ABSTRACT
After the end of the first epidemic episode of SARS-CoV-2 infections, as cases began to rise again during the summer of 2020, we at IHU Méditerranée Infection in Marseille, France, intensified the genomic surveillance of SARS-CoV-2, and described the first viral variants. In this study, we compared the incidence curves of SARS-CoV-2-associated deaths in different countries and reported the classification of SARS-CoV-2 variants detected in our institute, as well as the kinetics and sources of the infections. We used mortality collected from a COVID-19 data repository for 221 countries. Viral variants were defined based on ≥5 hallmark mutations along the whole genome shared by ≥30 genomes. SARS-CoV-2 genotype was determined for 24,181 patients using next-generation genome and gene sequencing (in 47 and 11% of cases, respectively) or variant-specific qPCR (in 42% of cases). Sixteen variants were identified by analyzing viral genomes from 9,788 SARS-CoV-2-diagnosed patients. Our data show that since the first SARS-CoV-2 epidemic episode in Marseille, importation through travel from abroad was documented for seven of the new variants. In addition, for the B.1.160 variant of Pangolin classification (a.k.a. Marseille-4), we suspect transmission from farm minks. In conclusion, we observed that the successive epidemic peaks of SARS-CoV-2 infections are not linked to rebounds of viral genotypes that are already present but to newly introduced variants. We thus suggest that border control is the best mean of combating this type of introduction, and that intensive control of mink farms is also necessary to prevent the emergence of new variants generated in this animal reservoir.
ABSTRACT
BACKGROUND: With the persistent COVID-19 pandemic, there is an urgent need to use rapid and reliable diagnostic tools for highly urgent cases. Antigen tests are disappointing with their lack of sensitivity. Among molecular tools allowing a diagnosis in less than an hour, only one, the Cepheid Xpert Xpress SARS-CoV-2 assay, has exhibited a good sensitivity. However, we are also facing a global shortage of reagents and kits. Thus, it is imperative to evaluate other point-of-care molecular tests. METHODS: We evaluated the VitaPCR™ RT-PCR assay, whose sample analysis time is of approximately 20 min, in nasopharyngeal secretions from 534 patients presenting to our Institute, for the diagnosis of COVID-19, and compared it to our routine RT-PCR assay. We also compared the two assays with tenfold dilutions of a SARS-CoV-2 strain. RESULTS: Compared to our routine RT-PCR and the previous diagnosis of COVID-19, the sensitivity, specificity, positive and negative predictive values of VitaPCR™ can be evaluated to be 99.3 % (155/156), 94.7 % (358/378), 88.6 % (155/175) and 99.7 % (358/359), respectively. Tenfold dilutions of a SARS-CoV-2 strain show that the VitaPCR™ was more sensitive that our routine RT-PCR assay. CONCLUSION: The VitaPCR™ SARS-CoV-2 is an accurate rapid test, suitable for clinical practice that can be performed as part of a point-of-care testing, for the rapid diagnosis of COVID-19.