ABSTRACT
From 2018 to 2022, on average, 70% of the Brazilian effective electric generation was produced by hydropower, 10% by wind power, and 20% by thermal power plants. Over the last five years, Brazil suffered from a series of severe droughts. As a result, hydropower generation was reduced, but demand growth was also declined as results of the COVID-19 pandemic and economic recession. From 2012 to 2022, the Brazilian reservoir system operated with, on average, only 40% of the active storage, but storage recovered to normal levels in the first three months of 2022. Despite large capacity of storage reservoirs, high volatility of the marginal cost of energy was observed in recent years. In this paper, we used two optimization models, NEWAVE and HIDROTERM for our study. These two models were previously developed for mid-range planning of the operation of the Brazilian interconnected power system. We used these two models to optimize the operation and compared the results with observed operational records for the period of 2018-2022. NEWAVE is a stochastic dual dynamic programming model which aggregates the system into four subsystems and 12 equivalent reservoirs. HIDROTERM is a nonlinear programming model that considers each of the 167 individual hydropower plants of the system. The main purposes of the comparison are to assess cooperation opportunities with the use of both models and better understand the impacts of increasing uncertainties, seasonality of inflows and winds, demand forecasts, decisions about storage in reservoirs, and thermal production on energy prices. © World Environmental and Water Resources Congress 2023.All rights reserved
ABSTRACT
Background: Sotrovimab is a pan-sarbecovirus monoclonal antibody clinically evaluated for prevention of progression of COVID-19 in high-risk patients early in the course of infection. We investigated the rate of prevention of hospitalization or death by baseline anti-SARS-CoV-2 serostatus. Methods: COMET-ICE (NCT04545060) was a multicenter, double-blind, Phase III trial in nonhospitalized adults with symptomatic COVID-19 and ≥1 risk factor for disease progression. Participants were randomized 1:1 to an IV infusion of sotrovimab 500 mg or placebo. The primary efficacy endpoint was all-cause hospitalization >24 hours or death due to any cause within 29 days. Anti-nucleocapsid SARS-CoV-2 antibody was measured by the Abbott SARS-CoV-2 IgG assay run on the Architect i2000SR immunoassay analyzer. Results: In the final dataset (N=1057), the adjusted relative risk (RR) reduction in all-cause hospitalization or death due to any cause in the sotrovimab group compared to the placebo group was 79% (p<0.001) at Day 29. 70% and 19% of participants were seronegative and seropositive for anti-nucleocapsid protein at baseline, respectively. 11% of participants had unknown antibody status and were excluded. In the seronegative subgroup, 4/365 (1%) participants in the sotrovimab group met the primary endpoint compared to 26/375 (7%) in the placebo group (84% reduction in risk [RR: 0.16;95% CI: 0.06, 0.45]). Of the 4 seronegative participants who received sotrovimab and met the primary endpoint, 1 participant was hospitalized for small intestinal obstruction that was likely unrelated to COVID-19. Two of the 26 seronegative participants in the placebo arm who met the primary endpoint died compared to no deaths in the sotrovimab group. In the seropositive subgroup, conclusions are limited by small numbers. Numerically fewer participants in the sotrovimab group (2/105, 2%) were hospitalized compared to the placebo group (4/97, 4%). Importantly, both hospitalized seropositive participants in the sotrovimab group had an alternative reason for their hospitalization that was likely unrelated to COVID-19 (diabetic foot ulcer, non-small cell lung cancer). Progression rates in the sotrovimab arm were low and similar regardless of serostatus (1% seronegative, 2% seropositive). Safety profile by serostatus was consistent with that reported in the overall population. Conclusion: Sotrovimab appeared to consistently reduce the likelihood of a COVID-19-related hospitalization or death regardless of baseline serostatus.
ABSTRACT
Background. COVID-19 disproportionately results in hospitalization and death in older patients and those with underlying comorbidities. Sotrovimab is a pan-sarbecovirus monoclonal antibody that binds a highly conserved epitope of the SARSCoV-2 receptor binding domain and has an Fc modification that increases half-life. Sotrovimab retains activity against UK, S. Africa, Brazil, India, New York and California variants in vitro. Objectives. To evaluate the efficacy and safety of treatment with sotrovimab in high-risk, non-hospitalized patients with mild/moderate COVID-19, as part of the COMET-ICE clinical trial. Methods. Multicenter, double-blind, phase 3 trial in non-hospitalized patients with symptomatic COVID-19 and ≥1 risk factor for disease progression were randomized 1:1 to an IV infusion of sotrovimab 500 mg or placebo. The primary efficacy endpoint was the proportion of patients with COVID-19 progression, defined as hospitalization > 24 hours or death, due to any cause, ≤29 days of randomization. Results. The study met the pre-defined primary efficacy endpoint in a preplanned interim analysis: the risk of COVID-19 progression was significantly reduced by 85% (97.24% CI, 44% to 96%;P = 0.002) in 583 patients. In the final intention-to-treat analysis (N = 1057), the adjusted relative risk reduction was 79% (95% CI, 50% to 91%;p< 0.001) through Day 29 in recipients of sotrovimab (n=528) vs. placebo (n=529). Treatment with sotrovimab (ITT) resulted in a numerical reduction in the need for ER visits for illness management, hospitalization for acute illness management (any duration) or death (any cause) compared to placebo. No participants on sotrovimab required ICU admission, compared to 9 participants on placebo, of whom 4 participants required mechanical ventilation. No participants who received sotrovimab died, compared to 4 participants on placebo. The incidence of adverse events was similar between treatment arms and SAEs were numerically more common in the placebo arm. Conclusion. Treatment with sotrovimab 500 mg IV resulted in a clinically and statistically significant reduction in progression of COVID-19 to hospitalization or death in patients with mild/moderate disease and was well-tolerated.
ABSTRACT
Hydropower has been the predominant source of electrical energy supply in Brazil, with significant increasing participation share of thermal and wind power plants. From 2000 to 2012, on average, 91% of Brazilian effective electric generation was provided by hydropower, while the reservoir system operated, on average, at 68% of the active storage. From 2013 to 2020, 73% was supplied by hydropower plants, with only 39% of active storage. Demand increase, delays in expanding the system, and a series of moderate to severe droughts occurred in Brazil over the last eight years have contributed to bringing the power system to its current state of low storage levels and intense dispatch of the thermal plants. The COVID-19 pandemic in 2020 hit the country hard and brought an abrupt reduction in energy demand, with persistent impacts expected for the coming years. On average, 7.5 GW or 9.7% reduction is expected for the next three years in power demand. To deal with the reduction in demand, a well-planned adaptation strategy is urgently needed. It is important to plan how to efficiently combine reduction of dispatching the most expensive thermal plants and recover water levels of reservoir storage and productivity in the complex hydrosystem with over 150 reservoirs. To determine the tradeoff and adaptation strategy, we use the HIDROTERM model, a nonlinear programming optimization model previously developed for planning the operation of the Brazilian hydrothermal system for analysis by comparing results with demand forecasts before and during the pandemic and under different hydrological scenarios. © ASCE.