ABSTRACT
PURPOSE: To demonstrate 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 specificity (DSe) and sensitivity (DSe) 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 standards using 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 genomic dual 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 statistics within 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-19 , SARS-CoV-2 , COVID-19/diagnosis , COVID-19/epidemiology , Humans , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , RNA, Viral/genetics , SARS-CoV-2/genetics , Sensitivity and SpecificityABSTRACT
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus, was first identified after a cluster of cases in Wuhan, China in December 2019. Whether vertical transmission or placental pathology might occur following maternal infection during pregnancy remains unknown. This review aimed to summarise all studies that examined the placenta or neonates following infection with SARS-CoV-2, or closely related highly pathogenic coronavirus (SARS-CoV-1, or the Middle East respiratory syndrome coronavirus (MERS-CoV)). Structured literature searches found 50 studies that met the inclusion criteria. Twenty studies reported placental histopathology findings in third trimester placentas following maternal SARS-CoV-2 infection. Using the Amsterdam Consensus criteria to categorise the histopathology results, evidence of both fetal vascular malperfusion (35.3% of cases; 95% Confidence Interval (CI) 27.7-43.0%) and maternal vascular malperfusion (46% of cases; 95% CI 38.0-54.0%) were reported, along with evidence of inflammation in the placentas (villitis 8.7% cases, intervillositis 5.3% of cases, chorioamnionitis 6% of cases). The placental pathologies observed in SARS-CoV-2 were consistent with findings following maternal SARS-CoV-1 infection. Of those tested, a minority of neonates (2%) and placental samples tested positive for SARS-CoV-2 infection (21%). Limited conclusions can be drawn about the effect of maternal SARS-CoV-2 infection on placental pathology as most lack control groups and the majority of reports followed third trimester infection. Collaboration to maximise the number of samples examined will increase the reliability and generalisability of findings. A better understanding of the association between maternal SARS-CoV-2 infection and placental pathology will inform maternity care during the coronavirus pandemic.