Analytical performances of a point-of-care loop-mediated isothermal amplification assay to detect Group B Streptococcus in intrapartum pregnant women living in the Democratic Republic of the Congo.

OBJECTIVES: Group B Streptococcus (GBS) is the leading infectious cause of stillbirth and neonatal morbidity and mortality in sub-Saharan Africa. METHODS: Vaginal and rectovaginal swab samples were obtained from 274 intrapartum pregnant women in the Democratic Republic of the Congo to be analyzed for GBS DNA detection in parallel by the point-of-care BIOSYNEX AMPLIFLASH® GBS assay (Biosynex SA, Illkirch-Graffenstaden, France) and by reference quantitative polymerase chain reaction (qPCR). RESULTS: Rectovaginal swabbing, nearly two-fold more positive for GBS than vaginal swabbing alone, showed a high prevalence of GBS DNA positivity in 20.1% of eligible intrapartum pregnant women. In the event of significant bacterial carriage (i.e., cycle threshold ≤33 by reference qPCR), the AMPLIFLASH® GBS assay with rectovaginal swabbing showed high sensitivity (98.1%) and specificity (100.0%) for GBS DNA detection, with excellent concordance, reliability, and accuracy with the reference qPCR, and positive predictive values and negative predictive values above 99.0%. CONCLUSIONS: The study demonstrates a high rate of female rectogenital GBS colonization in pregnant Congolese women. The AMPLIFLASH® GBS assay harbored excellent analytical performances in the field, which makes it suitable to be used as point-of-care molecular assay in various hospital and non-hospital settings where rapid diagnosis of GBS is necessary.

Rotavirus and adenovirus infections in children with acute gastroenteritis after introducing the Rotasiil® vaccine in Kisangani, Democratic Republic of the Congo.

BACKGROUND: Although rotavirus vaccination has reduced the global burden of the virus, morbidity and mortality from rotavirus infection remain high in Sub-Saharan Africa. This study aimed to determine the prevalence of rotavirus and adenovirus infections in children under five years with acute gastroenteritis and to identify factors associated with rotavirus infection after the introduction of the Rotasiil® vaccine in 2019 in Kisangani, Democratic Republic of the Congo (DRC). METHODS: This study consisted of a cross-sectional hospital-based survey conducted from May 2022 to April 2023 in four health facilities in Kisangani, using a fecal-based test (rapid antigenic immuno-chromatographic diagnostic test, BYOSYNEX adenovirus/rotavirus BSS, Biosynex SA, Illkirch-Graffenstaden, France) of rotavirus and adenovirus infections among children under five years of age with acute gastroenteritis. RESULTS: A total of 320 children under five years of age with acute gastroenteritis were included. The prevalence of rotavirus infection was 34.4%, that of adenovirus was 6.3%, and that of both rotavirus and adenovirus coinfection was 1.3%. The prevalence of rotavirus was significantly higher in unvaccinated children than in vaccinated children (55.4% versus 23.1%; P < 0.001). This difference was observed only in children who received all three vaccine doses. Multivariate logistic regression analysis shows that the rate of rotavirus infection was significantly reduced in vaccinated children (adjusted OR: 0.31 [95% confidence intervals (CI): 0.19-0.56]; P < 0.001) and those whose mothers had an average (adjusted OR: 0.51 [95% CI: 0.25-0.91]; P = 0.018) or high level (adjusted OR: 0.34 [95% CI: 0.20-0.64]; P < 0.001) of knowledge about the rotavirus vaccine. CONCLUSIONS: The prevalence of rotavirus infection remains high in Kisangani despite vaccination. However, the prevalence of adenovirus infections was low in our series. Complete vaccination with three doses and mothers' average and high level of knowledge about the rotavirus vaccine significantly reduces the rate of rotavirus infection. It is, therefore, essential to strengthen the mothers' health education, continue with the Rotasiil® vaccine, and ensure epidemiological surveillance of rotavirus infection.

