Browsing by Author "Rojas, Alvaro"

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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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    Pseudomonas aeruginosa Community-Onset Bloodstream Infections: Characterization, Diagnostic Predictors, and Predictive Score Development-Results from the PRO-BAC Cohort
    (2022) Martinez Perez-Crespo, Pedro Maria; Rojas, Alvaro; Felipe Lanz-Garcia, Joaquin; Retamar-Gentil, Pilar; Maria Reguera-Iglesias, Jose; Lima-Rodriguez, Olalla; del Arco Jimenez, Alfonso; Fernandez Suarez, Jonathan; Jover-Saenz, Alfredo; Goikoetxea Aguirre, Josune; Leon Jimenez, Eva; Luisa Canton-Bulnes, Maria; Ortega Lafont, Pilar; Arminanzas Castillo, Carlos; Blanco, Juan Sevilla; Cuquet Pedragosa, Jordi; Boix-Palop, Lucia; Becerril Carral, Berta; Bahamonde-Carrasco, Alberto; Marrodan Ciordia, Teresa; Natera Kindelan, Clara; Reche Molina, Isabel Maria; Herrero Rodriguez, Carmen; Perez Camacho, Ines; Vinuesa Garcia, David; Galan-Sanchez, Fatima; Smithson Amat, Alejandro; Merino de Lucas, Esperanza; Sanchez-Porto, Antonio; Guzman Garcia, Marcos; Lopez-Hernandez, Inmaculada; Rodriguez-Bano, Jesus; Eduardo Lopez-Cortes, Luis
    Community-onset bloodstream infections (CO-BSI) caused by gram-negative bacilli are common and associated with significant mortality; those caused by Pseudomonas aeruginosa are associated with worse prognosis and higher rates of inadequateempirical antibiotic treatment. The aims of this study were to describe the characteristics of patients with CO-BSI caused by P. aeruginosa, to identify predictors, and to develop a predictive score for P. aeruginosa CO-BSI. Materials/methods: PROBAC is a prospective cohort including patients >14 years with BSI from 26 Spanish hospitals between October 2016 and May 2017. Patients with monomicrobial P. aeruginosa CO-BSI and monomicrobial Enterobacterales CO-BSI were included. Variables of interest were collected. Independent predictors of Pseudomonas aeruginosa CO-BSI were identified by logistic regression and a prediction score was developed. Results: A total of 78patients with P. aeruginosa CO-BSI and 2572 with Enterobacterales CO-BSI were included. Patients with P. aeruginosa had a median age of 70 years (IQR 60-79), 68.8% were male, median Charlson score was 5 (IQR 3-7), and 30-daymortality was 18.5%. Multivariate analysis identified the following predictors of CO-BSI-PA [adjusted OR (95% CI)]: male gender [1.89 (1.14-3.12)], haematological malignancy [2.45 (1.20-4.99)], obstructive uropathy [2.86 (1.13-3.02)], source of infection other than urinary tract, biliary tract or intra-abdominal [6.69 (4.10-10.92)] and healthcare-associated BSI [1.85 (1.13-3.02)]. Anindex predictive of CO-BSI-PA was developed; scores >= 3.5 showed a negative predictive value of 89% and an area under the receiver operator curve (ROC) of 0.66. Conclusions: We did not find a good predictive score of P. aeruginosa CO-BSI due to its relatively low incidence in the overall population. Our model includes variables that are easy to collect in real clinical practice and could be useful to detect patients with very low risk of P. aeruginosa CO-BSI.
