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Araos Bralic, Rafael Ignacio

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Araos Bralic

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Rafael Ignacio

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  • Publication
    Effectiveness of an inactivated SARS-CoV-2 vaccine in children and adolescents: a large-scale observational study
    (2023) Jara, Alejandro; Undurraga, Eduardo; Flores, Juan; Zubizarreta, José; González, Cecilia; Pizarro, Alejandra; Ortuño, Duniel; Acevedo, Johanna; Leo, Katherinne; Paredes, Fabio; Bralic , Tomás; Vergara, Verónica; Leon, Francisco; Parot, Ignacio; Leighton, Paulina; Suárez, Pamela; Rios, Juan; García, Heriberto; Rafael Araos; Araos Bralic, Rafael Ignacio
    Background: Policymakers urgently need evidence to adequately balance the costs and benefits of mass vaccination against COVID-19 across all age groups, including children and adolescents. In this study, we aim to assess the effectiveness of CoronaVac's primary series among children and adolescents in Chile. Methods: We used a large prospective national cohort of about two million children and adolescents 6-16 years to estimate the effectiveness of an inactivated SARS-CoV-2 vaccine (CoronaVac) in preventing laboratory-confirmed symptomatic SARS-CoV-2 infection (COVID-19), hospitalisation, and admission to an intensive care unit (ICU) associated with COVID-19. We compared the risk of individuals treated with a complete primary immunization schedule (two doses, 28 days apart) with the risk of unvaccinated individuals during the follow-up period. The study was conducted in Chile from June 27, 2021, to January 12, 2022, when the SARS-CoV-2 Delta variant was predominant but other variants of concern were co-circulating, including Omicron. We used inverse probability-weighted survival regression models to estimate hazard ratios of complete immunization over the unvaccinated status, accounting for time-varying vaccination exposure and adjusting for relevant demographic, socioeconomic, and clinical confounders. Findings: The estimated adjusted vaccine effectiveness for the inactivated SARS-CoV-2 vaccine in children aged 6-16 years was 74.5% (95% CI, 73.8-75.2), 91.0% (95% CI, 87.8-93.4), 93.8% (95% CI, 87.8-93.4) for the prevention of COVID-19, hospitalisation, and ICU admission, respectively. For the subgroup of children 6-11 years, the vaccine effectiveness was 75.8% (95% CI, 74.7-76.8) for the prevention of COVID-19 and 77.9% (95% CI, 61.5-87.3) for the prevention of hospitalisation. Interpretation: Our results suggest that a complete primary immunization schedule with the inactivated SARS-CoV-2 vaccine provides effective protection against severe COVID-19 disease for children 6-16 years. Funding: Agencia Nacional de Investigación y Desarrollo (ANID) Millennium Science Initiative Program and Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias (FONDAP)
  • Publication
    Antibiotic Consumption During the Coronavirus Disease 2019 Pandemic and Emergence of Carbapenemase-Producing Klebsiella pneumoniae Lineages Among Inpatients in a Chilean Hospital: A Time-Series Study and Phylogenomic Analysis
    (2023) Allel, Kasim; Peters, Anne Sophie; Conejeros, José; Martínez, José; Spencer, Maria; Riquelme, Roberto; Rivas Jiménez, Lina María; Rojas, Pamela; Orellana, Cristian; García, Patricia; Araos Bralic, Rafael Ignacio; McGovern, Olivia; Patel, Twisha; Arias, Cesar; Lessa, Fernanda; Undurraga, Eduardo; Munita, Jose M.
    Background: The impact of coronavirus disease 2019 (COVID-19) on antimicrobial use (AU) and resistance has not been well evaluated in South America. These data are critical to inform national policies and clinical care. Methods: At a tertiary hospital in Santiago, Chile, between 2018 and 2022, subdivided into pre- (3/2018-2/2020) and post-COVID-19 onset (3/2020-2/2022), we evaluated intravenous AU and frequency of carbapenem-resistant Enterobacterales (CRE). We grouped monthly AU (defined daily doses [DDD]/1000 patient-days) into broad-spectrum β-lactams, carbapenems, and colistin and used interrupted time-series analysis to compare AU during pre- and post-pandemic onset. We studied the frequency of carbapenemase-producing (CP) CRE and performed whole-genome sequencing analyses of all carbapenem-resistant (CR) Klebsiella pneumoniae (CRKpn) isolates collected during the study period. Results: Compared with pre-pandemic, AU (DDD/1000 patient-days) significantly increased after the pandemic onset, from 78.1 to 142.5 (P < .001), 50.9 to 110.1 (P < .001), and 4.1 to 13.3 (P < .001) for broad-spectrum β-lactams, carbapenems, and colistin, respectively. The frequency of CP-CRE increased from 12.8% pre-COVID-19 to 51.9% after pandemic onset (P < .001). The most frequent CRE species in both periods was CRKpn (79.5% and 76.5%, respectively). The expansion of CP-CRE harboring blaNDM was particularly noticeable, increasing from 40% (n = 4/10) before to 73.6% (n = 39/53) after pandemic onset (P < .001). Our phylogenomic analyses revealed the emergence of two distinct genomic lineages of CP-CRKpn: ST45, harboring blaNDM, and ST1161, which carried blaKPC. Conclusions: AU and the frequency of CP-CRE increased after COVID-19 onset. The increase in CP-CRKpn was driven by the emergence of novel genomic lineages. Our observations highlight the need to strengthen infection prevention and control and antimicrobial stewardship efforts.
