Performance evaluation of the Access HBsAg and Access HBsAg confirmatory assays on the DxI 9000 Access Immunoassay Analyzer.

Introduction: This study evaluated the clinical and analytical performances of the Access HBsAg and the Access HBsAg Confirmatory assays on the DxI 9000 Access Immunoassay Analyzer (Beckman Coulter, Inc.). Materials and methods: Diagnostic specificity and sensitivity of the Access HBsAg and Access HBsAg Confirmatory assays were evaluated by comparing the Access assays to the final HBsAg sample status determined using the Architect, PRISM, or Elecsys HBsAg assays, along with Architect or PRISM HBsAg Confirmatory assays. Imprecision, sensitivity on seroconversion panels, analytical sensitivity on WHO, and recognition of HBV variants were also evaluated. Results: A total of 7534 samples were included in the analysis (6047 blood donors, 1032 hospitalized patients, 455 positive patients' samples). Access HBsAg assay sensitivity and specificity were at 100.00% (99.19-100.0) and 99.92% (99.82-99.97), respectively. Sensitivity of Access HBsAg Confirmatory assay was 100.00% (99.21-100.0) on the 464 HBsAg positive samples. The use of a high positive algorithm for the Access HBsAg assay, wherein samples with S/CO ≥ 100.00 were considered positive without requiring repeat or confirmatory testing, was successfully evaluated with all 450 specimens with S/CO greater than 100.00 (sensitivity 100.00%; 99.19-100.0). Access HBsAg assay demonstrated good analytical performance, equivalent recognition of seroconversion panels compared to Architect assay, and an analytical sensitivity between 0.022 and 0.025 IU/mL. All HBV genotypes, subtypes and mutants were well detected without analytical sensitivity loss. Conclusion: Access HBsAg and Access HBsAg Confirmatory assays demonstrated robust performances. They provide low samples volume requirements and a simplified process, no systematic retesting for high positive samples.

Evaluation of the ELITechGroup solution for plasma HIV-1 RNA quantification.

In the last few years, many manufacturers have developed new kits for plasma HIV-1 RNA quantification. Recently, a solution consisting of the ELITe InGenius® instrument and the HIV1 ELITe MGB®kit has been commercialized worldwide. Our aim was to compare its clinical performance with the Aptima® HIV-1 Quant Dx kit by Hologic, on a panel of HIV-1 group M circulating variants, representative of viral load levels found during the pre- and post-treatment follow-up of patients. The linearity was evaluated on the AcroMetrix® HIV-1 Panel. Clinical specificity was evaluated on 100 plasma samples negative for HIV; and clinical sensitivity and sequential follow-up were evaluated on 166 HIV-1 positive plasma samples from 126 patients. The linearity data showed a difference obtained for each point of less than 0.2 Log cp/mL. No amplification was found for the 100 HIV negative clinical specimens. The overall agreement between the two kits was 83.7 %; the differences corresponded to a slightly higher detection for the Aptima kit (with more samples detected below the lower limit of quantification). A Bland & Altman analysis of the quantifiable samples showed a mean difference of -0.05 Log and Spearman's coefficient was 0.975. Only six samples presented discrepancies (above 0.5 Log), but these differences were overall similar between the two kits. Our study has shown that the HIV1 ELITe MGB® Kit can be successfully used for the monitoring of patients infected with various epidemic HIV-1 strains, and for the precise quantification of the viral load.

In vitro replicative potential of an HIV-1/MO intergroup recombinant virus compared to HIV-1/M and HIV-1/O parental viruses.

