The current reliable recommended test for coronavirus disease 2019 (COVID‐19) diagnosis is quantitative reverse‐transcription polymerase chain reaction (RT‐qPCR). Rapid antigen test devices could be useful as they are less expensive, faster without the need of specialized laboratories to perform the test. We report the performances of two rapid immunochromatographic antigen testing devices compared with RT‐qPCR for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) detection in nasopharyngeal samples. We carried out a lateral‐flow tests study on 401 nasopharyngeal swab samples from nonduplicated suspected COVID‐19 subjects. An equal volume of universal transport medium tubes‐containing samples (dilution ratio = 1:15) were added to the manufacturer's extraction buffer solution (dilution ratio = 1:2) and analyzed on BioSpeedia COVID19Speed‐Antigen Test and on Abbott Panbio™ COVID‐19 Ag Rapid Test, devices. Qualitative results were compared to those obtained by the RT‐qPCR (Allplex™ SARS‐CoV‐2 Assay Seegene). Based on our data, the overall sensitivity for BioSpeedia and Panbio devices was estimated at 65.5% and 75.0%, respectively. The sensitivity was greater for cycle threshold values less than 25 achieving 90.4 and 96.8 for BioSpeedia and Panbio devices, respectively. A perfect specificity of 100.0% was observed for both devices.
Rapid and recurrent breakthroughs of new SARS-CoV-2 strains (variants) have prompted public health authorities worldwide to set up surveillance networks to monitor the circulation of variants of concern. The use of next-generation sequencing technologies has raised the need for quality control assessment as required in clinical laboratories. The present study is the first to propose a validation guide for SARS-CoV-2 typing using three different NGS methods fulfilling ISO15189 standards. These include the assessment of the risk, specificity, accuracy, reproducibility, and repeatability of the methods. Among the three methods used, two are amplicon-based involving reverse transcription polymerase chain reaction (Artic v3 and Midnight v1) on Oxford Nanopore Technologies while the third one is amplicon-based using reverse complement polymerase chain reaction (Nimagen) on Illumina technology. We found that all methods met the quality requirement (e.g., 100% concordant typing results for accuracy, reproducibility, and repeatability) for SARS-CoV-2 typing in clinical setting. Additionally, the typing results emerging from each of the three sequencing methods were compared using three widely known nomenclatures (WHO, Pangolineage, and Nextclade). They were also compared regarding single nucleotide variations. The outcomes showed that Artic v3 and Nimagen should be privileged for outbreak investigation as they provide higher quality results for samples that do not meet inclusion criteria for analysis in a clinical setting. This study is a first step towards validation of laboratory developed NGS tests in the context of the new European regulation for medical devices and in vitro diagnostics.
« Thiverval a strain was injected into 10 sows at the 2 nd or 3 rd month of pregnancy. The strain has no unfavorable effects on the development of pregnancy or on the quality of the offspring. Fully immunocompetent at birth, the piglet is only protected after ingestion of maternel colostrum. However, this passive immunity is antagonistic to an active specific immunization. In the field practice, the vaccination of piglets takes place late, after disappearance of the passive antibodies which results in a more susceptible period in the animals'life, before and during weaning.This paper presents some preliminary experiments which show that an active immune response against a proteic antigen, lysozyme, has been induced in piglets presenting a high specific colostral immunity.In the purpose of a continuous protection of pigs all along their life, our results offer the possibi vaccinations very soonlity of after birth, whatever the immunological status of the animal.
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