  • Publication
    Navigating economic turmoil: Chilean businesses during COVID-19 lockdowns and vaccine rollouts
    (2024) Pertuze, Julio A.; Montégu, José Pablo; González, Cecilia; Araos Bralic, Rafael Ignacio; Daza, Paula
    Objectives: This study evaluates the effects of COVID-19 lockdowns, differentiated by their stringency, on the sales of Chilean businesses across various size categories and industries throughout 2020 and 2021. It also explores the role of the vaccination campaign and the implementation of the Mobility Pass in mitigating the negative economic effects of stringent containment measures. Methods: The study uses administrative data from the Chilean Internal Revenue Service (SII), examining sales across different business sizes and industries, from March 2020 to December 2021. Through an econometric analysis, we estimate the effects of lockdowns on business sales during two distinct periods: initial reliance on dynamic non-pharmaceutical interventions (NPIs) pre-vaccine, and a subsequent stage characterized by high vaccine uptake and reduced NPI stringency. Results: Lockdowns significantly reduced sales across all business sizes and most industries during the first period, with microenterprises and certain service sectors experiencing the highest decline. The national vaccination campaign and the introduction of the Mobility Pass in the second period appears to have mitigated the negative effects of lockdowns, primarily benefiting micro and small firms. Conclusions: The study highlights the trade-offs between health and economic outcomes during the pandemic, stressing the importance to alleviate mobility restrictions post-vaccine rollout to ease the economic strain on businesses. The findings call for targeted support measures for MSMEs and vulnerable industries affected by NPIs.
  • Publication
    Effectiveness of the second COVID-19 booster against Omicron: a large-scale cohort study in Chile
    (2023) Jara, Alejandro; Cuadrado, Cristobal; Undurraga, Eduardo; García , Christian; Nájera, Manuel; Bertoglia, María; Vergara, Verónica; Fernández , Jorge; García, Heriberto; Araos Bralic, Rafael Ignacio
    In light of the ongoing COVID-19 pandemic and the emergence of new SARS-CoV-2 variants, understanding the effectiveness of various booster vaccination regimens is pivotal. In Chile, using a prospective national cohort of 3.75 million individuals aged 20 or older, we evaluate the effectiveness against COVID-19-related intensive care unit (ICU) admissions and death of mRNA-based second vaccine boosters for four different three-dose background regimes: BNT162b2 primary series followed by a homologous booster, and CoronaVac primary series followed by an mRNA booster, a homologous booster, and a ChAdOx-1 booster. We estimate the vaccine effectiveness weekly from February 14 to August 15, 2022, by determining hazard ratios of immunization over non-vaccination, accounting for relevant confounders. The overall adjusted effectiveness of a second mRNA booster shot is 88.2% (95%CI, 86.2-89.9) against ICU admissions and 90.5% (95%CI 89.4-91.4) against death. Vaccine effectiveness shows a mild decrease for all regimens and outcomes, probably linked to the introduction of BA.4 and BA.5 Omicron sub-lineages and the waning of immunity. Based on our findings, individuals might not need additional boosters for at least 6 months after receiving a second mRNA booster shot in this setting. A la luz de la actual pandemia de COVID-19 y la aparición de nuevas variantes del SARS-CoV-2, es fundamental comprender la eficacia de varios regímenes de vacunación de refuerzo. En Chile, utilizando una cohorte nacional prospectiva de 3,75 millones de personas de 20 años o más, evaluamos la efectividad contra las admisiones a unidades de cuidados intensivos (UCI) relacionadas con COVID-19 y la muerte de segundas dosis de refuerzo basadas en ARNm para cuatro dosis diferentes de tres dosis. regímenes: serie primaria BNT162b2 seguida de un refuerzo homólogo, y serie primaria CoronaVac seguida de un refuerzo de ARNm, un refuerzo homólogo y un refuerzo de ChAdOx-1. Estimamos la efectividad de la vacuna semanalmente del 14 de febrero al 15 de agosto de 2022, determinando los índices de riesgo de inmunización frente a no vacunación, teniendo en cuenta los factores de confusión relevantes. La eficacia global ajustada de una segunda inyección de refuerzo de ARNm es del 88,2% (IC del 95%, 86,2-89,9) frente a los ingresos en la UCI y del 90,5% (IC del 95%, 89,4-91,4) frente a la muerte. La eficacia de la vacuna muestra una leve disminución en todos los regímenes y resultados, probablemente relacionada con la introducción de los sublinajes Omicron BA.4 y BA.5 y la disminución de la inmunidad. Según nuestros hallazgos, es posible que las personas no necesiten refuerzos adicionales durante al menos 6 meses después de recibir una segunda inyección de refuerzo de ARNm en este entorno.