Genetic recombination is one of the major evolution processes of HIV-1. Despite their great genetic divergence, HIV-1 groups M and O can generate HIV-1/MO intergroup recombinants. The current description of 20 HIV-1/MO unique recombinant forms suggests a possible benefit of the recombination. The aim of this work was to study in vitro the replicative potential of HIV-1/MO recombinant forms. This analysis was based on a simple recombination pattern, [Ogag/pol-Menv], harboring a breakpoint in Vpr. A chimeric infectious molecular clone, pOM-TB-2016 was synthesized from HIV-1/M subtype B and HIV-1/O subgroup T and recombinant viruses were obtained by transfection/co-culture. To compare the replicative potential of these viruses, two markers were monitored in culture supernatants: Reverse Transcriptase (RT) activity and P24 antigen concentration. The results showed a superiority of the group M parental virus compared to group O for both markers. In contrast, for the recombinant virus, RT activity data did not overlap with the concentration of P24 antigen, suggesting a hybrid behavior of the recombinant, in terms of enzyme activity and P24 production. These results highlighted many hypotheses about the impact of recombination on replicative potential and demonstrated again the significant plasticity of HIV genomes and their infinite possibility of evolution.

Knowledge, attitudes and practices of French university students towards COVID-19 prevention-are health students better?

During the COVID-19 outbreak in 2020, public health measures (PHM) were implemented to prevent the spread of SARS-CoV-2. At university, we wondered whether health students would be more likely to comply with these safety measures against infectious disease transmission compared to other students. Thus, we collected 1 426 university students' responses to an online anonymous survey to describe their knowledge, attitudes and practices (KAP) of COVID-19 prevention measures and to compare the opinions and practices of health students and science students at the same university of Rouen Normandy (France). A higher proportion of science students (84.6%) compared to health students (73.9%) reported knowledge of the university's COVID-19 protocol, p<0.001. However, the health students compared to science students reported a higher compliance with PHM at home (91.4% vs 88.0%) and at university (94.1% vs 91.1%). In a multiple regression analysis, after adjustment for age, sex and university department, factors associated with higher compliance with PHM were knowledge of the university's COVID-19 protocol and a high perceived efficacy of PHM. A SARS-CoV-2 PCR result was not predictive of compliance with PHM. The results of this online survey in French students show a high level of knowledge and practices of COVID-19 prevention Although their performances could still be improved by training, the good results of health students regarding knowledge, attitudes and practices are encouraging as these students could be an added backup force to fight against viral pandemics.

Are Confirmatory Assays Reliable for HIV-1/HIV-2 Infection Differentiation? A Multicenter Study.

Immunoblots remain the gold standard for HIV-1/HIV-2 infection confirmation. However, their ability to differentiate HIV-1 from HIV-2 infection on an antigenically diversified HIV-1 and HIV-2 panel remain uncommon. We performed a multicenter study on 116 serum samples accounting for most of the diversity of HIV-1 (9 different subtypes in group M, 17 circulating recombinant forms (CRFs), and 3 group O) and HIV-2 (groups A and B), evaluating seven confirmatory assays (six commercially available assays and one in-house assay) with genotyping as the reference. The assays were INNO-LIA HIV I/II score, HIV-2 blot 1.2, HIV blot 2.2, New Lav blot I and II, Geenius, and an in-house serotyping enzyme-linked immunosorbent assay (ELISA). Among the HIV-1 samples, INNO-LIA, HIV blot 2.2, New Lav blot I, Geenius, and serotyping had comparable high sensitivities, from 98% to 100%, whereas HIV-2 blot 1.2 and New Lav blot II had high rates of "undetermined" results (85% and 95%, respectively). HIV-2 blot 1.2 and New Lav blot II misclassified 7% and 5% of HIV-1 samples as HIV-2, respectively, and HIV-2 blot 1.2 had an 8% false-negative rate. Among the HIV-2 samples, INNO-LIA, New Lav blot II, HIV-2 blot 1.2, and serotyping had high sensitivities, from 96% to 100%. HIV blot 2.2 misclassified 17% of HIV-2 samples as HIV-1/HIV-2 dual infections. New Lav blot I misclassified 19% of HIV-2 samples as HIV-1 with a high (81%) undetermined rate, and Geenius misclassified 2% as HIV-1 and 7% as untypeable HIV positive. For HIV-1/HIV-2 dual infection, the results were less sensitive, with at most 87.5% for INNO-LIA and Geenius and 75% for HIV blot 2.2 and serotyping. Overall, confirmatory assays remain useful for most cases, with the exception of HIV-1/HIV-2 dual-infection suspicion.

