grifoni, Albar; Sette, Alessandro; Weiskopf, Daniela; Fasce, Rodrigo A.; Fernández, Jorge; Mora, Judith; Ramírez, Eugenio; Gaete Argel, Aracelly; Acevedo, Mónica L.; Valiente Echeverría, Fernando; Soto Rifo, Ricardo; Retamal Díaz, Angello; Muñoz Jofré, Nathalia; Meng, Xing; Xin, Qianqian; Alarcón Bustamante, Eduardo; González Aramundiz, José V.; Le Corre, Nicole; Álvarez Figueroa, María Javiera; González, Pablo A.; Abarca, Katia; Perret, Cecilia; Carreño, Leandro J.; Bueno, Susan M.; Kalergis, Alexis 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 CD41 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 CD41 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 CD41 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 CD41 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. Copyright © 2022 Soto et al.