Proficiency Testing of Viral Marker Screening in African Blood Centers - Seven African Countries, 2017.

A 2014 report evaluating accuracy of serologic testing for transfusion-transmissible viruses at African blood center laboratories found sensitivities of 92%, 87%, and 90% for detecting infections with human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV), respectively (1). Following substantial investments in national blood transfusion service (NBTS) laboratories, in 2017 investigators tested proficiency at 84 blood center laboratories (29 NBTS and 55 non-NBTS) in seven African countries. A blinded panel of 25 plasma samples was shipped to each participating laboratory for testing with their usual protocols based on rapid diagnostic tests (RDTs) (2) and third and fourth generation enzyme immunoassays (EIA-3 and EIA-4). Sensitivity and specificity were estimated using separate regression models that clustered assays by laboratory and adjusted for assay type and NBTS laboratory status. Mean specificities were ≥95% for all three viruses; however, mean sensitivities were 97% for HIV-positive, 76% for HBV-positive, and 80% for HCV-positive samples. Testing sensitivities for all viruses were high when EIA-3 assays were used (≥97%). Lower sensitivities for HBV-positive samples and HCV-positive samples were associated with assay types other than EIA-3, used primarily by non-NBTS laboratories. Proficiency for HIV testing has improved following international investments, but proficiency remains suboptimal for HBV and HCV testing. In sub-Saharan African blood centers, the quality of rapid tests used for HBV and HCV screening needs to be improved or their use discouraged in favor of EIA-3 tests

Building capacities in research for blood services in Africa

Background: Capacity building of African based blood services researchers has been identified as key in developing a sustainable programme of generation local evidence to support sound decision making. There are a number of research training programmes that have been instituted targeted at blood services in Africa. The article shares programme experiences of building research capacities for blood services in Africa. Methodology: The Francophone Africa Transfusion Medicine Research Training network, the NIH REDS-III and NIH Fogarty South Africa programmes and T-REC (Building research capacities in Africa) have been the key research capacity programmes targeting blood services in Africa over the last decade. Data were drawn from research outputs, publications and end of programme reports. The focus was to understand their experiences on the implementation of the capacity building programmes highlighting the success, challenges and the main research outputs from their initiatives. Results: The Francophone research network achievements included more than 135 trainees and in excess of 30 publications. The NIH REDS study the achievements included more than 12 research publications with South Africa junior investigators as lead authors. The NIH Fogarty program currently includes 56 short course trainees, 5 Masters and 6 PhD candidates. The four year (2011-2015, funding period) T-REC research capacity has as of 2020 managed to produce 4 PhDs, 42 in-service Diploma in Project Design and Management (DPDM), and supported bursaries for 60 Masters/undergraduate research. The main common challenges in the running of the research programmes include shortages of in-country mentoring and identified needs in high quality research grants writing. Discussion and conclusion: It has been noted that the key achievements for the blood services research capacity building include a mix of short courses, medium-term (epidemiology & biostats) and MS/PhD degree training. Also, having a train the trainers to develop in-country mentors has been instrumental. Overall, the key recommendations for blood services research capacity building include the need for research collaborations with high-income countries which can jump-start research. For a sustainable research programme, eventually there is need for in-country grant-writing capacity building

Epidemiology of Human Parvovirus 4 Infection in Sub-Saharan Africa

Human parvovirus 4 infections are primarily associated with parenteral exposure in western countries. By ELISA, we demonstrate frequent seropositivity for antibody to parvovirus 4 viral protein 2 among adult populations throughout sub-Saharan Africa (Burkina Faso, 37%; Cameroon, 25%; Democratic Republic of the Congo, 35%; South Africa, 20%), which implies existence of alternative transmission routes

Évaluation du suivi pré- et post-transfusionnel des patients au C.H.U. D'Amiens (intérêt de la vaccination contre le virus de l'hépatite B pour les patients polytransfusés)

