Browsing by Author "González, Cecilia"
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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 IgnacioBackground: 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)Item Effectiveness of an Inactivated SARS-CoV-2 Vaccine in Chile(2021) Jara, Alejandro; Undurraga, Eduardo; González, Cecilia; Paredes, Fabio; Fontecilla, Tomás; Jara, Gonzalo; Pizarro, Alejandra; Acevedo, Johanna; Leo, Katherinne; Leon, Francisco; Sans, Carlos; Leighton, Paulina; Suárez, Pamela; García-Escorza, Heriberto; Araos, Rafael;BACKGROUND Mass vaccination campaigns to prevent coronavirus disease 2019 (Covid-19) are occurring in many countries; estimates of vaccine effectiveness are urgently needed to support decision making. A countrywide mass vaccination campaign with the use of an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (CoronaVac) was conducted in Chile starting on February 2, 2021. METHODS We used a prospective national cohort, including participants 16 years of age or older who were affiliated with the public national health care system, to assess the effectiveness of the inactivated SARS-CoV-2 vaccine with regard to preventing Covid-19 and related hospitalization, admission to the intensive care unit (ICU), and death. We estimated hazard ratios using the extension of the Cox proportional-hazards model, accounting for time-varying vaccination status. We estimated the change in the hazard ratio associated with partial immunization (≥14 days after receipt of the first dose and before receipt of the second dose) and full immunization (≥14 days after receipt of the second dose). Vaccine effectiveness was estimated with adjustment for individual demographic and clinical characteristics. RESULTS The study was conducted from February 2 through May 1, 2021, and the cohort included approximately 10.2 million persons. Among persons who were fully immunized, the adjusted vaccine effectiveness was 65.9% (95% confidence interval [CI], 65.2 to 66.6) for the prevention of Covid-19 and 87.5% (95% CI, 86.7 to 88.2) for the prevention of hospitalization, 90.3% (95% CI, 89.1 to 91.4) for the prevention of ICU admission, and 86.3% (95% CI, 84.5 to 87.9) for the prevention of Covid-19–related death.Publication Effectiveness of CoronaVac in children 3–5 years of age during the SARS-CoV-2 Omicron outbreak in Chile(2022) Jara, Alejandro; Undurraga, Eduardo A.; Zubizarreta, José R.; González, Cecilia; Acevedo, Johanna; Pizarro, Alejandra; Vergara, Verónica; Soto-Marchant, Mario; Gilabert, Rosario; Flores, Juan Carlos; Suárez, Pamela; Leighton, Paulina; Eguiguren, Pablo; Ríos, Juan Carlos; Fernández, Jorge; García-Escorza, Heriberto; Araos, RafaelThe outbreak of the B.1.1.529 lineage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (Omicron) has caused an unprecedented number of Coronavirus Disease 2019 (COVID-19) cases, including pediatric hospital admissions. Policymakers urgently need evidence of vaccine effectiveness in children to balance the costs and benefits of vaccination campaigns, but, to date, the evidence is sparse. Leveraging a population-based cohort in Chile of 490,694 children aged 3–5 years, we estimated the effectiveness of administering a two-dose schedule, 28 days apart, of Sinovac’s inactivated SARS-CoV-2 vaccine (CoronaVac). We used inverse probability-weighted survival regression models to estimate hazard ratios of symptomatic COVID-19, hospitalization and admission to an intensive care unit (ICU) for children with complete immunization over non-vaccination, accounting for time-varying vaccination exposure and relevant confounders. The study was conducted between 6 December 2021 and 26 February 2022, during the Omicron outbreak in Chile. The estimated vaccine effectiveness was 38.2% (95% confidence interval (CI), 36.5–39.9) against symptomatic COVID-19, 64.6% (95% CI, 49.6–75.2) against hospitalization and 69.0% (95% CI, 18.6–88.2) against ICU admission. The effectiveness against symptomatic COVID-19 was modest; however, protection against severe disease was high. These results support vaccination of children aged 3–5 years to prevent severe illness and associated complications and highlight the importance of maintaining layered protections against SARS-CoV-2 infection.Publication Effectiveness of homologous and heterologous booster doses for an inactivated SARS-CoV-2 vaccine: a large-scale prospective cohort study(2022) Jara, Alejandro; Undurraga, Eduardo A.; Zubizarreta, José R.; González, Cecilia; Pizarro, Alejandra; Acevedo, Johanna; Leo, Katherinne; Paredes, Favio; Bralic, Tomás; Vergara, Verónica; Mosso, Marcelo; León, Francisco; Parot, Ignacio; Leighton, Paulina; Suárez, Pamela; Ríos, Juan Carlos; García-Escorza, Heriberto; Araos, RafaelBackground: Vaccine protection against Covid-19 may be waning. Several countries have authorized or begun using a booster vaccine dose. Policymakers urgently need evidence of the effectiveness of additional vaccine doses against Covid-19 and its clinical spectrum for individuals with complete primary immunization schedules. Methods: We used a prospective national cohort of 11·2 million persons 16 years or older to assess the effectiveness of CoronaVac, AZD1222, or