BACKGROUND: Whole genome sequencing (WGS) of respiratory viruses from rapid antigen tests (RAT-WGS) is a novel approach to expanding genomic surveillance of respiratory infections. To date however, there are limited data on the genomic stability of these viruses on RATs. In this study, we investigated the effect of storage conditions and nucleic acid preservatives on the ability to enhance stability and improve recovery of respiratory virus genomes from RATs.
METHODS: A mixture of common respiratory viruses was used to inoculate RATs at different environmental temperatures (4°C, 20°C and 36°C), with two preservative reagents (RNALater and DNA/RNA shield) Nucleic acid was extracted from RATs at two different timepoints (72 h and seven days) and subject to real-time multiplex respiratory PCR to detect a range of respiratory viruses. WGS was performed using target-enrichment with the TWIST Comprehensive Viral Research Panel. Defined metrics from an automated in-house bioinformatic pipeline were used to assess and compare viral genome recovery under different conditions.
RESULTS: Nucleic acid degradation (indicated by relative change in PCR cycle threshold and WGS-based metrics) was most notable at 20 °C and 36 °C. Storage in either RNALater or DNA / RNA shield improved genome recovery for respiratory viruses across all temperature conditions, although this was most pronounced for RNALater. Subtyping of Influenza viruses demonstrated the applicability of RAT-WGS in downstream genomic epidemiological surveillance.
CONCLUSIONS: Under simulated conditions, RAT-WGS demonstrated that (i) viral genomes were generally stable at 4°C at 72 h and 1 week, (ii) RNALater has a more significant preservation of nucleic acids compared to DNA/RNA Shield and (iii) genome recovery can be achieved using a sequencing depth of 500,000 reads per sample in RNALater, across all respiratory viruses and conditions.

UNASSIGNED: While real-time reverse transcription PCR (RT-PCR) is the recommended laboratory method to diagnose severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infection, its use in resource limited settings can be difficult to maintain due to high testing demand and shortage of reagents. The aim of this study was to evaluate the performances of Realy Tech™ and Standard Q™ in comparison to RT-PCR in a relatively low COVID-19 prevalence setting, Mali.
UNASSIGNED: We conducted a cross-sectional study between January and April 2021 in Bamako and Kati regions to evaluate both rapid tests during a large SARS-CoV-2 prevalence study in Mali.
UNASSIGNED: Of the 390 samples tested, the sensitivity and specificity of Realy Tech™ and Standard Q™ were 57.1% (95%CI: 44.1-69.2), 95.8% (95%CI: 93.1-97.5); 61.9% (95%CI: 46.8-75.0), and 94.1% (95%CI: 89.5-96.8) respectively. Using RT-PCR, the global prevalence of SARS-CoV-2 was 14.4% (56/390). In both rapid antigen tests, the performance was better when used in suspected patients compared to positive patients under treatment. Moreover, higher viral loads equivalent to Ct < 25 were associated with better detection rates.
UNASSIGNED: While waiting for more complete data, these preliminary studies suggest that Realy Tech™ and Standard Q™ should not be used alone for COVID-19 diagnosis in Mali.

The COVID-19 pandemic resulted in the generation of large quantities of medical waste and highlighted the importance of efficient waste management systems. One good example of this is rapid antigen tests, which contain valuable resources, and which are usually incinerated after their use. The present study aimed to evaluate the potential of waste rapid antigen test cassettes (RATCs) as a resource for the preparation of sustainable flame-retardant plastics. Milled RATCs were compounded with different concentrations (10-30 wt.%) of aluminium diethylphosphinate (ADP) and injection moulded into test specimens. Prepared samples were exposed to ultraviolet (UV) ageing for varying durations and characterised by Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), tensile tests, Charpy impact tests, and vertical burning tests. FT-IR analysis revealed that RATCs are composed mainly of high-impact polystyrene (HIPS), which was further confirmed by suitable glass transition temperatures (Tg) determined by DSC and DMA. The addition of ADP resulted in progressive embrittlement of HIPS with increasing concentration, while flammability decreased significantly and reached V-1 classification at loading of 30 wt.%. UV ageing caused photo-oxidative degradation of HIPS, which resulted in decreased strain-at-break, while flammability was not affected.

