Browsing by Author "Soto-Rifo, Ricardo"
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Publication Neutralizing antibodies induced by homologous and heterologous boosters in CoronaVac vaccines in Chile(2023) Acevedo, Johanna; Acevedo, Mónica L.; Gaete-Argel, Aracelly; Araos, Rafael; González, Cecilia; Espinoza, Daniela; Rivas, Solange; Pizarro, Pablo; Jarpa, Stephan; Soto-Rifo, Ricardo; Jara, Alejandro; Valiente-Echeverría, FernandoObjectives: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. Methods:Individuals previously inoculated with 2 doses of CoronaVac (N = 523) were recruited in the context of the REFUERZO clinical trial (NCT04992182) and received either placebo (N = 129), or a booster dose of CoronaVac (N = 134), BNT162b2 (N = 133), or ChAdOx1 (N = 127). Pseudovirus neutralizing antibody titres (pVNT) were determined at baseline (day 0) as well as at days 14, 30, 60, and 90 after booster dose administration. Results:Inoculating a booster dose increases the pVNTs titres at days 14 and 30 in all groups, (13.5- and 12.0-fold increase for the CoronaVac group; 247.0- and 212.3-fold increase for the BTN162b2 group; and 89.1- and 128.1-fold increase for ChAdOx1 at each time point, respectively) with a decline observed at days 60 and 90. However, although pVNTs remained significantly higher for the BTN162b2 and ChAdOx1 groups at days 60 and 90, NAb titres reached baseline levels in the CoronaVac group at 90 days after inoculation. Discussion: A single heterologous booster (BTN162b2 or ChAdOx1) in individuals who completed the CoronaVac primary series resulted in an important increase in NAb titres remaining significantly higher at least for 90 days. These data may directly impact middle- and low-income countries currently using CoronaVac as the main vaccination strategy.Item Safety and Immunogenicity of an Inactivated Severe Acute Respiratory Syndrome Coronavirus 2 Vaccine in a Subgroup of Healthy Adults in Chile(2021) Bueno, Susan M.; Abarca, Katia; González, Pablo A.; Gálvez, Nicolás M. S.; Soto, Jorge A.; Duarte, Luisa F.; Schultz, Bárbara M.; Pacheco, Gaspar A.; González, Liliana A.; Vázquez, Yaneisi; Ríos, Mariana; Melo-González, Felipe; Rivera-Pérez, Daniela; Iturriaga, Carolina; Urzúa, Marcela; Domínguez, Angélica; Andrade, Catalina A.; Berríos-Rojas, Roslye V.; Canedo-Marroquín, Gisela; Covián, Camila; Moreno-Tapia, Daniela; Saavedra, Farides; Vallejos, Omar P.; Donato, Paulina; Espinoza, Pilar; Fuentes, Daniela; González, Marcela; Guzmán, Paula; Muñoz Venturelli, Paula; Pérez, Carlos M.; Potin, Marcela; Rojas, Álvaro; Fasce, Rodrigo A.; Fernández, Jorge; Mora, Judith; Ramírez, Eugenio; Gaete-Argel, Aracely; Oyarzún-Arrau, Aarón; Soto-Rifo, Ricardo; Weiskopf, Daniela; Sette, Alessandro; Zeng, Gang; Meng, Weining; González-Aramundiz, José V.; Kalergis, Alexis M.; CoronaVac03CL Study GroupBackground. The development of effective vaccines against coronavirus disease 2019 is a global priority. CoronaVac is an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine with promising safety and immunogenicity profiles. This article reports safety and immunogenicity results obtained for healthy Chilean adults aged ≥18 years in a phase 3 clinical trial. Methods. Volunteers randomly received 2 doses of CoronaVac or placebo, separated by 2 weeks. A total of 434 volunteers were enrolled, 397 aged 18–59 years and 37 aged ≥60 years. Solicited and unsolicited adverse reactions were registered from all volun- teers. Blood samples were obtained from a subset of volunteers and analyzed for humoral and cellular measures of immunogenicity. Results. The primary adverse reaction in the 434 volunteers was pain at the injection site, with a higher incidence in the vaccine than in the placebo arm. Adverse reactions observed were mostly mild and local. No severe adverse events were reported. The humoral evaluation