Browsing by Author "Perret, C."
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- ItemAn inactivated SARS-CoV-2 vaccine is safe and induces humoral and cellular immunity against virus variants in healthy children and adolescents in Chile(2022) Soto, J.A.; Melo-González, F.; Gutierrez-Vera, C.; Schultz, B.M.; Berríos-Rojas, R.V.; Rivera-Pérez, D.; Piña-Iturbe, A.; Hoppe-Elsholz, G.; Duarte, L.F.; Vázquez, Y.; Moreno-Tapia, D.; Ríos, M.; Palacios, P.A.; Garcia-Betancourt, R.; Santibañez, Á.; Mendez, C.; Diethelm-Varela, B.; Astudillo, P.; Calvo, M.; Cárdenas, A.; González, M.; Goldsack, M.; Gutiérrez, V.; Potin, M.; Schilling, A.; Tapia, L.I.; Twele, L.; Villena, R.; Grifoni, A.; Sette, A.; Weiskopf, D.; Fasce, R.A.; Fernández, J.; Mora, J.; Ramírez, E.; Gaete-Argel, A.; Acevedo, M.; Valiente-Echeverría, F.; Soto-Rifo, R.; Retamal-Díaz, A.; Muñoz-Jofré, N.; Meng, X.; Xin, Q.; Alarcón-Bustamante, E.; González-Aramundiz, J.V.; Le Corre, N.; Álvarez, M.J.; González, P.A.; Abarca, K.; Perret, C.; Carreño, L.J.; Kalergis, A.M.; Bueno, S.M.
- ItemBrotes de salmonelosis y el tamaño y rol del Estado en Chile(2012) Fica, A.; Acosta, G.; Dabanch, J.; Perret, C.; Torres, M.; López, J.; Jofré, L.; Weitzel, T.Durante el año 2011 dos brotes de infecciones por Salmonella afectaron la Región Metropolitana (RM) de Chile: uno de fiebre tifoidea y otro de gastroenteritis por Salmonella serotipo Enteritidis, infecciones que habían declinado en los últimos años. Se analizan las probables causas de esta reemergencia. Para el desarrollo de este trabajo se consultaron sitios web gubernamentales y de las Naciones Unidas. Las tasas de fiebre tifoidea han declinado progresivamente hasta tasas muy bajas siendo la actual cercana a un caso por 100.000 habitantes, disminución asociada a las mejorías en las condiciones de vida de la población que se expresa por el índice de desarrollo humano alcanzado. El brote del año 2011 estuvo asociado a un clon predominante que afectó al sector occidente de la RM y donde el único factor de riesgo involucrado fue el consumo de verduras adquiridas en distintas ferias libres del mismo sector, sin lograr la identificación del sitio de origen. Aunque la notificación de esta enfermedad se ha optimizado en los últimos años, al igual que la capacidad de tipificación molecular por parte del Laboratorio de Referencia (ISP), este brote se produce en forma coincidente con un bajo número de fiscalizaciones alimentarias en la RM (la más baja de Chile), explicado probablemente por el bajo número de personal en la repartición responsable en relación al tamaño de la población. En el caso de las infecciones por Salmonella serotipo Enteritidis, la tasa actual es el doble de la observada hace una década (10,7 vs 5,3 casos por 100.000 habitantes) con un incremento progresivo de los brotes alimentarios ligados a este microorganismo desde el 2005 (7 a 31 brotes anuales). La persistencia de este problema está asociada a una escasa actividad fiscalizadora del Estado de Chile hacia los planteles avícolas, a la ausencia de una cadena de frío en la distribución y venta de huevos, y a la falta de educación sobre este tema en la población. La reciente normativa de prohibir la venta de mayonesa elaborada artesanalmente, es un paso importante cuyo impacto aún debe ser evaluado. Conclusiones: La persistencia y reemergencia de ambas salmonelosis en Chile sugiere la existencia de problemas crónicos sobre el tamaño y capacidad del Estado en la seguridad alimentaria del país.