Genetic diversity of HPV35 in Chad and the Central African Republic, two landlocked countries of Central Africa: A cross-sectional study.

Human Papillomavirus (HPV)-35 accounts for up 10% of cervical cancers in Sub-Saharan Africa. We herein assessed the genetic diversity of HPV35 in HIV-negative women from Chad (identified as #CHAD) and HIV-infected men having sex with men (MSM) in the Central African Republic (CAR), identified as #CAR. Ten HPV35 DNA from self-collected genital secretions (n = 5) and anal margin samples (n = 5) obtained from women and MSM, respectively, were sequenced using the ABI PRISM® BigDye Sequencing technology. All but one HPV35 strains belonged to the A2 sublineage, and only #CAR5 belonged to A1. HPV35 from #CAR had higher L1 variability compared to #CHAD (mean number of mutations: 16 versus 6). L1 of #CAR5 showed a significant variability (2.29%), suggesting a possible intra-type divergence from HPV35H. Three (BC, DE, and EF) out of the 5 capsid loops domains remained totally conserved, while FG- and HI- loops of #CAR exhibited amino acid variations. #CAR5 also showed the highest LCR variability with a 16bp insertion at binding sites of the YY1. HPV35 from #CHAD exhibited the highest variability in E2 gene (P<0.05). E6 and E7 oncoproteins remained well conserved. There is a relative maintenance of a well conserved HPV35 A2 sublineage within heterosexual women in Chad and MSM with HIV in the Central African Republic.

Human papillomavirus genotype distribution by cytological status and associated risk factors in the general population of Congolese women living in urban and rural areas: Implications for cervical cancer prevention.

INTRODUCTION: Cervical cancer related to high risk-human papillomavirus (HR-HPV) is the second female cancer in the Republic of Congo (Congo). We herein evaluated the molecular epidemiology of cervical HPV infection and associated risk factors in Congolese women living in urban (Brazzaville) and rural (Plateaux department) settings. PATIENTS AND METHODS: A population-based, cross-sectional survey was conducted to collect demographic and behavioral data among Congolese women, and to obtain endocervical swab samples for HPV DNA molecular detection (Anyplex II HPV28, Seegene, Seoul, South Korea). RESULTS: A total of 284 women (mean age: 37.8 years; HIV-1-positivity: 18.6%) were included. The prevalence of HPV DNA cervical shedding was 64.4% [HR-HPV: 80.9%, mainly HPV-16 (15.8%), and HPV-35 and HPV-52 (15.3%); multiple HPV infections: 60.6%; 9-valent HPV Gardasil-9® vaccine genotypes: 42.6%]. 91.6% and 100% of low-grade squamous intraepithelial neoplasia (LSIL) and cervical cancer, respectively, showed HR-HPV. HR-HPV prevalence was higher among students (aOR: 7.9) and HIV-infected women (aOR: 3.1) in Brazzaville, and among women aged between 21-30 years (aOR: 7.2) and HIV-infected women (aOR: 5.1) in the Plateaux department. CONCLUSION: Cervical HR-HPV infection is particularly frequent in young or HIV-infected Congolese women. Prophylactic HPV vaccination combined with primary molecular screening of HR-HPV infection in this country should be extended.

TRANSLACOL project: Nodal human papillomavirus tumoral DNA detection by ddPCR for survival prediction in early cervical cancer patients without pelvic lymph node invasion.