La transfusion sanguine est avant tout une discipline médicale dont la particularité est de traiter " l'homme par l'homme " : un sujet sain et volontaire, le donneur, constitue la source du traitement d'un malade, le receveur. Après le drame du sang contaminé par le virus du syndrome d'immunodéficience acquise (SIDA), de nombreuses modifications de la gestion du risque transfusionnel ont été opérées. Plusieurs mesures ont contribué à un renforcement de la qualité et de la sécurité de la pratique transfusionnelle, notamment concernant le risque lié aux trois virus principaux : les virus des hépatites B (VHB), C (VHC) et le virus de l'immunodéficience humaine (VIH). Toutefois, le risque de transmission de ces trois virus majeurs devenu certes très faible, persistait. De ce fait, en 1996, une circulaire a recommandé de proposer aux receveurs de produits sanguins labiles un dépistage des anticorps anti-VIH et anti-VHC immédiatement avant la transfusion, puis trois mois après. Nous avons réalisé une évaluation de ces recommandations pour l'ensemble des patients transfusés au C.H.U d'Amiens sur une période d'étude de trois mois. En pré-transfusionnel, 64 % des receveurs ont eu un dépistage pré-transfusionnel et 33 % un dépistage post-transfusionnel. Seuls 15 % des transfusés ont eu à la fois des tests pré- et post-transfusionnels et 18 % n'ont eu aucun suivi. Nous avons ainsi démontré que les recommandations telles qu'elles sont définies actuellement sont peu suivies. De plus, nous nous sommes intéressés aux patients polytransfusés chroniques. En effet, ils constituent la population la plus menacée par le risque résiduel viral transfusionnel dont le principal demeure celui lié au VHB. Or, malgré l'existence d'une prévention vaccinale à l'efficacité prouvée, seuls 24 % avaient lors de l'étude un statut sérologique de vacciné. Une réflexion sur le bien-fondé de ces recommandations devrait être engagée afin qu'elles soient plus adaptées à la pratique transfusionnelle actuelle. En effet, une systématisation de ces dépistages pré- et post-transfusionnels, seul garant d'un impact significatif dans la population des transfusés compte tenu du risque résiduel actuel très faible, serait une mesure dont le rapport coût-efficacité n'en fait pas une priorité de santé publique.AMIENS-BU Santé (800212102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Hepatitis B Virus Blood Screening: Need for Reappraisal of Blood Safety Measures?

Over the past decades, the risk of HBV transfusion–transmission has been steadily reduced through the recruitment of volunteer donors, the selection of donors based on risk-behavior evaluation, the development of increasingly more sensitive hepatitis B antigen (HBsAg) assays, the use of hepatitis B core antibody (anti-HBc) screening in some low-endemic countries, and the recent implementation of HBV nucleic acid testing (NAT). Despite this accumulation of blood safety measures, the desirable zero risk goal has yet to be achieved. The residual risk of HBV transfusion–transmission appears associated with the preseroconversion window period and occult HBV infection characterized by the absence of detectable HBsAg and extremely low levels of HBV DNA. Infected donations tested false-negative with serology and/or NAT still persist and derived blood components were shown to transmit the virus, although rarely. Questions regarding the apparent redundancy of some safety measures prompted debates on how to reduce the cost of HBV blood screening. In particular, accumulating data strongly suggests that HBsAg testing may add little, if any HBV risk reduction value when HBV NAT and anti-HBc screening also apply. Absence or minimal acceptable infectious risk needs to be assessed before considering discontinuing HBsAg. Nevertheless, HBsAg remains essential in high-endemic settings where anti-HBc testing cannot be implemented without compromising blood availability. HBV screening strategy should be decided according to local epidemiology, estimate of the infectious risk, and resources

Contribution à la sécurité transfusionnelle par une veille épidémiologique de la diversité et de l'émergence virales

