Clinical evaluation of a RT-LAMP SARS-CoV-2 test for the Point-Of-Care, rapid, low-cost, integrating sample solid phase extraction and on which reagents are lyophilized.

ObjectivesDetermine the sensitivity and specificity of a Point-Of-Care test ( COVIDISC) for SARS-COV2. The novelty of the test is to integrate, on the same (low-cost) compact plastic/paper device, solid phase RNA extraction and RT-LAMP amplification, all reagents being freeze-dried on it. MethodRetrospective study with a cohort of 99 patients characterized by real-time RT-PCR. The 37 positive naso-pharyngeal samples cover a broad range of viral loads (from 5 gc /{micro}L to 2 106 gc/ {micro}L of sample). ResultsThe COVIDISC found 36 positives (out of 37 by IP4 RT-PCR protocols) and 63 negatives (out of 62 by RT-PCR). ConclusionThe sensitivity of the COVIDISC, found in this 99-patient retrospective study, is 97% and the specificity 100%.

Design of Specific Primer Sets for the Detection of B.1.1.7, B.1.351 and P.1 SARS-CoV-2 Variants using Deep Learning

As the COVID-19 pandemic continues, new SARS-CoV-2 variants with potentially dangerous features have been identified by the scientific community. Variant B.1.1.7 lineage clade GR from Global Initiative on Sharing All Influenza Data (GISAID) was first detected in the UK, and it appears to possess an increased transmissibility. At the same time, South African authorities reported variant B.1.351, that shares several mutations with B.1.1.7, and might also present high transmissibility. Earlier this year, a variant labelled P.1 with 17 non-synonymous mutations was detected in Brazil. Recently the World Health Organization has raised concern for the variants B.1.617.2 mainly detected in India but now exported worldwide. It is paramount to rapidly develop specific molecular tests to uniquely identify new variants. Using a completely automated pipeline built around deep learning and evolutionary algorithms techniques, we designed primer sets specific to variants B.1.1.7, B.1.351, P.1 and respectively. Starting from sequences openly available in the GISAID repository, our pipeline was able to deliver the primer sets for each variant. In-silico tests show that the sequences in the primer sets present high accuracy and are based on 2 mutations or more. In addition, we present an analysis of key mutations for SARS-CoV-2 variants. Finally, we tested the designed primers for B.1.1.7 using RT-PCR. The presented methodology can be exploited to swiftly obtain primer sets for each new variant, that can later be a part of a multiplexed approach for the initial diagnosis of COVID-19 patients.