INTRODUCTION: In early cervical cancer (EEC), 10 to 15% of patients without nodal metastasis (N-) will suffer from recurrences with further similar survival as N+ patients. However, no clinical, imaging or pathological risk-factor is today available to identify them. In the present study, we hypothesized that the N- histologically characterized patients who present a poor prognosis could be patients for whom metastasis are missed by classical procedure. Therefore, we propose to research HPV tumoral DNA (HPVtDNA) in pelvic Sentinel Lymph Nodes (SLN) biopsy using ultrasensitive droplet-based digital PCR (ddPCR) to detect eventual occult metastasis. MATERIALS AND METHODS: Sixty HPV16, HPV18 or HPV33 positive EEC N- patients with available SLN were included. In SLN, HPV16 E6, HPV18 E7 and HPV33 E6 gene were respectively detected using ultrasensitive ddPCR technology. Survival data were analysed using Kaplan-Meier-curves and log-rank-test to compare progression-free survival (PFS) and disease-specific survival (DSS) in two groups according to their HPVtDNA status in SLN. RESULTS: More than half (51.7%) of the patients finally showed HPVtDNA positivity in SLN initially diagnosed as negative by histology. Two patients with negative HPVtDNA SLN and 6 with positive HPVtDNA SLN group presented recurrence. Finally, all of the 4 deaths listed in our study occurred in the positive HPVtDNA SLN group. CONCLUSION: These observations hint that the use of ultrasensitive ddPCR to detect HPVtDNA in SLN could allow the identification of two subgroups of histologically N- patients that may have different prognosis and outcome. To our knowledge, our study is the first one to evaluate the detection of HPVtDNA in SLN in early cervical cancer using ddPCR highlighting its interest as a complementary tool for N- specific early cervical cancer diagnosis.

HPV Molecular Genotyping as a Differential Diagnosis Tool in Cervical Cancer Metastasis.

BACKGROUND: Differentiating metastatic cervical cancer from another primary tumor can be difficult in patients with a history of cervical cancer and a distant lesion. The use of routine HPV molecular detection and genotyping tests could help in these cases. The objective of this study was to identify if an easy-to-use HPV molecular genotyping assay would allow differentiating between HPV tumor metastasis and a new independent primary non-HPV-induced tumor. MATERIALS AND METHODS: Between 2010 and 2020, we identified patients with a primary cervical carcinoma who also had another secondary lesion. This identification included a clinical and histologic differential diagnosis of metastatic cervical cancer versus a new primary cancer or metastatic cancer from another site. We used a routine multiplex real-time PCR (rt-PCR) AnyplexTM II HPV28 (Seegene, Seoul, Republic of Korea) to detect the high-risk (HR)-HPV genome in the distant lesions in these patients. RESULTS: Eight cases of cervical cancer with a new secondary lesion were identified. In seven, HR-HPV DNA was detected in the biopsy of the distant lesion, which confirmed the diagnosis of cervical cancer metastasis. In the remaining case, no HPV was detected in the secondary lung biopsy, confirming the diagnosis of new primary lung cancer. CONCLUSION: Our results pave the way for HPV molecular genotyping use in cases of newly diagnosed distant lesions in patients with a history of HPV cervical neoplasia by using a routine diagnosis process to complete the clinical and histologic differential diagnosis when confronted with ambiguous situations.

Five successive waves of SARS-CoV-2 infection in the Central African Republic: a prospective observational study from 2020-2022.

Introduction: the National Laboratory of Clinical Biology and Public Health (NLBPH) in Bangui in the Central African Republic (CAR) carries out the vast majority of molecular screening tests for SARS-CoV-2 infection nationwide. This study aimed to show the contribution of molecular diagnosis and genomic surveillance in monitoring the evolution of longitudinal variations of the SARS-CoV-2 infection epidemic in CAR between 2020 and the end of 2022. Methods: this is an observational study on the variations in the prevalence of detection of SARS-CoV-2 by RT-PCR at the NLCBPH from nasopharyngeal samples taken prospectively over a period of 3 years since the beginning of the COVID-19 epidemic. A subgroup of SARS-CoV-2 positive samples was selected for molecular sequencing performed by Illumina® and MinIon® at the National Institute for Biomedical Research in Kinshasa, Democratic Republic of the Congo. Results: from March 2020 to December 31th, 2022, 88,442 RT-PCR tests were carried out (4/5 of the country) and detected 9,156 cases of SARS-CoV-2 infection in 5 successive waves. The average age of the patients was 39.8 years (extremes ranging from to 92 years). Age(P=0.001), sex(P=0.001) and symptom presentation(P=0.001) were significantly associated with RT-PCR test positivity. Among the different variants identified during successive waves, the Omicron variant predominated during the last two waves. Conclusion: this prospective study over a period of 3 years, marked by 5 successive waves, made it possible to report that age, sex and the presence of clinical symptoms are associated with RT-PCR positivity. Among the different variants identified during successive waves, the Omicron variant predominated during the last two waves.

