ABSTRACT
This research uses mathematically derived visual logistics to interpret COVID-19 molecular and rapid antigen test (RAgT) performance, determine prevalence boundaries where risk exceeds expectations, and evaluate benefits of recursive testing along home, community, and emergency spatial care paths. Mathematica and open access software helped graph relationships, compare performance patterns, and perform recursive computations. Tiered sensitivity/specificity comprise: (T1) 90%/95%; (T2) 95%/97.5%; and (T3) 100%/≥99%, respectively. In emergency medicine, median RAgT performance peaks at 13.2% prevalence, then falls below T1, generating risky prevalence boundaries. RAgTs in pediatric ERs/EDs parallel this pattern with asymptomatic worse than symptomatic performance. In communities, RAgTs display large uncertainty with median prevalence boundary of 14.8% for 1/20 missed diagnoses, and at prevalence > 33.3-36.9% risk 10% false omissions for symptomatic subjects. Recursive testing improves home RAgT performance. Home molecular tests elevate performance above T1 but lack adequate validation. Widespread RAgT availability encourages self-testing. Asymptomatic RAgT and PCR-based saliva testing present the highest chance of missed diagnoses. Home testing twice, once just before mingling, and molecular-based self-testing, help avoid false omissions. Community and ER/ED RAgTs can identify contagiousness in low prevalence. Real-world trials of performance, cost-effectiveness, and public health impact could identify home molecular diagnostics as an optimal diagnostic portal.
ABSTRACT
BACKGROUND: Remdesivir (RDV) was approved for treatment of coronavirus disease 2019 (COVID-19), in May 2020 under US Food and Drug Administration emergency use authorization (EUA). Clinical outcomes related to RDV use in hospitalized patients during the EUA period are not well described. METHODS: We conducted a retrospective study of patients who received RDV under EUA. The primary outcome was clinical recovery by day 14 as determined by an eight-category ordinal scale. Secondary outcomes included recovery and survival to day 28, and adverse events. Recovery and survival were calculated using a stratified log-rank Kaplan-Meier estimator and a Cox proportional hazards model. RESULTS: Overall, 164 patients received RDV between May and October 2020, and 153 (93.3%) had evaluable data. Most (77.1%) were hospitalized within 10 days of symptom onset, and 79.7% started RDV within 48 hours. By days 14 and 28, 96 (62.7%) and 117 patients (76.5%) met the definition of clinical recovery, respectively. Median time to recovery was 6 days [interquartile range (IQR) 4-12]. Mortality rates were 6.5% and 11.8% by days 14 and 28, respectively. Age and time to start of RDV after hospital admission were predictive of recovery and 28-day mortality. CONCLUSIONS: In this real-world experience, outcomes after 5 days of RDV therapy were comparable to those of clinical trials. Disease severity, age, and dexamethasone use influenced clinical outcomes. Time to RDV initiation appeared to affect recovery and 28-day mortality, a finding that should be explored further. Mortality rate decreased over the analysis period, which could be related to dexamethasone use and improved management of COVID-19.