Evaluation of the performance of multiple immunoassay diagnostic platforms on the National Microbiology Laboratory SARS-CoV-2 National Serology Panel.

BACKGROUND: Serological assays designed to detect SARS-CoV-2 antibodies are being used in serological surveys and other specialized applications. As a result, and to ensure that the outcomes of serological testing meet high quality standards, evaluations are required to assess the performance of these assays and the proficiency of laboratories performing them. METHODS: A panel of 60 plasma/serum samples from blood donors who had reverse transcriptase-polymerase chain reaction (RT-PCR) confirmed SARS-CoV-2 infections and 21 SARS-CoV-2 negative samples were secured and distributed to interested laboratories within Canada (n = 30) and the United States (n = 1). Participating laboratories were asked to provide details on the diagnostic assays used, the platforms the assays were performed on, and the results obtained for each panel sample. Laboratories were blinded with respect to the expected outcomes. RESULTS: The performance of the different assays evaluated was excellent, with the high-throughput platforms of Roche, Ortho, and Siemens demonstrating 100% sensitivity. Most other high-throughput platforms had sensitivities of >93%, with the exception of the IgG assay using the Abbott ARCHITECT which had an average sensitivity of only 87%. The majority of the high-throughput platforms also demonstrated very good specificities (>97%). CONCLUSION: This proficiency study demonstrates that most of the SARS-CoV-2 serological assays utilized by provincial public health or hospital laboratories in Canada have acceptable sensitivity and excellent specificity.

HISTORIQUE: Les dosages sérologiques conçus pour dépister les anticorps anti-SRAS-CoV-2 sont utilisés dans les études sérologiques et d'autres applications spécialisées. Par conséquent, et pour s'assurer que leurs résultats respectent des normes de qualité, il faut procéder à des évaluations de leur performance et de la compétence des laboratoires à les effectuer. MÉTHODOLOGIE: Les chercheurs ont obtenu une batterie de 60 prélèvements de plasma et de sérum chez des donneurs dont l'amplification en chaîne par polymérase après transcription inverse (RT-PCR) avait confirmé des infections par le SRAS-CoV-2 et de 21 prélèvements dont les résultats étaient négatifs au SRAS-CoV-2 et les ont distribués aux laboratoires intéressés du Canada (n = 30) et des États-Unis (n = 1). Ils ont invité les laboratoires participants à fournir de l'information détaillée sur les dosages diagnostiques utilisés, les plateformes sur lesquelles les dosages étaient exécutés et les résultats obtenus pour chaque échantillon. Les chercheurs ont demandé aux laboratoires participants de fournir de l'information détaillée sur les dosages diagnostiques utilisés, les plateformes sur lesquelles les dosages ont été effectués, et les résultats obtenus à l'égard de chaque échantillon. Les laboratoires ont mené les études à l'insu des résultats escomptés. RÉSULTATS: Les divers dosages avaient une excellente exécution, les plateformes à haut débit de Roche, d'Ortho et de Siemens démontrant une sensibilité de 100 %. La plupart des autres plateformes à haut débit avaient des sensibilités de plus de 93 %, à l'exception des dosages des IgG faisant appel à l'analyseur ARCHITECT d'Abbott, dont la sensibilité moyenne était de seulement 87 %. La majorité des plateformes à haut débit avaient également une très bonne spécificité (plus de 97 %). CONCLUSION: La présente étude de compétence démontre que la plupart des dosages sérologiques du SRAS-CoV-2 évalués dans des laboratoires sanitaires provinciaux ou les laboratoires hospitaliers du Canada possèdent une sensibilité acceptable et une excellente spécificité.

Cross-Sectional Evaluation of Humoral Responses against SARS-CoV-2 Spike.

SARS-CoV-2 is responsible for the coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. The Spike glycoproteins of SARS-CoV-2 mediate viral entry and are the main targets for neutralizing antibodies. Understanding the antibody response directed against SARS-CoV-2 is crucial for the development of vaccine, therapeutic, and public health interventions. Here, we perform a cross-sectional study on 106 SARS-CoV-2-infected individuals to evaluate humoral responses against SARS-CoV-2 Spike. Most infected individuals elicit anti-Spike antibodies within 2 weeks of the onset of symptoms. The levels of receptor binding domain (RBD)-specific immunoglobulin G (IgG) persist over time, and the levels of anti-RBD IgM decrease after symptom resolution. Although most individuals develop neutralizing antibodies within 2 weeks of infection, the level of neutralizing activity is significantly decreased over time. Our results highlight the importance of studying the persistence of neutralizing activity upon natural SARS-CoV-2 infection.

Cross-sectional evaluation of humoral responses against SARS-CoV-2 Spike.

The SARS-CoV-2 virus is responsible for the current worldwide coronavirus disease 2019 (COVID-19) pandemic, infecting millions of people and causing hundreds of thousands of deaths. The Spike glycoprotein of SARS-CoV-2 mediates viral entry and is the main target for neutralizing antibodies. Understanding the antibody response directed against SARS-CoV-2 is crucial for the development of vaccine, therapeutic and public health interventions. Here we performed a cross-sectional study on 106 SARS-CoV-2-infected individuals to evaluate humoral responses against the SARS-CoV-2 Spike. The vast majority of infected individuals elicited anti-Spike antibodies within 2 weeks after the onset of symptoms. The levels of receptor-binding domain (RBD)-specific IgG persisted overtime, while the levels of anti-RBD IgM decreased after symptoms resolution. Some of the elicited antibodies cross-reacted with other human coronaviruses in a genus-restrictive manner. While most of individuals developed neutralizing antibodies within the first two weeks of infection, the level of neutralizing activity was significantly decreased over time. Our results highlight the importance of studying the persistence of neutralizing activity upon natural SARS-CoV-2 infection.