Incidence and risk factors for tuberculosis among people living with HIV in Bangui: A cohort study.

Objectives: The objectives of this study were to determine the incidence and risk factors of tuberculosis (TB) among people living with HIV (PLHIV). Methods: A cohort study was carried out in an HIV infection management centre in Bangui. PLHIV aged 18 or older, with no history of TB, enrolled between January 1, 2017 and December 31, 2018 were included in the study. The chi-square test was used only to compare the proportions at the 5% significance level. To determine the risk factors, we used the Cox regression adjusted hazard ratio, using Epi Info 7 software. Results: A total of 677 patients including 618 (91.28%) on antiretroviral therapy were included in the study. The median age was 34 with extremes ranging from 18 to 57. Of the patients followed, 104 developed TB. The overall incidence of TB was 15.37 (104/677) cases per 100 PLHIV-years. This incidence was 13.10 (81/618) cases per 100 in patients on ART-years and 38.99 (23/59) cases per 100 patients on pre-ART-years. In pre-ART patients the incidence of TB was therefore almost 3 times higher than that of PLHIV on ART (p = 0.03). WHO clinical stages III and IV (p = 0.02), absence of ART (p = 0.03), poor adherence (p = 0.004) and low functional capacity (p = 0.04) were the risk factors associated with the occurrence of TB among PLHIV in Bangui. Conclusions: The high incidence of TB in our context is essentially linked to delay in diagnosis and the quality of care. Early initiation of antiretroviral therapy, systematic screening for TB in PLHIV upon entry into the active queue and better monitoring of patients on ART are strongly recommended.

Diagnostic performances of Exacto® Triplex rapid test for diagnosis of HIV/HCV/HBsAg: a multicenter, cross-sectional, field study in the Central African Republic.

Introduction: the Exacto® Triplex HIV/HCV/HBsAg (Biosynex, Strasbourg, France) consists in lateral flow, immunochromatographic rapid diagnostic test simultaneously detecting human immunodeficiency virus (HIV)-1 and HIV-2 and hepatitis C virus (HCV)- specific antibodies (IgG and IgM) and hepatitis B virus (HBV) surface antigen (HBsAg) in serum, plasma and whole blood. We herein evaluated its diagnostic performances in the Central African Republic (CAR). Methods: cross-sectional study was conducted on prospectively collected panel of 550 sera from adult inpatients living in Bangui, including 200 HIV-positive, 100 HBsAg-positive, 50 HCV-positive, 200 negatives to three viruses according to reference immuno-enzymatic serological tests including Murex HCV (Diasorin, Saluggia, Italy) for HCV, Murex HBsAg (Diasorin) for HBV, Genscreen ULTRA HIV Ag-Ab HIV-1/2 Version 2 (Bio-Rad, Marnes-la-Coquette, France) and Murex HIV 1.2.0 Ag/Ab Combination (Diasorin), the 2 tests associated in the parallel algorithm for the reference strategy for the diagnosis of HIV in CAR. Serum samples were tested blindly in duplicate. The findings are reported following the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) guidelines. Results: the Exacto® Triplex showed 99.5% (95% CI; 98.5-100.0), 96.0% [90.6-100.0] and 99.0% [97.1-100.0] sensitivities for HIV, HCV and HBsAg, respectively. The specificity, positive and negative predictive values (PPV and NPV) were 100.0% for all three viruses. The Youden's J index and Cohen's κ coefficient were 0.99 for HIV and HBsAg. For HCV, Youden's J and Cohen's κ coefficient were 0.96 and 0.98, respectively. In the epidemiological context of the CAR, the PPV and NPV for all three viral infections were high (≥99.0% to 100%). Conclusion: taken together, our STROBE-compliant study demonstrates that the Exacto® Triplex HIV/HCV/HBsAg showed high sensitivity and specificity for HIV and HBsAg (≥99.0%), and relatively high sensitivity (96.0%) and high specificity (100%) for HCV. These analytical performances are within the limits required by the WHO (i.e. sensitivity ≥99.0% and specificity ≥98.0%) for HIV and HBV. The Exacto® Triplex HIV/HCV/HBsAg is user-friendly at low cost, and appears highly desirable for routine use in the CAR, and likely other Central African countries.