- ItemEvaluation of ELISA-based multiplex peptides for the detection of human serum antibodies induced by zika virus infection across various countries(2021) Viedma, M.D.P.M.; Panossian, S.; Gifford, K.; García, K.; Figueroa, I.; Parham, L.; de Moraes, L.; Gomes, L.N.; García-Salum, T.; Perret, C.; Weiskopf, D.; Tan, G.S.; Silva, A.A.; Boaventura, V.; Ruiz-Palacios, G.M.; Sette, A.; De Silva, A.D.; Medina, R.A.; Lorenzana, I.; Akrami, K.M.; Khouri, R.; Olson, D.; Pickett, B.E.Zika virus (ZIKV) is a mosquito-borne Flavivirus with a positive-sense RNA genome, which are generally transmitted through the bite of an infected Aedes mosquito. ZIKV infections could be associated with neurological sequelae that, and otherwise produces similar clinical symptoms as other co-circulating pathogens. Past infection with one member of the Flavivirus genus often induces cross-reactive antibodies against other flaviruses. These attributes complicate the ability to differentially diagnose ZIKV infection from other endemic mosquito-borne viruses, making it both a public health issue as well as a diagnostic challenge. We report the results from serological analyses using arbovirus-specific peptides on 339 samples that were previously collected from 6 countries. Overall, we found that our multiplexed peptide-based ELISA was highly efficient for identifying ZIKV antibodies as early as 2 weeks post infection, and that it correlates with microneutralization, plaque reduction neutralization tests (PRNTs) and commercial tests for ZIKV in previously characterized samples. We observed that seropositivity varied by patient cohort, reflecting the sampling period in relation to the 2015–2016 ZIKV outbreak. This work evaluates the accuracy, specificity, and sensitivity of our peptide-based ELISA method for detecting ZIKV antibodies from geographically diverse regions. These findings can contribute to ongoing serological methods development and can be adapted for use in future studies.
- ItemInactivated Vaccine-Induced SARS-CoV-2 Variant-Specific Immunity in Children(2022) Soto, J.A.; Melo-González, F.; Gutierrez-Vera, C.; Schultz, B.M.; Berríos-Rojas, R.V.; Rivera-Pérez, D.; Piña-Iturbe, A.; Hoppe-Elsholz, G.; Duarte, L.F.; Vázquez, Y.; Moreno-Tapia, D.; Ríos, M.; Palacios, P.A.; Garcia-Betancourt, R.; Santibañez, Á.; Pacheco, G.A.; Mendez, C.; Andrade, C.A.; Silva, P.H.; Diethelm-Varela, B.; Astudillo, P.; Calvo, M.; Cárdenas, A.; González, M.; Goldsack, M.; Gutiérrez, V.; Potin, M.; Schilling, A.; Tapia, L.I.; Twele, L.; Villena, R.; Grifoni, A.; Sette, A.; Weiskopf, D.; Fasce, R.A.; Fernández, J.; Mora, J.; Ramírez, E.; Gaete-Argel, A.; Acevedo, M.L.; Valiente-Echeverría, F.; Soto-Rifo, R.; Retamal-Díaz, A.; Muñoz-Jofré, N.; Meng, X.; Xin, Q.; Alarcón-Bustamante, E.; González-Aramundiz, J.V.; Le Corre, N.; Álvarez-Figueroa, M.J.; González, P.A.; Abarca, K.; Perret, C.; Carreño, L.J.; Bueno, S.M.; Kalergis, A.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 CD4+ 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 CD4+ 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 CD4+ 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 CD4+ 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.
- ItemNon-typable Haemophilus influenzae severe pneumonia in an infant: case report,Neumonía grave causada por Haemophilus influenzae no tipificable en un lactante: reporte de un caso.(2005) Vega-Briceño, L.E.; Perret, C.; Holmgren, N.; Sánchez, I.Haemophilus influenzae b (Hib) disease used to be a frequent cause of pneumonia in children. After the widespread use of Hib conjugate vaccines, non-b H. influenzae have become an important cause of pneumonia. We present the case of an infant with severe pneumonia with empyema and bacteremia after he had completed the Hib vaccination schedule. Non typable H. influenzae was recovered from blood and pleural effusion cultures. We review the literature about this unusual clinical presentation in our community and alert about the possible emergence of non typable H. influenzae as a frequent cause of community-acquired pneumonia in children.
- ItemYellow fever vaccination for chilean tourists visiting Brazil. Practical considerations(2018) Weitzel, T.; Perret, C.; Valdivieso, F.; Abarca, K.; Vial, P.Due to the recent yellow fever outbreak affecting the costal region of Brazil, including main touristic destinations, there is a high demand of yellow fever vaccination. This publication addresses the most relevant practical issues regarding this vaccine for tourists visiting Brazil and aims to serve as a guideline for non-expert physicians in Chile and elsewhere.