Full-length genome sequencing of RNA viruses-How the approach can enlighten us on hepatitis C and hepatitis E viruses.

Among the five main viruses responsible for human hepatitis, hepatitis C virus (HCV) and hepatitis E virus (HEV) are different while sharing similarities. Both viruses can be transmitted by blood or derivatives whereas HEV can also follow environmental or zoonotic routes. These highly variable RNA viruses can cause chronic hepatitis potentially leading to hepatocarcinoma. HCV and HEV can develop new structures and functions under selective pressure to adapt to host immunity, human tissues, treatments or even various animal reservoirs. Elsewhere, with directly acting antiviral treatments, HCV can be eradicated whereas HEV is an emerging pathogen against which specific treatments have to be improved. As a unique molecular tool able to explore viral genomic plasticity, full-length genome (FLG) sequencing has become easier, faster and cheaper. The present review will show how FLG sequencing can explore these RNA viruses with the aim to investigate key genomics data to improve basic knowledge, patients' healthcare and preventive tools.

Factors associated with the emergence of integrase resistance mutations in patients failing dual or triple integrase inhibitor-based regimens in a French national survey.

BACKGROUND: Successful 2-drug regimens (2DRs) for HIV were made possible by the availability of drugs combining potency and tolerability with a high genetic barrier to resistance. How these deal with resistance development/re-emergence, compared with 3DRs, is thus of paramount importance. MATERIALS AND METHODS: A national survey including patients who were either naive or experienced with any 2DR or 3DR but failing integrase strand transfer inhibitor (INSTI)-containing regimens [two consecutive plasma viral load (VL) values >50 copies/mL] was conducted between 2014 and 2019. Genotypic resistance tests were interpreted with the v28 ANRS algorithm. RESULTS: Overall, 1104 patients failing any INSTI-containing regimen (2DRs, n = 207; 3DRs, n = 897) were analysed. Five hundred and seventy-seven (52.3%) patients were infected with a B subtype and 527 (47.3%) with non-B subtypes. Overall, 644 (58%) patients showed no known integrase resistance mutations at failure. In multivariate analysis, factors associated with the emergence of at least one integrase mutation were: high VL at failure (OR = 1.24 per 1 log10 copies/mL increase); non-B versus B subtype (OR = 1.75); low genotypic sensitivity score (GSS) (OR = 0.10 for GSS = 2 versus GSS = 0-0.5); and dolutegravir versus raltegravir (OR = 0.46). Although 3DRs versus 2DRs reached statistical significance in univariate analysis (OR = 0.59, P = 0.007), the variable is not retained in the final model. CONCLUSIONS: This study is one of the largest studies characterizing integrase resistance in patients failing any INSTI-containing 2DR or 3DR in routine clinical care and reveals factors associated with emergence of integrase resistance that should be taken into consideration in clinical management. No difference was evidenced between patients receiving a 2DR or a 3DR.

Variability in molecular characteristics of Hepatitis E virus quasispecies could modify viral surface properties and transmission.

Hepatitis E virus (HEV) usually causes self-limited liver diseases but can also result in severe cases. Genotypes 1 (G1) and 2 circulate in developing countries are human-restricted and waterborne, while zoonotic G3 and G4 circulating in industrialized countries preferentially infect human through consumption of contaminated meat. Our aims were to identify amino acid patterns in HEV variants that could be involved in pathogenicity or in transmission modes, related to their impact on antigenicity and viral surface hydrophobicity. HEV sequences from human (n = 37) and environmental origins (wild boar [n = 3], pig slaughterhouse effluent [n = 6] and urban wastewater [n = 2]) were collected for the characterization of quasispecies using ultra-deep sequencing (ORF2/ORF3 overlap). Predictive and functional assays were carried out to investigate viral particle antigenicity and hydrophobicity. Most quasispecies showed a major variant while a mixture was observed in urban wastewater and in one chronically infected patient. Amino acid signatures were identified, as a rabbit-linked HEV pattern in two infected patients, or the S68L (ORF2) / H81C (ORF3) residue mostly identified in wild boars. By comparison with environmental strains, molecular patterns less likely represented in humans were identified. Patterns impacting viral hydrophobicity and/or antigenicity were also observed, and the higher hydrophobicity of HEV naked particles compared with the enveloped forms was demonstrated. HEV variants isolated from human and environment present molecular patterns that could impact their surface properties as well as their transmission. These molecular patterns may concern only one minor variant of a quasispecies and could emerge under selective pressure.