Analytical performances of Exacto® HIV self-test in the Central African Republic.

We herein evaluated the analytical performances of the CE-IVD capillary blood Exacto® HIV self-test (Biosynex, Strasbourg, France) in the Central African Republic (CAR). A cross-sectional study was conducted on a representative national panel of 200 sera positive for HIV and 200 negative for HIV, randomly selected thorough the CAR for HIV seroprevalence surveillance survey, according to reference test. The Exacto® HIV self-test showed 99.5% (95% CI: 98.2-99.9) sensitivity and 100.0% (95% CI: 99.0-100.0) specificity. The Youden´s J index and Cohen´s Kappa coefficient were 0.995. At HIV-1 seroprevalence of 3.5% in the general adult population of the CAR, the positive and negative predictive values were 100% (95% CI: 99.0-100) and 99.9% (95% CI: 98.9-100), respectively. The results are within the limits required by the WHO (i.e. sensitivity ≥ 99.0% and specificity ≥ 98.0%), making Exacto® HIV self-test suitable for routine use in the CAR.

Severe relapse of SARS-CoV-2 infection in a kidney transplant recipient with negative nasopharyngeal SARS-CoV-2 RT-PCR after rituximab.

Immunocompromised patients may experience prolonged viral shedding after their initial SARS-CoV-2 infection, however, symptomatic relapses after remission currently remain rare. We herein describe a severe COVID-19 relapse case of a kidney transplant recipient (KTR) following rituximab therapy, 3 months after a moderate COVID-19 infection, despite viral clearance after recovery of the first episode. During the clinical relapse, the diagnosis was established on a broncho-alveolar lavage specimen (BAL) by RT-PCR. The infectivity of the BAL sample was confirmed on a cell culture assay. Whole genome sequencing confirmed the presence of an identical stain (Clade 20A). However, it had an acquired G142D mutation and a larger deletion of 3-amino-acids at position 143-145. These mutations located within the N-terminal domain are suggested to play a role in viral entry. The diagnosis of a COVID-19 relapse should be considered in the setting of unexplained persistent fever and/or respiratory symptoms in KTRs (especially for those after rituximab therapy), even in patients with previous negative naso-pharyngeal SARS-CoV-2 PCR.

Review of authorship for COVID-19 research conducted during the 2020 first-wave epidemic in Africa reveals emergence of promising African biomedical research and persisting asymmetry of international collaborations.

