Background Polyclonal convalescent plasma may be obtained from donors who have recovered from coronavirus disease 2019 (Covid-19). The efficacy of this plasma in preventing serious complications in outpatients with recent-onset Covid-19 is uncertain. Methods In this multicenter, double-blind, randomized, controlled trial, we evaluated the efficacy and safety of Covid-19 convalescent plasma, as compared with control plasma, in symptomatic adults (≥18 years of age) who had tested positive for severe acute respiratory syndrome coronavirus 2, regardless of their risk factors for disease progression or vaccination status. Participants were enrolled within 8 days after symptom onset and received a transfusion within 1 day after randomization. The primary outcome was Covid-19–related hospitalization within 28 days after transfusion. Results Participants were enrolled from June 3, 2020, through October 1, 2021. A total of 1225 participants underwent randomization, and 1181 received a transfusion. In the prespecified modified intention-to-treat analysis that included only participants who received a transfusion, the primary outcome occurred in 17 of 592 participants (2.9%) who received convalescent plasma and 37 of 589 participants (6.3%) who received control plasma (absolute risk reduction, 3.4 percentage points; 95% confidence interval, 1.0 to 5.8; P=0.005), which corresponded to a relative risk reduction of 54%. Evidence of efficacy in vaccinated participants cannot be inferred from these data because 53 of the 54 participants with Covid-19 who were hospitalized were unvaccinated and 1 participant was partially vaccinated. A total of 16 grade 3 or 4 adverse events (7 in the convalescent-plasma group and 9 in the control-plasma group) occurred in participants who were not hospitalized. Conclusions In participants with Covid-19, most of whom were unvaccinated, the administration of convalescent plasma within 9 days after the onset of symptoms reduced the risk of disease progression leading to hospitalization. (Funded by the Department of Defense and others; CSSC-004 ClinicalTrials.gov number, NCT04373460 .)

BACKGROUND: The efficacy of polyclonal high titer convalescent plasma to prevent serious complications of COVID-19 in outpatients with recent onset of illness is uncertain. METHODS: This multicenter, double-blind randomized controlled trial compared the efficacy and safety of SARS-CoV-2 high titer convalescent plasma to placebo control plasma in symptomatic adults >18 years positive for SARS-CoV-2 regardless of risk factors for disease progression or vaccine status. Participants with symptom onset within 8 days were enrolled, then transfused within the subsequent day. The measured primary outcome was COVID-19-related hospitalization within 28 days of plasma transfusion. The enrollment period was June 3, 2020 to October 1, 2021. RESULTS: A total of 1225 participants were randomized and 1181 transfused. In the pre-specified modified intention-to-treat analysis that excluded those not transfused, the primary endpoint occurred in 37 of 589 (6.3%) who received placebo control plasma and in 17 of 592 (2.9%) participants who received convalescent plasma (relative risk, 0.46; one-sided 95% upper bound confidence interval 0.733; P=0.004) corresponding to a 54% risk reduction. Examination with a model adjusting for covariates related to the outcome did not change the conclusions. CONCLUSION: Early administration of high titer SARS-CoV-2 convalescent plasma reduced outpatient hospitalizations by more than 50%. High titer convalescent plasma is an effective early outpatient COVID-19 treatment with the advantages of low cost, wide availability, and rapid resilience to variant emergence from viral genetic drift in the face of a changing pandemic.

Excessive aldosterone secretion is detrimental to the heart, vessels and kidneys, contributing to hypertension and the signs and progression of heart failure. Aldosterone secretion, abnormally elevated in heart failure and hypertension, can be blunted with angiotensin-converting enzyme inhibitors. Amlodipine, used to treat hypertension and heart failure, was hypothesized to activate the renin-angiotensin-aldosterone system (RAAS). A study was conducted with six normal adult male beagle dogs. Each dog received amlodipine (0.57 mg/kg b.i.d.) for 6 days, followed by amlodipine (0.57 mg/kg b.i.d.) and enalapril (0.57 mg/kg b.i.d.) for 4 days. Blood pressure, heart rate, serum chemistries and urinary aldosterone excretion, as a measure of RAAS activation, were compared with baseline values. Blood pressure fell by approximately 7% with amlodipine (P = 0.05) and a further 7% with the combination of amlodipine and enalapril (P < 0.01). Blood urea nitrogen increased with the combination (P < 0.05) but only one dog became mildly azotemic. Renin-angiotensin-aldosterone system activation, based on 24 h urinary aldosterone excretion and by aldosterone:creatinine ratio was increased by approximately threefold (P < 0.05) with amlodipine administration. This effect was blunted by enalapril, such that aldosterone excretion was no longer different from that observed under control conditions, although values for 24-h aldosterone excretion did not return to pretreament levels.

Results suggest that Boxers with cardiomyopathy and left ventricular dysfunction frequently have arrhythmias of supraventricular or ventricular origin. Whether ventricular dysfunction was preceded by electrical disturbances could not be determined from these data, and the natural history of myocardial disease in Boxers requires further study.

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