was performed on 81 volunteers. Seroconversion rates for specific anti-S1-receptor binding domain (RBD) immunoglobulin G (IgG) were 82.22% and 84.44% in the 18–59 year age group and 62.69% and 70.37% in the ≥60 year age group, 2 and 4 weeks after the second dose, respectively. A significant increase in circulating neutralizing antibodies was detected 2 and 4 weeks after the second dose. The cellular evaluation was performed on 47 volunteers. We detected a significant induction of T-cell responses characterized by the secretion of interferon-γ (IFN-γ) upon stimulation with Mega Pools of peptides from SARS-CoV-2. Conclusions. Immunization with CoronaVac in a 0–14 schedule in Chilean adults aged ≥18 years is safe, induces anti-S1-RBD IgG with neutralizing capacity, activates T cells, and promotes the secretion of IFN-γ upon stimulation with SARS-CoV-2 antigens.Publication Serological study of CoronaVac vaccine and booster doses in Chile: immunogenicity and persistence of anti-SARS-CoV-2 spike antibodies(2022) Vargas, Leonardo; Valdivieso, Nicolás; Tempio, Fabián; Simon, Valeska; Sauma, Daniela; Valenzuela, Lucía; Beltrán, Caroll; Castillo- Delgado, Loriana; Contreras-Benavides, Ximena; Acevedo, Mónica L.; Acevedo, Johanna; Gonzalez, Rafael I.; Valiente-Echeverría, Fernando; Soto-Rifo, Ricardo; Rosemblatt, Mario; López, Mercedes; Osorio, Fabiola; Bono, María RosaBackground: Chile was severely affected by COVID19 outbreaks but was also one of the first countries to start a nationwide program to vaccinate against the disease. Furthermore, Chile became one of the fastest countries to inoculate a high percentage of the target population and implemented homologous and heterologous booster schemes in late 2021 to prevent potential immunological waning. The aim of this study is to compare the immunogenicity and time course of the humoral response elicited by the CoronaVac vaccine in combination with homologous versus heterologous boosters. Methods: We compared the immunogenicity of two doses of CoronaVac and BNT162b2 vaccines and one homologous or heterologous booster through an ELISA assay directed against the ancestral spike protein of SARS-CoV-2. Sera were collected from individuals during the vaccination schedule and throughout the implementation of homologous and heterologous booster programs in Chile. Results: Our findings demonstrate that a two-dose vaccination scheme with CoronaVac induces lower levels of anti-SARS-CoV-2 spike antibodies than BNT162b2 in a broad age range (median age 42 years; interquartile range (IQR) 27-61). Furthermore, antibody production declines with time in individuals vaccinated with CoronaVac and less noticeably, with BNT162b2. Analysis of booster schemes revealed that individuals vaccinated with two doses of CoronaVac generate immunological memory against the SARS-CoV-2 ancestral strain, which can be re-activated with homologous or heterologous (BNT162b2 and ChAdOx1) boosters. Nevertheless, the magnitude of the antibody response with the heterologous booster regime was considerably higher (induction fold BNT162b2: 11.2x; ChAdoX1; 12.4x; CoronaVac: 6.0x) than the responses induced by the homologous scheme. Both homologous and heterologous boosters induced persistent humoral responses (median 122 days, IQR (108-133)), although heterologous boosters remained superior in activating a humoral response after 100 days. Conclusions: Two doses of CoronaVac induces antibody titers against the SARS-CoV-2 ancestral strain which are lower in magnitude than those induced by the BNT162b2 vaccine. However, the response induced by CoronaVac can be greatly potentiated with a heterologous booster scheme with BNT162b2 or ChAdOx1 vaccines. Furthermore, the heterologous and homologous booster regimes induce a durable antibody response which does not show signs of decay 3 months after the booster dose.