OBJECTIVES: The contribution of African authors to the biomedical literature is small. We evaluated the African and non-African scientific production published in the international literature on the COVID-19 in Africa during the first year of the epidemic (2020). METHODS: Papers on COVID-19 in Africa were extracted from the Medline (PubMed) database for bibliometric analysis including the proportions of three leading and last authors by study type, study country, authors' and laboratories/institutions' countries of affiliation and journal ranking. RESULTS: A total of 160 articles fulfilling the inclusion criteria were analysed. The majority (91.3%) was produced by half (53.7%) of African countries, with important regional disparities, and generally without sources of funding mentioned. The majority (>85.0) of authors in lead positions (first, second, third and last authors) were Africans. Only a small number (8.7%) of studies on COVID-19 in Africa were carried out by laboratories not on the African continent (mainly Europe, USA and China) and generally received funding. The last and first authors were more frequently of non-African origin in journals with an Impact Factor ranking ≥1, and more frequently of African origin in journals with a lower ranking (< 1). The first and last non-African authors tended to report their studies in high ranking ≥1 journals. CONCLUSIONS: Our study demonstrates that the emergence of promising African research capable of publishing in indexed but low-impact factor medical journals and reveals the persistence of a North-South asymmetry in international cooperation in biomedical research with Africa.

Analytical performances of the AMPLIQUICK® Respiratory Triplex assay for simultaneous detection and differentiation of SARS-CoV-2, influenza A/B and respiratory syncytial viruses in respiratory specimens.

Although patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A, influenza B and respiratory syncytial virus (RSV) show comparable or very similar manifestations, the therapeutic approaches of these respiratory viral infections are different, which requires an accurate diagnosis. Recently, the novel multiplex real-time reverse transcription-polymerase chain reaction assay AMPLIQUICK® Respiratory Triplex (BioSynex SA, Illkirch-Graffenstaden, France) allows simultaneous detection and differentiation of SARS-CoV-2, influenza A, influenza B, and RSV in respiratory tract samples. We herein evaluated the performance of the AMPLIQUICK® Respiratory Triplex for the detection of the four viruses in respiratory specimens, using Allplex™ Respiratory Panel 1 and 2019-nCoV assays (Seegene, Seoul, Korea) as reference comparator assays. A total of 359 archived predetermined respiratory samples, including 83, 145, 19 and 95 positive specimens for SARS-CoV-2, influenza A, influenza B and RSV respectively, were included. The AMPLIQUICK® Respiratory Triplex showed high concordance with the reference assays, with an overall agreement for SARS-CoV-2, influenza A, influenza B, and RSV at 97.6%, 98.8%, 98.3% and 100.0%, respectively, and high κ values ranging from 0.93 to 1.00, indicating an almost perfect agreement between assays. Furthermore, high correlations of cycle threshold (Ct) values were observed for positive samples of the four viruses between the AMPLIQUICK® Respiratory Triplex and comparator assays, with an overall high agreement between Ct values assessed by Bland-Altman analyses. In conclusion, these observations demonstrate that the multiplex AMPLIQUICK® Respiratory Triplex is a reliable assay for the qualitative detection and differentiation of SARS-CoV-2, influenza A, influenza B, and RSV in respiratory specimens, which may prove useful for streamlining diagnostics during the winter influenza-seasons.

Analytical performance of the point-of-care BIOSYNEX COVID-19 Ag BSS for the detection of SARS-CoV-2 nucleocapsid protein in nasopharyngeal swabs: a prospective field evaluation during the COVID-19 third wave in France.

BACKGROUND: The accuracy and reliability of rapid diagnostic tests are critical for monitoring and diagnosing SARS-CoV-2 infection in the general population. This study aimed to evaluate the analytical performance of the BIOSYNEX COVID-19 Ag BSS (Biosynex Swiss SA, Fribourg, Switzerland) antigen rapid diagnostic test (BIOSYNEX Ag-RDT), which targets the SARS-CoV-2 N-nucleocapsid protein for the diagnosis of COVID-19. The Ag-RDT was compared with a real-time RT-PCR (rtRT-PCR) as gold standard for performance measurement. METHODS: Two nasopharyngeal flocked swabs were prospectively collected simultaneously in March and April 2021 from 967 individuals aged ≥ 18 years tested for SARS-CoV-2 in two private laboratories, Paris, France. RESULTS: Overall, the Ag-RDT demonstrated high sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 81.8%, 99.6%, 96.6%, and 97.5%, respectively. The agreement (97.0%), reliability assessed using Cohen's κ-coefficient (0.87), and accuracy evaluated using Youden index (J) (81.6%) in detecting SARS-CoV-2 were high. The analytical performance of the Ag-RDT remained high when there was significant viral shedding (i.e., N gene Ct values ≤ 33 on reference RT-PCR). The sensitivity was only 55.2% in case of low or very low viral excretion (Ct > 33). CONCLUSIONS: The BIOSYNEX Ag-RDT is a promising, potentially simple diagnostic tool, especially in symptomatic COVID-19 patients with substantial viral excretion in the nasopharynx.