BNT162b2 vaccine boosters in individuals who completed their primary immunization schedule with CoronaVac compared to unvaccinated individuals. The study was conducted in Chile from February 2 through November 10, 2021. We used inverse probability-weighted survival regression models to estimate hazard ratios, accounting for time-varying vaccination status and adjusting for relevant demographic, socioeconomic, and clinical confounders. We estimated the change in the hazard associated with complete immunization (≥14 days after the booster). Findings: We found an adjusted vaccine effectiveness against symptomatic Covid-19 of 78·8% (95% confidence interval, CI, 76·8–80·6) for a three-dose schedule with CoronaVac, 96·5% (95% CI, 96·2–96·7) for BNT162b2 booster, and 93·2% (95% CI, 92·9–93·6) for the AZD1222 booster. The adjusted vaccine effectiveness against hospitalization, ICU admission, and Covid-19 related deaths was 86·3%, 92·2%, and 86·7% for a three-dose schedule with CoronaVac, 96·1%, 96·2%, and 96·8% for the BNT162b2 booster, and 97·7%, 98·9%, and 98·1% for the AZD1222 booster. Interpretation: Our results suggest that a homologous or heterologous booster shot for individuals with a complete primary vaccination schedule with CoronaVac provides a high level of protection against Covid-19, including severe disease and death. However, heterologous boosters showed higher vaccine effectiveness for all outcomes, providing additional support for using a mix and match approach. Funding Information: Agencia Nacional de Investigación y Desarrollo (ANID) Millennium Science Initiative Program and Fondo de Financiamiento de Centros de Investigación en Áreas Prioritarias (FONDAP). Declaration of Interests: The authors declare no conflicts of interest. Ethics Approval Statement: The research protocol was approved by the Comité Ético Científico Clínica Alemana Universidad del Desarrollo. The study was considered exempt from informed consent, no human health risks were identified. Research analysts belong to the Chilean Ministry of Health; our use of data follows Chilean law 19·628 on personal data protection.Publication Multimodal mechanisms of human sociallyreinforced learning across neurodegenerative diseases(2022) Legaz, Agustina; Abrevaya, Sofía; Dottori, Martín; González, Cecilia; Birba, Agustina; Martorell, Miguel; Aguirre, Julieta; Slachevsky Chonchol, Andrea; Aranguiz, Rafael; Serrano, Cecilia; Gillan, Claire; Leroi, Iracema; García, Adolfo; Fittipaldi, Sol; Ibañez, AgustínSocial feedback can selectively enhance learning in diverse domains. Relevant neurocognitive mechanisms have been studied mainly in healthy persons, yielding correlational findings. Neurodegenerative lesion models, coupled with multimodal brain measures, can complement standard approaches by revealing direct multidimensional correlates of the phenomenon. To this end, we assessed socially reinforced and non-socially reinforced learning in 40 healthy participants as well as persons with behavioural variant frontotemporal dementia (n = 21), Parkinson's disease (n = 31) and Alzheimer's disease (n = 20). These conditions are typified by predominant deficits in social cognition, feedback-based learning and associative learning, respectively, although all three domains may be partly compromised in the other conditions. We combined a validated behavioural task with ongoing EEG signatures of implicit learning (medial frontal negativity) and offline MRI measures (voxel-based morphometry). In healthy participants, learning was facilitated by social feedback relative to non-social feedback. In comparison with controls, this effect was specifically impaired in behavioural variant frontotemporal dementia and Parkinson's disease, while unspecific learning deficits (across social and non-social conditions) were observed in Alzheimer's disease. EEG results showed increased medial frontal negativity in healthy controls during social feedback and learning. Such a modulation was selectively disrupted in behavioural variant frontotemporal dementia. Neuroanatomical results revealed extended temporo-parietal and fronto-limbic correlates of socially reinforced learning, with specific temporo-parietal associations in behavioural variant frontotemporal dementia and predominantly fronto-limbic regions in Alzheimer's disease. In contrast, non-socially reinforced learning was consistently linked to medial temporal/hippocampal regions. No associations with cortical volume were found in Parkinson's disease. Results are consistent with core social deficits in behavioural variant frontotemporal dementia, subtle disruptions in ongoing feedback-mechanisms and social processes in Parkinson's disease and generalized learning alterations in Alzheimer's disease. This multimodal approach highlights the impact of different neurodegenerative profiles on learning and social feedback. Our findings inform a promising theoretical and clinical agenda in the fields of social learning, socially reinforced learning and neurodegeneration.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, PaulaObjectives: 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 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.