ABSTRACT
Purpose: Todemonstrate the diagnostic performance of rapid SARS-CoV-2 RT-LAMP assays, comparing the performance of genomic versus sub-genomic sequence target with subsequent application in an asymptomatic screening population. Methods: : RT-LAMP diagnostic sensitivity (DSe) and specificity (DSp) was determined using 114 RT-PCR clinically positive and 88 RT-PCR clinically negative swab samples processed through the diagnostic RT-PCR service within the University Hospitals of Leicester NHS Trust. A swab-based RT-LAMP SARS-CoV-2 screening programme was subsequently made available to all staff and students at the University of Leicester (Autumn 2020), implemented to ISO 15189:2012 standardsusing NHS IT infrastructure and supported by University Hospital Leicester via confirmatory NHS diagnostic laboratory testing of RT-LAMP ‘positive’ samples. Results: : Validation samples reporting a Ct < 20 were detected at 100% DSe and DSp, reducing to 95% DSe (100% DSp) for all samples reporting a Ct < 30 (both genomicdual sub-genomic assays). Advisory screening identified nine positive cases in 1680 symptom free individuals (equivalent to 540 cases per 100,000) with results reported back to participants and feed into national statisticswithin 48 hours. Conclusion: This work demonstrates the utility of a rapid RT-LAMP assay for collapsing transmission of SARS-CoV-2 in an asymptomatic screening population.
Subject(s)
COVID-19ABSTRACT
This study demonstrates the diagnostic performance of SARS-CoV-2 RT-LAMP assays, comparing the performance of genomic versus sub-genomic sequence target with subsequent application in an asymptomatic screening population. An RT-LAMP workflow was developed using synthetic positive control RNA and the diagnostic sensitivity and specificity was then determined using clinical patient samples processed through the diagnostic RT-PCR service within the University Hospitals of Leicester NHS Trust. 92 RT-PCR clinically positive and 88 RT-PCR clinically negative swab samples along with 78 clinically positive and 63 clinically negative saliva samples were equally detected at 100% DSe and 100% DSp for all samples reporting a Ct < 20. DSe for all samples reporting a Ct < 30 reduced slightly to around 95% (100% DSp) for both the single genomic (large open reading frame; orf1a) and dual sub-genomic (nucleocapsid plus envelope) targeting RT-LAMP assays. Lastly, the diagnostic performance of a saliva direct workflow was only about 50% that of the saliva RNA extraction workflow. Subsequently, a swab based RNA -RT-LAMP assay was implemented to ISO 15189:2012 standards supporting an advisory COVID-19 screening program for staff and students at the University of Leicester between October and December 2020. Within a 24-hour period, total nucleic acid extraction was followed by genomic target RT-LAMP plus an internal total RNA control to mitigate the possibility of false negative reporting. SARS-CoV-2 RT-LAMP positive samples were confirmed by an RT-PCR test in an NHS diagnostic laboratory and results were included within national statistics. Nine confirmed positive samples were detected in 1680 symptom free individuals (equivalent to 540 cases per 100,000) thus demonstrating the utility of RT-LAMP molecular diagnostic tool for the detection of SARS-CoV-2 in an asymptomatic population.
Subject(s)
COVID-19ABSTRACT
Background: Aspirin has been proposed as a treatment for COVID-19 on the basis of its antithrombotic properties. Methods: In this randomised, controlled, open-label trial, several possible treatments were compared with usual care in patients hospitalised with COVID-19. Eligible and consenting adults were randomly allocated in a 1:1 ratio to either usual standard of care alone or usual standard of care plus 150mg aspirin once daily until discharge using web-based simple (unstratified) randomisation with allocation concealment. The primary outcome was 28-day mortality. The trial is registered with ISRCTN (50189673) and clinicaltrials.gov (NCT04381936). Findings: Between 01 November 2020 and 21 March 2021, 7351 patients were randomly allocated to receive aspirin and 7541 patients to receive usual care alone. Overall, 1222 (17%) patients allocated to aspirin and 1299 (17%) patients allocated to usual care died within 28 days (rate ratio 0.96; 95% confidence interval [CI] 0.89-1.04; p=0.35). Consistent results were seen in all pre-specified subgroups of patients. Patients allocated to aspirin had a slightly shorter duration of hospitalisation (median 8 days vs. 9 days) and a higher proportion were discharged from hospital alive within 28 days (75% vs. 74%; rate ratio 1.06; 95% CI 1.02-1.10; p=0.0062). Among those not on invasive mechanical ventilation at baseline, there was no significant difference in the proportion meeting the composite endpoint of invasive mechanical ventilation or death (21% vs. 22%; risk ratio 0.96; 95% CI 0.90-1.03; p=0.23). Aspirin use was associated with an absolute reduction in thrombotic events of 0.6% (SE 0.4%) and an absolute increase in clinically significant bleeding of 0.6% (SE 0.2%). Interpretation: In patients hospitalised with COVID-19, aspirin was not associated with reductions in 28-day mortality or in the risk of progressing to invasive mechanical ventilation or death but was associated with a small increase in the rate of being discharged alive.