Circulating Ubiquitous RNA, A Highly Predictive and Prognostic Biomarker in Hospitalized Coronavirus Disease 2019 (COVID-19) Patients.

BACKGROUND: Approximately 15-30% of hospitalized coronavirus disease 2019 (COVID-19) patients develop acute respiratory distress syndrome, systemic tissue injury, and/or multi-organ failure leading to death in around 45% of cases. There is a clear need for biomarkers that quantify tissue injury, predict clinical outcomes, and guide the clinical management of hospitalized COVID-19 patients. METHODS: We herein report the quantification by droplet-based digital polymerase chain reaction (ddPCR) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNAemia and the plasmatic release of a ubiquitous human intracellular marker, the ribonuclease P (RNase P) in order to evaluate tissue injury and cell lysis in the plasma of 139 COVID-19 hospitalized patients at admission. RESULTS: We confirmed that SARS-CoV-2 RNAemia was associated with clinical severity of COVID-19 patients. In addition, we showed that plasmatic RNase P RNAemia at admission was also highly correlated with disease severity (P < .001) and invasive mechanical ventilation status (P < .001) but not with pulmonary severity. Altogether, these results indicate a consequent cell lysis process in severe and critical patients but not systematically due to lung cell death. Finally, the plasmatic RNase P RNA value was also significantly associated with overall survival. CONCLUSIONS: Viral and ubiquitous blood biomarkers monitored by ddPCR could be useful for the clinical monitoring and the management of hospitalized COVID-19 patients. Moreover, these results could pave the way for new and more personalized circulating biomarkers in COVID-19, and more generally in infectious diseases, specific from each patient organ injury profile.

Evaluation of the Practicability of Biosynex Antigen Self-Test COVID-19 AG+ for the Detection of SARS-CoV-2 Nucleocapsid Protein from Self-Collected Nasal Mid-Turbinate Secretions in the General Public in France.

Due to their ease-of-use, lateral flow assay SARS-CoV-2 antigen-detecting rapid diagnostic tests could be suitable candidates for antigen-detecting rapid diagnostic self-test (Ag-RDST). We evaluated the practicability of the Ag-RDST BIOSYNEX Antigen Self-Test COVID-19 Ag+ (Biosynex Swiss SA, Freiburg, Switzerland), using self-collected nasal secretions from the turbinate medium (NMT), in 106 prospectively included adult volunteers living in Paris, France. The majority of the participants correctly understood the instructions for use (94.4%; 95% confidence interval (CI): 88.3-97.4), showing a great ability to perform the entire self-test procedure to obtain a valid and interpretable result (100%; 95% CI: 96.5-100), and demonstrated the ability to correctly interpret test results (96.2%; 95% CI: 94.2-97.5) with a high level of general satisfaction. About one in eight participants (# 15%) needed verbal help to perform or interpret the test, and only 3.8% of test results were misinterpreted. By reference to multiplex real-time RT-PCR, the Ag-RDST showed 90.9% and 100% sensitivity and specificity, respectively, and high agreement (98.1%), reliability (0.94), and accuracy (90.9%) to detect SARS-CoV-2 antigen. Taken together, our study demonstrates the high usability and accuracy of BIOSYNEX Antigen Self-Test COVID-19 Ag+ for supervised self-collected NMT sampling in an unselected adult population living in France.