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    Incidencia de bacterias multi-resistentes en unidades de cuidados intensivos de hospitales chilenos
    (2017) Paz Acuna, M.; Cifuentes, Marcela; Silva, Francisco; Rojas, Alvaro; Cerda, Jaime; Labarca, Jaime; Grp Colaborativo Resistencia
    Introduction: Incidence of multi-resistant bacteria is an indicator that permits better estimation of the magnitude of bacterial resistance in hospitals. Aim: To evaluate the incidence of relevant multi-drug resistant bacteria in intensive care units (ICUs) of Chile. Methods: Participating hospitals submitted information about the number of isolates from infected or colonized patients with 7 epidemiologically relevant multi-resistant bacteria in adult and pediatric ICUs between January 1, 2014 and October 31, 2015 and the number of bed days occupied in these units in the same period was requested. With these data incidence was calculated per 1,000 patient days for each unit. Results: Information from 20 adults and 9 pediatric ICUs was reviewed. In adult ICUs the bacteria with the highest incidence were K. pneumoniae ESBL [4.72 x 1,000 patient day (1.21-13.89)] and oxacillin-resistant S. aureus [3.85 (0.71-12.66)]. In the pediatric units the incidence was lower, highlighting K. pneumoniae ESBL [2.71 (0-7.11)] and carbapenem-resistant P aeruginosa [1.61 (0.31-9.25)]. Conclusion: Important differences between hospitals in the incidence of these bacteria were observed. Incidence of multi-resistant bacteria in adult ICU was significantly higher than in pediatric ICU for most of the studied bacterias.
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    Multiple Mycotic Aneurysms Due to Penicillin Nonsusceptible Streptococcus pneumoniae Solved With Endovascular Repair
    (ELSEVIER SCIENCE INC, 2010) Rojas, Alvaro; Mertens, Renato; Arbulo, Douglas; Garcia, Patricia; Labarca, Jaime
    Mycotic aneurysm is a life-threatening condition. We report the case of an 83-year-old white female who had pneumonia, and 3 months later she was admitted with multiple sacular mycotic aneurysms due to penicillin nonsusceptible Streptococcus pneumoniae. Successful combination therapy with antibiotics and endovascular repair was done.
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    Safety and Non-Inferiority Evaluation of Two Immunization Schedules with an Inactivated SARS-CoV-2 Vaccine in Adults: A Randomized Clinical Trial
    Abarca Villaseca, Katia; Iturriaga Ortiz, Carolina Alejandra; Urzua, Marcela; Le Corre Perez, Monique Nicole; Pineda Núñez, Augusto Naim; Fernandez Anwandter, Carolina; Domínguez De Landa, María Angelica; González Carbonell, Pablo Andrés; Bueno, Susan M.; Donato, Paulina; Espinoza, Pilar; Fuentes, Daniela; Gonzalez, Marcela; Guzman, Paula; Munoz-Venturelli, Paula; Perez, Carlos M.; Potin, Marcela; Rojas, Alvaro; Gonzalez-Aramundiz, Jose, V; Galvez, Nicolas M. S.; Aguirre-Boza, Francisca; Aljaro, Sofia; Federico Batiz, Luis; Campisto, Yessica; Cepeda, Mariela; Cortes, Aaron; Lopez, Sofia; Loreto Perez, Maria; Schilling, Andrea; Kalergis, Alexis M.
    Several vaccines have been developed to control the COVID-19 pandemic. CoronaVac (R), an inactivated SARS-CoV-2 vaccine, has demonstrated safety and immunogenicity, preventing severe COVID-19 cases. We investigate the safety and non-inferiority of two immunization schedules of CoronaVac (R) in a non-inferiority trial in healthy adults. A total of 2302 healthy adults were enrolled at 8 centers in Chile and randomly assigned to two vaccination schedules, receiving two doses with either 14 or 28 days between each. The primary safety and efficacy endpoints were solicited adverse events (AEs) within 7 days of each dose, and comparing the number of cases of SARS-CoV-2 infection 14 days after the second dose between the schedules, respectively. The most frequent local AE was pain at the injection site, which was less frequent in participants aged >= 60 years. Other local AEs were reported in less than 5% of participants. The most frequent systemic AEs were headache, fatigue, and myalgia. Most AEs were mild and transient. There were no significant differences for local and systemic AEs between schedules. A total of 58 COVID-19 cases were confirmed, and all but 2 of them were mild. No differences were observed in the proportion of COVID-19 cases between schedules. CoronaVac (R) is safe, especially in >= 60-year-old participants. Both schedules protected against COVID-19 hospitalization.