Evaluation of Analytical and Clinical Performance and Usefulness in a Real-Life Hospital Setting of Two in-House Real-Time RT-PCR Assays to Track SARS-CoV-2 Variants of Concern.

Since the end of 2020, multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) have emerged and spread worldwide. Tracking their evolution has been a challenge due to the huge number of positive samples and limited capacities of whole-genome sequencing. Two in-house variant-screening RT-PCR assays were successively designed in our laboratory in order to detect specific known mutations in the spike region and to rapidly detect successively emerging VOCs. The first one (RT-PCR#1) targeted the 69-70 deletion and the N501Y substitution simultaneously, whereas the second one (RT-PCR#2) targeted the E484K, E484Q, and L452R substitutions simultaneously. To evaluate the analytical performance of these two RT-PCRs, 90 negative and 30 positive thawed nasopharyngeal swabs were retrospectively analyzed, and no discordant results were observed. Concerning the sensitivity, for RT-PCR#1, serial dilutions of the WHO international standard SARS-CoV-2 RNA, corresponding to the genome of an Alpha variant, were all detected up to 500 IU/mL. For RT-PCR#2, dilutions of a sample harboring the E484K substitution and of a sample harboring the L452R and E484Q substitutions were all detected up to 1000 IU/mL and 2000 IU/mL, respectively. To evaluate the performance in a real-life hospital setting, 1308 and 915 profiles of mutations, obtained with RT-PCR#1 and RT-PCR#2, respectively, were prospectively compared to next-generation sequencing (NGS) data. The two RT-PCR assays showed an excellent concordance with the NGS data, with 99.8% for RT-PCR#1 and 99.2% for RT-PCR#2. Finally, for each mutation targeted, the clinical sensitivity, the clinical specificity and the positive and negative predictive values showed excellent clinical performance. Since the beginning of the SARS-CoV-2 pandemic, the emergence of variants-impacting the disease's severity and the efficacy of vaccines and therapies-has forced medical analysis laboratories to constantly adapt to the strong demand for screening them. Our data showed that in-house RT-PCRs are useful and adaptable tools for monitoring such rapid evolution and spread of SARS-CoV-2 VOCs.

HIV-1 Non-Group M Strains and ART.

To eliminate HIV infection, there are several elements to take into account to limit transmission and break viral replication, such as epidemiological, preventive or therapeutic management. The UNAIDS goals of screening, treatment and efficacy should allow for this elimination if properly followed. For some infections, the difficulty is linked to the strong genetic divergence of the viruses, which can impact the virological and therapeutic management of patients. To completely eliminate HIV by 2030, we must therefore also be able to act on these atypical variants (HIV-1 non-group M) which are distinct from the group M pandemic viruses. While this diversity has had an impact on the efficacy of antiretroviral treatment in the past, recent data show that there is real hope of eliminating these forms, while maintaining vigilance and constant surveillance, so as not to allow more divergent and resistant forms to emerge. The aim of this work is therefore to share an update on the current knowledge on epidemiology, diagnosis and antiretroviral agent efficacy of HIV-1 non-M variants.

Molecular confirmation of HIV-1 and HIV-2 coinfections among initially serologically dually-reactive samples from patients living in West Africa.

OBJECTIVES: This study aimed to confirm the co-infection with HIV-1 and HIV-2, among West African patients using in-house HIV type/group enzyme-immuno assays and molecular diagnosis. DESIGN: A cross-sectional survey was conducted from April 2016 to October 2017 in the biggest HIV clinics of Côte d'Ivoire and Burkina Faso. METHOD: A first serological confirmation was done in the referral laboratory using an in-house, indirect immuno-enzymatic essay allowing the qualitative detection of both HIV-1 and HIV-2 antibodies. In order to separately detect anti-HIV-1 and anti-HIV-2 antibodies, a type/group specific enzyme-immuno assay (HIV-GSEIA) was used. To confirm the co-infections, HIV-1 and HIV-2 DNA-qualitative PCR assays were performed. RESULTS: A total of 91 patients were enrolled in the study and provided blood sample for HIV type confirmatory testing including 13 (14.3%) HIV-2 mono-reactive and 78 (85.7%) HIV-1/HIV-2 dually-reactive based on the HIV testing National Algorithms. The first serological ELISA confirmatory test performed showed that 80 (78.9%) of the 91 participants were dually-reactive. The HIV-GSEIA performed on these 80 serum samples retrieve one 61 HIV-1/HIV-2 dually-reactive samples. HIV-1 and HIV-2 DNA PCR were performed on 54 of the 61 HIV-1/HIV-2 dually-reactive samples and 46 out of 61 (75.4%) samples were found HIV-1/HIV-2 coinfected. CONCLUSION: The contribution of type/group specific enzyme-immuno assay to accurately identify HIV-1/HIV-2 coinfections remain suboptimal, emphasizing the need for molecular diagnosis platforms in West Africa, to avail HIV DNA PCR test for the confirmation of HIV-1/HIV-2 co-infections.