[Nursing in prison: inmates as patients]. / La pratique infirmière en milieu carcéral: des détenus pour patients.

There are very few studies investigating the work nurses do in prisons. Based on data stemming from a research in Psychodynamics of Work and a literature review, this paper describes nursing practices in a Canadian penitentiary institution. Three male nurses and two female nurses participated in three two-hour long focus group sessions. Central sources of pleasure that emerged from the focus groups were the scope of nursing care practice ; the autonomy and collaboration with physicians; nursing care practices devoid of moral value judgments, the humanitarian approach, caring and the wish to make a difference in the lives of the inmates ; the pride connected to this unusual professional context, and the recognition by peers and inmates. The main sources of suffering on the other hand were the feeling that rehabilitation was more an ideal than reality ; the paradox of providing both care and safety ; the scary characteristics of working alone ; the fear of lawsuits, and the feeling of being observed continuously. The resulting data we discuss show the issues of a certain dissociation that exists between the patient and the inmate, the fear of contamination of a healthcare nursing identity by the place of practice, but also the feeling of plenitude and sublimation. The conclusion stresses the tension that exists between security and caring, distance and proximity.

Human parvovirus 4 infection, Cameroon.

In a post hoc analysis of samples collected in 2009, we determined seroprevalence of parvovirus 4 (PARV4) among elderly Cameroonians. PARV4 seropositivity was associated with receipt of intravenous antimalarial drugs, intramuscular streptomycin, or an intramuscular contraceptive, but not hepatitis C virus seropositivity. Findings suggest parenteral acquisition of some PARV4 infections.

Transmission of hepatitis C virus among spouses in Cameroon and the Central African Republic.

Heterosexual transmission of hepatitis C virus (HCV) is uncommon, with few studies undertaken in Central Africa. To determine the frequency of inter-spouse HCV transmission, cross-sectional studies of elderly individuals in Ebolowa, Cameroon and Nola, Central African Republic, in which, respectively, 24 and 83 long-term couples had been identified, were examined further. Blood samples were tested for antibody to HCV. Anti-HCV positive samples were genotyped by phylogenetic analysis of a fragment of the NS5B gene. In Nola, 4 out of 9 (44.4%) wives of anti-HCV positive husbands and 1 out of 74 (1.4%) wives of anti-HCV negative husbands were anti-HCV positive (P < 0.001); in Ebolowa, the corresponding proportions were 10 out of 15 (66.7%) and 3 out of 9 (33.3%) (P = 0.21). After adjustment for age and site-specific risk factors of HCV infection, HCV seropositivity of the wives remained associated with their husbands' HCV serostatus, significantly so in Nola (P = 0.003) and marginally in Ebolowa (P = 0.06). In 7 out of 14 concordant seropositive couples, the genotype could be determined in both spouses. Four couples were infected with different genotypes, while three were infected with the same genotype. Thus, serological concordance between the spouses was related to a combination of infections acquired independently and inter-spouse transmission. It could not be determined whether inter-spouse transmission occurred sexually, through blood-blood contact, or otherwise. Inter-spouse transmission may have contributed to the high prevalence among elderly populations of Central Africa since some patients infected during healthcare subsequently transmitted the virus to their spouse.

Risk factors for hepatitis C virus transmission in colonial Cameroon.

BACKGROUND: In southern Cameroon, where SIV(cpz), the source of human immunodeficiency virus 1 (HIV-1) group M, is prevalent among wild chimpanzees, approximately 50% of some human birth cohorts have been infected with hepatitis C virus (HCV) through unclear mechanisms. METHODS: To evaluate indirectly the hypothesis that medical interventions contributed to the early emergence of HIV-1, we conducted a cross-sectional study of 451 inhabitants of Ebolowa in southern Cameroon aged 60 years, using HCV as a marker of parenteral transmission of blood-borne viruses. We administered a questionnaire and tested serum for antibodies against HCV. Viral gene sequences were obtained from HCV-positive sera. Molecular clock analyses provided an independent source of information on epidemic history. RESULTS: A total of 252 participants (56%) were HCV seropositive. HCV sequences were amplified and genotyped from 171 individuals. Independent risk factors for HCV seropositivity were older age, having received intravenous treatment against malaria, and having attended an ethnic school (women only), whereas having been circumcised by a traditional practitioner (men only) tended to be associated with HCV. In addition, transfusions were associated with HCV genotype 1 transmission. Molecular clock analyses of HCV genotypes 1, 2, and 4 revealed that each independently underwent exponential growth during the first half of the 20th century. CONCLUSIONS: Medical interventions (intravenous antimalarial drugs, transfusions) and to a lesser extent traditional practices (circumcision) were associated with the massive transmission of HCV among this population decades ago. This finding supports the hypothesis that medical interventions contributed to the transmission of blood-borne viruses, perhaps including SIV(cpz) and HIV-1, in the same region during the early 20th century.