A highly effective reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay for the rapid detection of SARS-CoV-2 infection

The COVID-19 pandemic has illustrated the importance of simple, rapid and accurate diagnostic testing. This study describes the validation of a new rapid SARS-CoV-2 RT-LAMP assay for use on extracted RNA or directly from swab offering an alternative diagnostic pathway that does not rely on traditional reagents that are often in short supply during a pandemic. Analytical specificity (ASp) of this new RT-LAMP assay was 100% and analytical sensitivity (ASe) was between 1 × 101 and 1 × 102 copies per reaction when using a synthetic DNA target. The overall diagnostic sensitivity (DSe) and specificity (DSp) of RNA RT-LAMP was 97% and 99% respectively, relative to the standard of care rRT-PCR. When a CT cut-off of 33 was employed, above which increasingly evidence suggests there is a low risk of patients shedding infectious virus, the diagnostic sensitivity was 100%. The DSe and DSp of Direct RT-LAMP (that does not require RNA extraction) was 67% and 97%, respectively. When setting CT cut-offs of ≤33 and ≤25, the DSe increased to 75% and 100%, respectively, time from swab-to-result, CT < 25, was < 15 min. We propose that RNA RT-LAMP could replace rRT-PCR where there is a need for increased sample throughput and Direct RT-LAMP as a near-patient screening tool to rapidly identify highly contagious individuals within emergency departments and care homes during times of increased disease prevalence ensuring negative results still get laboratory confirmation.</p

Moving versus stopped motor vehicle screen use: Engagement, perceptions, and correlates

Research on texting while driving routinely does not distinguish between drivers’ moving (while actively driving) and stopped (e.g., while at a red light) screen use behavior, but these behaviors conceptually differ in risk. The purpose of this study was to analyze differences in the prevalence, evaluations, and correlates of moving versus stopped motor vehicle screen use (MVSU). Participants were 236 adults (Mage = 35.36; 71% female) representing 31 U.S. states. Results indicate that individuals perceive and evaluate moving and stopped motor vehicle screen use (MVSU) differently, as well as engage in these behaviors at different rates. Compared to moving MVSU, participants engaged in stopped MVSU more frequently, felt more efficacious and less guilty about such behavior, and evaluated it as less risky, more acceptable, and as less reflective of moral values. Although levels of stopped versus moving MVSU were strongly correlated, larger differences in evaluations of stopped versus moving MVSU were associated with weaker correlations between engaging in the two MVSU behaviors. Participant age, race, and gender also moderated associations between stopped and moving MVSU

Reverse-Transcriptase Loop-Mediated Isothermal Amplification Has High Accuracy for Detecting Severe Acute Respiratory Syndrome Coronavirus 2 in Saliva and Nasopharyngeal/Oropharyngeal Swabs from Asymptomatic and Symptomatic Individuals.

Previous studies have described reverse-transcriptase loop-mediated isothermal amplification (RT-LAMP) method for the rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in nasopharyngeal and oropharyngeal swab and saliva samples. This study describes the validation of an improved sample preparation method for extraction-free RT-LAMP and defines the clinical performance of four different RT-LAMP assay formats for detection of SARS-CoV-2 within a multisite clinical evaluation. Direct RT-LAMP was performed on 559 swabs and 86,760 saliva samples and RNA RT-LAMP on extracted RNA from 12,619 swabs and 12,521 saliva samples from asymptomatic and symptomatic individuals across health care and community settings. For direct RT-LAMP, overall diagnostic sensitivity (DSe) of 70.35% (95% CI, 63.48%-76.60%) on swabs and 84.62% (95% CI, 79.50%-88.88%) on saliva was observed, with diagnostic specificity of 100% (95% CI, 98.98%-100.00%) on swabs and 100% (95% CI, 99.72%-100.00%) on saliva when compared with RT-qPCR; analyzing samples with RT-qPCR ORF1ab C values of ≤25 and ≤33, DSe values of 100% (95% CI, 96.34%-100%) and 77.78% (95% CI, 70.99%-83.62%) for swabs were observed, and 99.01% (95% CI, 94.61%-99.97%) and 87.61% (95% CI, 82.69%-91.54%) for saliva, respectively. For RNA RT-LAMP, overall DSe and diagnostic specificity were 96.06% (95% CI, 92.88%-98.12%) and 99.99% (95% CI, 99.95%-100%) for swabs, and 80.65% (95% CI, 73.54%-86.54%) and 99.99% (95% CI, 99.95%-100%) for saliva, respectively. These findings demonstrate that RT-LAMP is applicable to a variety of use cases, including frequent, interval-based testing of saliva with direct RT-LAMP from asymptomatic individuals who may otherwise be missed using symptomatic testing alone

RT-LAMP has high accuracy for detecting SARS-CoV-2 in saliva and naso/oropharyngeal swabs from asymptomatic and symptomatic individuals

Objectives: To validate an improved sample preparation method for extraction free Direct RT-LAMP and define the clinical performance of four different RT-LAMP assay formats for detection of SARS-CoV-2 with a multisite clinical evaluation.Method: We describe Direct RT-LAMP on 559 swabs and 86,760 saliva samples and RNA RT-LAMP on extracted RNA from 12,619 swabs and 12,521 saliva samples collected from asymptomatic and symptomatic individuals across multiple healthcare and community settings.Results: For Direct RT-LAMP, we found a diagnostic sensitivity (DSe) of 70.35% (95% CI 63.48-76.60%) on swabs and 84.62% (79.50-88.88%) on saliva, with diagnostic specificity (DSp) of 100% (98.98-100.00%) on swabs and 100% (99.72-100.00%) on saliva when compared to RT-qPCR. Analysing samples with RT-qPCR ORF1ab CT values of≤25 and ≤33 (high and medium-high viral copy number, respectively), we found DSe of 100% (96.34-100%) and 77.78% (70.99-83.62%) for swabs, and 99.01% (94.61-99.97%) and 87.32% (80.71-92.31%) for saliva. For RNA RT-LAMP DSe and DSp were 95.98% (92.74-98.06%) and 99.99% (99.95-100%) for swabs, and 80.65% (73.54-86.54%) and 99.99% (99.95-100%) for saliva, respectively.Conclusions: The findings from these evaluations demonstrate that RT-LAMP testing of swabs and saliva is applicable to a variety of different use-cases, including frequent, interval-based testing of saliva from asymptomatic individuals via Direct RT-LAMP that may otherwise be missed using symptomatic testing alone.<br/