Evidence of Transmission and Circulation of Deltacron XD Recombinant Severe Acute Respiratory Syndrome Coronavirus 2 in Northwest France.

In February 2022, samples collected in northwest France showed discordant molecular results. After virological and epidemiological investigations, 17 cases of Deltacron XD recombinant severe acute respiratory syndrome coronavirus 2 were confirmed by sequencing or suspected due to epidemiological links, showing evidence of an extended transmission event and circulation of this form, with low clinical severity.

Investigation of outbreak cases infected with the SARS-CoV-2 B.1.640 variant in a fully vaccinated elderly population, Normandy, France, November to December 2021.

Three confirmed infections with the SARS-CoV-2 B.1.640 variant under monitoring were reported in Normandy, north-western France in late November 2021. Investigations led to the identification of two events linked to the same cluster. A total of 75 confirmed and probable B.1.640 cases were reported. All had completed the primary vaccination series. Sixty-two cases were older than 65 years. Fifty-six cases had symptoms and four were hospitalised. This investigation provides preliminary results concerning a variant with limited information currently available.

Performance Analysis of Three Commercial Kits Designed for RNA Quantification of HIV-1 Group O Variants.

BACKGROUND: The genetic divergence of HIV-1 group O is high relative to pandemic group M, which could impact detection and quantification of plasma RNA. Recent commercial kits for RNA quantification seem to show good performances in HIV-1/O, but discrepancies are still observed. Here, we compare the performances of 3 commercial assays for the RNA quantification of HIV-1/O. METHODS: We studied the RNA quantification of 117 clinical samples using Abbott RealTime HIV-1, Cepheid Xpert HIV-1 Viral Load, or Roche Cobas TaqMan HIV-1 v2. First, we conducted a qualitative description, and second, we focused on a quantitative analysis of the results above 40 cp/mL. The degree of agreement between methods and the strength of the correlation of viral load determination were estimated using Bland-Altman plot and Passing-Bablok regression with the Spearman coefficient, respectively. RESULTS: Our 2-by-2 analysis showed that the Abbott and Cepheid assays were very close in terms of correlation and dispersion of points, whereas Roche presented higher values in the highest range of quantification (>5 log10). The Cepheid assay combined better correlation with the consensus value and a lower dispersion of values, leading to an overall better performance of quantification. The quantification was still impacted by intragroup genetic diversity with, here, 1 strain (YBF26). CONCLUSIONS: Using a new approach to compare the performances of RNA quantification between more than 2 techniques, we demonstrated that Cepheid could be the most suitable assay for HIV-1/O quantification, although the results from all assays remained strain dependent.

HIV-1 non-group M phenotypic susceptibility in vitro to bictegravir and cabotegravir.