Ce travail comprend deux volets : l appréciation du risque transfusionnel viral et son évolution ; la maîtrise de ce risque au travers d une veille scientifique et technique. Le risque résiduel est établi selon un modèle mathématique utilisant des données observées sur la population des donneurs de sang (DS) français et sur l histoire naturelle des infections concernées. La maîtrise du risque s appuie sur (i) la surveillance de la diversité virale chez les DS, afin de prévenir des défaillances du dépistage, (ii) la vigilance sur les outils de dépistage (validation des techniques existantes ou nouvelles) et l évaluation de la stratégie globale du dépistage, (iii) la veille sur les risques émergents. Le risque lié aux virus majeurs a atteint son niveau le plus bas grâce à l action conjuguée de nombreuses mesures préventives. Son évolution montrant une tendance à la stabilisation, on peut s interroger sur les actions spécifiques qui pourraient encore le réduire.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Presence of Human Hepegivirus-1 in a Cohort of People Who Inject Drugs

International audienceNo abstract availabl

Performance of the Cobas AmpliPrep/Cobas TaqMan Real-Time PCR Assay for Hepatitis B Virus DNA Quantification▿

Hepatitis B virus (HBV) DNA quantification is used to establish the prognosis of chronic HBV-related liver disease, to identify those patients who need to be treated, and to monitor the virologic response and resistance to antiviral therapies. Real-time PCR-based assays are gradually replacing other technologies for routine quantification of HBV DNA in clinical practice. The goal of this study was to evaluate the intrinsic characteristics and clinical performance of the real-time PCR Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) platform for HBV DNA quantification. Specificity was satisfactory (95% confidence interval, 98.1 to 100%). Intra-assay coefficients of variation ranged from 0.22% to 2.68%, and interassay coefficients of variation ranged from 1.31% to 4.13%. Quantification was linear over the full dynamic range of quantification of the assay (1.7 to 8.0 log10 IU/ml) and was not affected by dilution. The assay was accurate regardless of the HBV genotype. Samples containing HBV DNA levels above 4.5 log10 IU/ml were slightly underestimated relative to another accurate assay based on branched-DNA technology, but this is unlikely to have noteworthy clinical implications. Thus, the CAP/CTM HBV DNA assay is sensitive, specific, and reproducible, and it accurately quantifies HBV DNA levels in patients chronically infected by HBV genotypes A to F. Samples with HBV DNA concentrations above the upper limit of quantification need to be diluted and then retested. Broad use of fully automated real-time PCR assays should improve the management of patients with chronic HBV infection

Performance of Version 2.0 of the Cobas AmpliPrep/Cobas TaqMan Real-Time PCR Assay for Hepatitis B Virus DNA Quantification ▿

The detection and quantification of hepatitis B virus (HBV) DNA are essential for the diagnosis and treatment of chronic HBV infection. The use of real-time PCR assays for HBV DNA quantification is strongly recommended. The goal of this study was to evaluate the intrinsic characteristics and clinical performance of version 2.0 (v2.0) of the Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) assay, a fully automated platform for HBV DNA quantification in serum or in plasma with a claimed lower limit of detection of 20 IU/ml and a claimed upper limit of quantification of 1.7 × 108 IU/ml. The specificity of the assay was 99% (95% confidence interval, 94.7 to 100%). Intra-assay and interassay coefficients of variation ranged from 0.21% to 2.67% and from 0.65% to 2.25%, respectively. The calibration of the assay was found to be satisfactory. Study of blood specimens from patients infected with HBV genotypes A to F showed good correspondence between HBV DNA levels measured by the CAP/CTM v2.0 assay, version 1.0 of the same assay, and the third-generation “branched DNA” assay. The CAP/CTM v2.0 assay quantified HBV DNA levels in serum or plasma from the same patients equally. In conclusion, the new version of the CAP/CTM assay is sensitive, specific, and reproducible. It accurately quantifies HBV DNA levels in patients chronically infected with HBV genotypes A to F. Improvements made to ensure equal quantification of HBV DNA in serum and plasma have been successful. Overall, the CAP/CTM assay, version 2.0, is well suited to monitoring clinical HBV DNA levels according to current clinical practice guidelines