Release of infectious virus and cytokines in nasopharyngeal swabs from individuals infected with non-alpha or alpha SARS-CoV-2 variants: an observational retrospective study.

BACKGROUND: The dynamics of SARS-CoV-2 alpha variant shedding and immune responses at the nasal mucosa remain poorly characterised. METHODS: We measured infectious viral release, antibodies and cytokines in 426 PCR+ nasopharyngeal swabs from individuals harboring non-alpha or alpha variants. FINDINGS: With both lineages, viral titers were variable, ranging from 0 to >106 infectious units. Rapid antigenic diagnostic tests were positive in 94% of samples with infectious virus. 68 % of individuals carried infectious virus within two days after onset of symptoms. This proportion decreased overtime. Viable virus was detected up to 14 days. Samples containing anti-spike IgG or IgA did not generally harbor infectious virus. Ct values were slightly but not significantly lower with alpha. This variant was characterized by a fast decrease of infectivity overtime and a marked release of 13 cytokines (including IFN-b, IP-10 and IL-10). INTERPRETATION: The alpha variant displays modified viral decay and cytokine profiles at the nasopharyngeal mucosae during symptomatic infection. FUNDING: This retrospective study has been funded by Institut Pasteur, ANRS, Vaccine Research Institute, Labex IBEID, ANR/FRM and IDISCOVR, Fondation pour la Recherche Médicale.

No SARS-CoV-2 reinfection among staff health-care workers: Prospective hospital-wide screening during the first and second waves in Paris.

OBJECTIVES: Risk of reinfection with SARS-CoV-2 among health-care workers (HCWs) is unknown. We assessed the incidence rate of SARS-CoV-2 reinfection in the real-life setting of a longitudinal observational cohort of HCWs from the Hôpital Européen Georges Pompidou, Assistance Publique-Hôpitaux de Paris, France, during the first and second waves of COVID-19 epidemic. METHODS: From March to December 2020, HCWs were subjected to molecular and serology testing of SARS-CoV-2. Reinfection was defined as a positive test result during the first wave, either by serology or PCR, followed by a positive PCR during the second wave. Evolution of COVID-19 status of HWCs was assessed by a Sankey diagram. RESULTS: A total of 7765 tests (4579 PCR and 3186 serology) were carried out and 4168 HCWs had at least one test result during the follow-up period with a positivity rate of 15.9%. No case of reinfection during the second wave could be observed among 102 positive HCWs of the first wave, nor among 175 HCWs found positive by PCR during the second wave who were negative during the first wave. CONCLUSIONS: SARS-CoV-2 reinfection was not observed among HCWs, suggesting a protective immunity against reinfection that lasts at least 8 months post infection.

Uptake of HIV/AIDS Services Following a Positive Self-Test Is Lower in Men Than Women in the Democratic Republic of the Congo.

As far as HIV self-testing (HIVST) is concerned, proving the link to HIV care for users with a positive result contributes to understanding the implementation of HIVST. We sought to examine whether there were differences by sex in the uptake of HIV services following a positive self-test in the Democratic Republic of the Congo (DRC). This was a mixed-methods study exploring linkage to care for HIVST through a secondary analysis of collected data from three pilot surveys recently conducted in three cities (Kinshasa, Kisangani, and Kindu) during 2018 and 2020 in the DRC. Linkage to HIV care was defined as delayed when observed beyond 1 week. A total of 1,652 individuals were self-tested for HIV. Overall, the proportion of linkage to HIV care was high (n = 258; 82.2%) among individuals having a positive result with HIV self-test (n = 314), but it was significantly lower in men (65.2%) than women (89.2%). Furthermore, linkage to HIV care of men was significantly delayed as compared with that of women (40.0 vs. 20.7%). These findings show a lower uptake of care following a positive self-test in men than women. This trend already previously observed in sub-Saharan Africa shed light on the need to increase linkages to care among men newly diagnosed through HIV self-testing.