Prediction of Symptomatic Severe Acute Respiratory Syndrome Coronavirus 2 Infection by Quantitative Digital Polymerase Chain Reaction Normalized to International Units.

Although numerous studies have evaluated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using cycle threshold (Ct) values as a surrogate of viral ribonucleic acid (RNA) load, few studies have used standardized, quantitative methods. We validated a quantitative SARS-CoV-2 digital polymerase chain reaction assay normalized to World Health Organization International Units and correlated viral RNA load with symptoms and disease severity.

covidscreen: a web app and R Package for assessing asymptomatic COVID-19 testing strategies.

BACKGROUND: COVID-19 has caused over 305 million infections and nearly 5.5 million deaths globally. With complete eradication unlikely, organizations will need to evaluate their risk and the benefits of mitigation strategies, including the effects of regular asymptomatic testing. We developed a web application and R package that provides estimates and visualizations to aid the assessment of organizational infection risk and testing benefits to facilitate decision-making, which combines internal and community information with malleable assumptions. RESULTS: Our web application, covidscreen, presents estimated values of risk metrics in an intuitive graphical format. It shows the current expected number of active, primarily community-acquired infections among employees in an organization. It calculates and explains the absolute and relative risk reduction of an intervention, relative to the baseline scenario, and shows the value of testing vaccinated and unvaccinated employees. In addition, the web interface allows users to profile risk over a chosen range of input values. The performance and output are illustrated using simulations and a real-world example from the employee testing program of a pediatric oncology specialty hospital. CONCLUSIONS: As the COVID-19 pandemic continues to evolve, covidscreen can assist organizations in making informed decisions about whether to incorporate covid test based screening as part of their on-campus risk-mitigation strategy. The web application, R package, and source code are freely available online (see "Availability of data and materials").

An adaptive, asymptomatic SARS-CoV-2 workforce screening program providing real-time, actionable monitoring of the COVID-19 pandemic.

COVID-19 remains a challenge worldwide, and testing of asymptomatic individuals remains critical to pandemic control measures. Starting March 2020, a total of 7497 hospital employees were tested at least weekly for SARS CoV-2; the cumulative incidence of asymptomatic infections was 5.64%. Consistently over a 14-month period half of COVID-19 infections (414 of 820, total) were detected through the asymptomatic screening program, a third of whom never developed any symptoms during follow-up. Prompt detection and isolation of these cases substantially reduced the risk of potential workplace and outside of workplace transmission. COVID-19 vaccinations of the workforce were initiated in December 2020. Twenty-one individuals tested positive after being fully vaccinated (3.9 per 1000 vaccinated). Most (61.9%) remained asymptomatic and in majority (75%) the virus could not be sequenced due to low template RNA levels in swab samples. Further routine testing of vaccinated asymptomatic employees was stopped and will be redeployed if needed; routine testing for those not vaccinated continues. Asymptomatic SARS-CoV-2 testing, as a part of enhanced screening, monitors local dynamics of the COVID-19 pandemic and can provide valuable data to assess the ongoing impact of COVID-19 vaccination and SARS-CoV-2 variants, inform risk mitigation, and guide adaptive, operational planning including titration of screening strategies over time, based on infection risk modifiers such as vaccination.

A nucleic acid amplification test-based strategy does not help inform return to work for healthcare workers with COVID-19.

OBJECTIVE: The objective of this study is to assess the utility of a nucleic acid amplification test-based approach to shorten isolation of healthcare workers (HCWs) with COVID-19 in the setting of the highly transmissible omicron variant. METHODS: Between December 24, 2021, and January 5, 2022, HCWs who tested positive for SARS-CoV-2 were retested with PCR at least 5 days since onset of symptoms. RESULTS: Forty-six sequential fully COVID-19 vaccinated HCWs who had tested positive for SARS-CoV-2 underwent follow-up testing. All the samples were confirmed as omicron variants and only four (8.7%) were negative in the follow-up test performed at a median of 6 (range 5-12) since onset of symptoms. CONCLUSIONS: Implementation of a test-based strategy is logistically challenging, increases costs, and did not lead to shorter isolation in our institution.

Multicenter evaluation of the NeuMoDx™ SARS-CoV-2 Test.

The SARS-CoV-2 virus has caused millions of confirmed COVID-19 cases worldwide and hundreds of thousands of deaths in less than 6 months. Mitigation measures including social distancing were implemented to control disease spread, however, thousands of new cases continue to be diagnosed daily. To resume some suspended social activities, early diagnosis and contact tracing are essential. To meet this required diagnostic and screening capacity, high throughput diagnostic assays are needed. The NeuMoDx™ SARS-CoV-2 assay, performed on a NeuMoDx molecular system, is a rapid, fully automated, qualitative real-time RT-PCR diagnostic test with throughput of up to 288 tests in an 8 -h shift. The assay received emergency use authorization from the FDA and is used in some large testing centers in the US. This paper describes the analytical and clinical performance of the assay at three centers: Johns Hopkins Hospital, St. Jude Children's Research Hospital, and the Wadsworth Center.