OBJECTIVE: To investigate the potential impacts of optimizing coronavirus disease 2019 (COVID-19) rapid antigen test (RAT) self-testing diagnostic accuracy information.
METHODS: Online randomized experiment using hypothetical scenarios: in scenarios 1 to 3 (RAT result positive), the posttest probability was considered to be very high (likely true positives), and in scenarios 4 and 5 (RAT result negative), the posttest probability was considered to be moderately high (likely false negatives).
METHODS: December 12 to 22, 2022, during the mixed-variant Omicron wave in Australia.
METHODS: Australian adults. Intervention: diagnostic accuracy of a COVID-19 self-RAT presented in a health literacy-sensitive way; usual care: diagnostic accuracy information provided by the manufacturer; control: no diagnostic accuracy information.
METHODS: Intention to self-isolate.
RESULTS: A total of 226 participants were randomized (control n = 75, usual care n = 76, intervention n = 75). More participants in the intervention group correctly interpreted the meaning of the diagnostic accuracy information (P = 0.08 for understanding sensitivity, P < 0.001 for understanding specificity). The proportion who would self-isolate was similar across scenarios 1 to 3 (likely true positives). The proportion was higher in the intervention group than in the control for scenarios 4 and 5 (likely false negatives). These differences were not statistically significant. The largest potential effect was seen in scenario 5 (dinner party with confirmed cases, the person has symptoms, negative self-RAT result), with 63% of the intervention group and 49% of the control group indicating they would self-isolate (absolute difference 13.3%, 95% confidence interval: -2% to 30%, P = 0.10).
CONCLUSIONS: Health literacy sensitive formatting supported participant understanding and recall of diagnostic accuracy information. This may increase community intentions to self-isolate when there is a likely false-negative self-RAT result. Trial registration: Australia New Zealand Clinical Trial Registry (ACTRN12622001517763).
CONCLUSIONS: Community-based diagnostic accuracy studies of COVID-19 self-RATs indicate substantially lower sensitivity (and higher risk of false-negative results) than the manufacturer-supplied information on most government public Web sites.This online randomized study found that a health literacy-sensitive presentation of the imperfect diagnostic accuracy COVID-19 self-RATs supported participant understanding and recall of diagnostic accuracy information.Health literacy-sensitive presentation may increase community intentions to self-isolate after a negative test result where the posttest probability is still moderately high (i.e., likely false-negative result).To prevent the onward spread of infection, efforts to improve communication about the high risk of false-negative results from COVID-19 self-RATs are urgently needed.

We analysed the performance characteristics of the respiratory syncytial virus lateral flow rapid antigen assay in use when compared to a multiplex polymerase chain reaction for detection of respiratory viruses. The study was conducted at a tertiary paediatric hospital in Port Elizabeth, South Africa, from 01 January 2017 to 31 December 2018. We found the clinical sensitivity (36.8%) of the rapid test to be too low for routine diagnostic use. Knowledge of assay performance characteristics of rapid tests are important for appropriate interpretation of rapid test results.

The COVID-19 pandemic has transformed laboratory management, with a surge in demand for diagnostic tests prompting the adoption of new diagnostic assays and the spread of variant surveillance tools. Rapid antigen tests (RATs) were initially used only for screening and later as suitable infection assessment tools. This study explores the feasibility of sequencing the SARS-CoV-2 genome from the residue of the nasopharyngeal swab extraction buffers of rapid antigen tests (RATs) to identify different COVID-19 lineages and sub-lineages.
METHODS: Viral RNA was extracted from the residue of the nasopharyngeal swab extraction buffers of RATs and, after a confirmation of positivity through a reaction of RT-PCR, viral genome sequencing was performed.
RESULTS: Overall, the quality of the sequences obtained from the RNA extracted from the residue of the nasopharyngeal swab extraction buffers of RATs was adequate and allowed us to identify the SARS-CoV-2 variants\' circulation and distribution in a period when the use of molecular swabs had been drastically reduced.
CONCLUSIONS: This study demonstrates the potential for genomic surveillance by sequencing SARS-CoV-2 from the residue of the nasopharyngeal swab extraction buffers of RATs, highlighting alternative possibilities for tracking variants.

The nucleocapsid (N) protein is an abundant component of SARS-CoV-2 and a key analyte for lateral-flow rapid antigen tests. Here, we present new structural insights for the SARS-CoV-2 N protein using cryo-electron microscopy (EM) and molecular modeling tools. Epitope mapping based on structural data supported host-immune interactions in the C-terminal portion of the protein, while other regions revealed protein-protein interaction sites. Complementary modeling results suggested that N protein structures from known variants of concern (VOC) are nearly 100% conserved at specific antibody-binding sites. Collectively, these results suggest that rapid tests that target the nucleocapsid C-terminal domain should have similar accuracy across all VOCs. In addition, our combined structural modeling workflow may guide the design of immune therapies to counter viral processes as we plan for future variants and pandemics.