Signs of tracheobronchitis may constitute the principal finding on the lung SPECT/CT images of COVID-19 patients.

BACKGROUND: This study aimed to analyze the rates of tracheobronchitis signs observed on the ventilation scans of COVID-19 patients with shortness of breath, with comparisons to a non-COVID population. METHODS: Lung scintigraphy was collected in 10 such COVID patients, as well as from a non-COVID population investigated outside the epidemic wave period, on a CZT-SPECT/CT system, with ventilation images recorded with 99mTc-labeled Technegas® and perfusion images with 99mTc-labeled albumin macroaggregates. RESULTS: A diffuse tracheobronchial uptake was observed on the ventilation scans from 3 COVID patients (30%), whereas this rate was 3% (3/90) in the non-COVID group (P = 0.013). These 3 patients had no laryngeal extension of Technegas® uptake and limited parenchymal lung abnormalities. Follow-up scintigraphy demonstrated the withdrawal of tracheobronchitis signs in two cases, and the advent of a severe pulmonary embolism in one. CONCLUSION: Signs of tracheobronchitis may constitute the principal finding on lung SPECT/CT images of COVID-19 patients with shortness of breath.

CT abnormalities evocative of lung infection are associated with lower 18F-FDG uptake in confirmed COVID-19 patients.

PURPOSE: CT signs that are evocative of lung COVID-19 infections have been extensively described, whereas 18F-FDG-PET signs have not. Our current study aimed to identify specific COVID-19 18F-FDG-PET signs in patients that were (i) suspected to have a lung infection based on 18F-FDG-PET/CT recorded during the COVID-19 outbreak and (ii) whose COVID-19 diagnosis was definitely established or excluded by appropriate viral testing. METHODS: Twenty-two consecutive patients referred for routine 18F-FDG-PET/CT examinations during the COVID-19 outbreak (March 25th to May 15th 2020) and for whom CT slices were evocative of a lung infection were included in the study. All patients had undergone a SARS-COV-2 diagnostic test to confirm COVID-19 infection (positivity was based on molecular and/or serological tests) or exclude it (negativity of at least the serological test). RESULTS: Eleven patients were confirmed to be affected by COVID-19 (COVID+), whereas the other eleven patients were not (COVID-) and were predominantly suspected of having bacterial pneumonia. CT abnormalities were not significantly different between COVID+ and COVID- groups, although trends toward larger CT abnormalities (p = 0.16) and lower rates of consolidation patterns (0.09) were observed in the COVID+ group. The maximal standardized uptake values (SUVmax) of lung areas with CT abnormalities were however significantly lower in the COVID+ than the COVID- group (3.7 ± 1.9 vs. 6.9 ± 4.1, p = 0.03), with the highest SUVmax consistently not associated with COVID-19. CONCLUSION: Among CT abnormalities evocative of lung infection, those related to COVID-19 are associated with a more limited 18F-FDG uptake. This observation may help improve our ability to detect COVID-19 patients.

Changes in characteristics and management among patients with ST-elevation myocardial infarction due to COVID-19 infection.