OBJECTIVES: HIV-1 group O (HIV-1/O) is one of the four HIV-1 groups and is endemic in Cameroon, representing 1% of HIV-1 infections in the population. Around 50% of the strains of this group naturally show a mutation (Y181C) providing them with resistance to NNRTIs and making therapeutic management more difficult. Today, the WHO recommends the use of integrase strand transfer inhibitors (INSTIs) as first-line treatment. Bictegravir and cabotegravir are the two most recent INSTIs. Because of the genetic polymorphism of HIV-1/O, studies are required to evaluate their phenotypic susceptibility to these two drugs. PATIENTS AND METHODS: We performed a phenotypic study on a large panel including 41 HIV-1/O clinical isolates and other rare non-group M HIV-1 (2 HIV-1/N and 1 HIV-1/P) to evaluate in vitro susceptibility to bictegravir and cabotegravir. RESULTS: The results showed an overall susceptibility of non-group M strains to the two drugs compared with HIV-1 group M. There was no difference between the mean (min-max) IC50 of HIV-1/M [1.86 (0.93-4.12) and 5.24 (1.76-12.41) nM for bictegravir and cabotegravir, respectively] and HIV-1/non-M [2.17 (0.03-9.47) and 4.88 (0.02-15.64) nM for bictegravir and cabotegravir, respectively]. However, we found a significant difference between IC50 values for bictegravir and cabotegravir in the whole panel (P value < 0.001). CONCLUSIONS: This study has shown encouraging results regarding the clinical use of these drugs in HIV-1/non-M-infected patients, which will need to be confirmed with clinical data.

Antibody and T Cell Response to SARS-CoV-2 Messenger RNA BNT162b2 Vaccine in Kidney Transplant Recipients and Hemodialysis Patients.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with a high rate of mortality in patients with ESKD, and vaccination is hoped to prevent infection. METHODS: Between January 18 and February 24, 2021, 225 kidney transplant recipients (KTRs) and 45 patients on hemodialysis (HDPs) received two injections of mRNA BNT162b2 vaccine. The postvaccinal humoral and cellular response was explored in the first 45 KTRs and ten HDPs. RESULTS: After the second dose, eight HDPs (88.9%) and eight KTRs (17.8%) developed antispike SARS-CoV-2 antibodies (P<0.001). Median titers of antibodies in responders were 1052 AU/ml (IQR, 515-2689) in HDPs and 671 AU/ml (IQR, 172-1523) in KTRs (P=0.40). Nine HDPs (100%) and 26 KTRs (57.8%) showed a specific T cell response (P=0.06) after the second injection. In responders, median numbers of spike-reactive T cells were 305 SFCs per 106 CD3+ T cells (IQR, 95-947) in HDPs and 212 SFCs per 106 CD3+ T cells (IQR, 61-330) in KTRs (P=0.40). In KTRs, the immune response to BNT162b2 seemed influenced by the immunosuppressive regimen, particularly tacrolimus or belatacept. CONCLUSION: Immunization with BNT162b2 seems more efficient in HDPs, indicating that vaccination should be highly recommended in these patients awaiting a transplant. However, the current vaccinal strategy for KTRs may not provide effective protection against COVID-19 and will likely need to be improved.

Modeling SARS-CoV-2 viral kinetics and association with mortality in hospitalized patients from the French COVID cohort.

The characterization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral kinetics in hospitalized patients and its association with mortality is unknown. We analyzed death and nasopharyngeal viral kinetics in 655 hospitalized patients from the prospective French COVID cohort. The model predicted a median peak viral load that coincided with symptom onset. Patients with age ≥65 y had a smaller loss rate of infected cells, leading to a delayed median time to viral clearance occurring 16 d after symptom onset as compared to 13 d in younger patients (P < 10-4). In multivariate analysis, the risk factors associated with mortality were age ≥65 y, male gender, and presence of chronic pulmonary disease (hazard ratio [HR] > 2.0). Using a joint model, viral dynamics after hospital admission was an independent predictor of mortality (HR = 1.31, P < 10-3). Finally, we used our model to simulate the effects of effective pharmacological interventions on time to viral clearance and mortality. A treatment able to reduce viral production by 90% upon hospital admission would shorten the time to viral clearance by 2.0 and 2.9 d in patients of age <65 y and ≥65 y, respectively. Assuming that the association between viral dynamics and mortality would remain similar to that observed in our population, this could translate into a reduction of mortality from 19 to 14% in patients of age ≥65 y with risk factors. Our results show that viral dynamics is associated with mortality in hospitalized patients. Strategies aiming to reduce viral load could have an effect on mortality rate in this population.