Many interventions for widescale distribution of rapid antigen tests for COVID-19 have utilized online, direct-to-consumer (DTC) ordering systems; however, little is known about the sociodemographic characteristics of home-test users. We aimed to characterize the patterns of online orders for rapid antigen tests and determine geospatial and temporal associations with neighborhood characteristics and community incidence of COVID-19, respectively.
This observational study analyzed online, DTC orders for rapid antigen test kits from beneficiaries of the Say Yes! Covid Test program from March to November 2021 in five communities: Louisville, Kentucky; Indianapolis, Indiana; Fulton County, Georgia; O\'ahu, Hawaii; and Ann Arbor/Ypsilanti, Michigan. Using spatial autoregressive models, we assessed the geospatial associations of test kit distribution with Census block-level education, income, age, population density, and racial distribution and Census tract-level Social Vulnerability Index. Lag association analyses were used to measure the association between online rapid antigen kit orders and community-level COVID-19 incidence.
In total, 164,402 DTC test kits were ordered during the intervention. Distribution of tests at all sites were significantly geospatially clustered at the block-group level (Moran\'s I: p < 0.001); however, education, income, age, population density, race, and social vulnerability index were inconsistently associated with test orders across sites. In Michigan, Georgia, and Kentucky, there were strong associations between same-day COVID-19 incidence and test kit orders (Michigan: r = 0.89, Georgia: r = 0.85, Kentucky: r = 0.75). The incidence of COVID-19 during the current day and the previous 6-days increased current DTC orders by 9.0 (95% CI = 1.7, 16.3), 3.0 (95% CI = 1.3, 4.6), and 6.8 (95% CI = 3.4, 10.2) in Michigan, Georgia, and Kentucky, respectively. There was no same-day or 6-day lagged correlation between test kit orders and COVID-19 incidence in Indiana.
Our findings suggest that online ordering is not associated with geospatial clustering based on sociodemographic characteristics. Observed temporal preferences for DTC ordering can guide public health messaging around DTC testing programs.

Diagnoses of infectious diseases are being transformed as mass self-testing using rapid antigen tests (RATs) is increasingly integrated into public health. Widely used during the COVID-19 pandemic, RATs are claimed to have many advantages over \'gold-standard\' polymerase chain reaction tests, especially their ease of use and production of quick results. Yet, while laboratory studies indicate the value of RATs in detecting the SARS-CoV-2 virus antigen, uncertainty surrounds their deployment and ultimate effectiveness in stemming infections. This article applies the analytic lens of biological citizenship (or bio-citizenship) to explore Australia\'s experience of implementing a RAT-based mass self-testing strategy to manage COVID-19. Drawing on Annemarie Mol\'s (1999, The Sociological Review, 47(1), 74-89) concept of ontological politics and analysing government statements, scientific articles and news media reporting published during a critical juncture of the strategy\'s implementation, we explore the kind of bio-citizenship implied by this strategy. Our analysis suggests the emergence of what we call liminal bio-citizenship, whereby citizens are made responsible for self-managing infection risk without the diagnostic certitude this demands. We discuss how the different realities of mass self-testing interact to reinforce this liminal citizenship and consider the implications for the sociology of diagnosis.

UNASSIGNED: Rapid antigen detection tests (Ag-RDT) for SARS-CoV-2 with emergency use authorization generally include a condition of authorization to evaluate the test\'s performance in asymptomatic individuals when used serially. We aim to describe a novel study design that was used to generate regulatory-quality data to evaluate the serial use of Ag-RDT in detecting SARS-CoV-2 virus among asymptomatic individuals.
UNASSIGNED: This prospective cohort study used a siteless, digital approach to assess longitudinal performance of Ag-RDT. Individuals over 2 years old from across the USA with no reported COVID-19 symptoms in the 14 days prior to study enrollment were eligible to enroll in this study. Participants throughout the mainland USA were enrolled through a digital platform between October 18, 2021 and February 15, 2022. Participants were asked to test using Ag-RDT and molecular comparators every 48 hours for 15 days. Enrollment demographics, geographic distribution, and SARS-CoV-2 infection rates are reported.
UNASSIGNED: A total of 7361 participants enrolled in the study, and 492 participants tested positive for SARS-CoV-2, including 154 who were asymptomatic and tested negative to start the study. This exceeded the initial enrollment goals of 60 positive participants. We enrolled participants from 44 US states, and geographic distribution of participants shifted in accordance with the changing COVID-19 prevalence nationwide.
UNASSIGNED: The digital site-less approach employed in the \"Test Us At Home\" study enabled rapid, efficient, and rigorous evaluation of rapid diagnostics for COVID-19 and can be adapted across research disciplines to optimize study enrollment and accessibility.