OBJECTIVES: To assess changes in characteristics and management among ST-elevation myocardial infarction (STEMI) patients with coronavirus disease (COVID-19) who underwent primary percutaneous coronary intervention. METHODS: Our prospective, monocentric study enrolled all STEMI patients who underwent PPCI during the COVID-19 outbreak (n = 83). This cohort was first compared with a previous cohort of STEMI patients (2008-2017, n = 1,552 patients) and was then dichotomized into a non-COVID-19 group (n = 72) and COVID-19 group (n = 11). RESULTS: In comparison with the pre-outbreak period, patients during the outbreak period were older (59.6 ± 12.9 vs. 62.6 ± 12.2, p = .03) with a delayed seek to care (mean delay first symptoms-balloon 3.8 ± 3 vs. .7.4 ± 7.7, p < .001) resulting in a two-fold higher in-hospital mortality (non COVID-19 4.3% vs. COVID-19 8.4%, p = .07). Among the 83 STEMI patients admitted during the outbreak period, 11 patients were infected by COVID-19. Higher biological markers of inflammation (C-reactive protein: 28 ± 39 vs. 98 ± 97 mg/L, p = .04), of fibrinolysis (D-dimer: 804 ± 1,500 vs. 3,128 ± 2,458 µg/L, p = .02), and antiphospholipid antibodies in four cases were observed in the COVID-19 group. In this group, angiographic data also differed: a thrombotic myocardial infarction nonatherosclerotic coronary occlusion (MINOCA) was observed in 11 cases (1.4% vs. 54.5%, p < .001) and associated with higher post-procedure distal embolization (30.6% vs. 72.7%, p = .007). The in hospital mortality was significantly higher in the COVID-19 group (5.6% vs. 27.3%, p = .016). CONCLUSION: The COVID-19 outbreak implies deep changes in the etiopathogenesis and therapeutic management of STEMI patients with COVID-19. The impact on early and long-term outcomes of systemic inflammation and hypercoagulability in this specific population is warranted.

Performance evaluation of an automated SARS-CoV-2 Ag test for the diagnosis of COVID-19 infection on nasopharyngeal swabs.

OBJECTIVES: The detection of SARS-CoV-2 in infected people is a key tool to help in controlling COVID-19 pandemic. Like rapid antigenic tests, automated antigen tests, that present the advantage of a higher throughput flow, may be of interest. The LIAISON® SARS-CoV-2 Ag test was evaluated for the quantification of SARS-CoV-2 nucleocapsid antigen in nasopharyngeal swabs by comparison to RT-PCR. METHODS: The study involved 378 nasopharyngeal samples (UTM® and FLOQSwab™, Copan Diagnostics), including 46 swabs positive for SARS-CoV-2 by RT-PCR. These samples came from asymptomatic (n=99, 26.2%) or symptomatic people (n=279, 73.8%), at different times from symptom onset. The samples were analyzed on LIAISON® XL. RESULTS: The overall specificity was 99.4% (CI95% [98.6-100]). The negative predictive value reached 100% in asymptomatic people. Among the 46 positive samples, the overall sensitivity was 84.8% (CI95% [74.4-95.2]), reached 91.9% (CI95% [83.1-100]) in the first fourth days after symptoms onset and was 100% for Cq values ≤25. Antigen was not detected in samples with Cq values >25. Similar results were observed on nasopharyngeal swabs coming from patients infected with the 20I/501Y.V1 variant or the 20H/501Y.V2 variant. CONCLUSIONS: According to technical performances, the LIAISON® SARS-CoV-2 Ag test may be a useful tool for COVID-19 diagnosis, especially during the first four days of symptoms.

[How genetic variability of hepatitis E virus (VHE) may impact its clinical relevance and transmission]. / Comment la variabilité génétique du virus de l'hépatite E (VHE) peut influencer ses manifestations cliniques et sa circulation dans l'environnement.

Hepatitis E virus is the main cause of acute hepatitis worldwide. The dichotomy between waterborne human-restricted genotypes 1 and 2 circulating in developing countries and zoonotic genotypes 3 and 4 infecting human through consumption of contaminated meat in industrialized countries is currently discussed, with the detection of HEV in waters of industrialized nations. Chronic infections are described in immunocomprommised patients, as well as extra hepatic syndromes. In vivo and in vitro data have shown that HEV genetic variability can impact the bioclinical relevance of the infection, by highlighting mutations associated with severity. Genetic variability has also to be considered when exploring transmission ways, with the description of new animal reservoirs and new strains able to infect humans. HEV genetic variability is one of the keys to better control its transmission and to adapt diagnostic tools and strategies, with the aim to protect vulnerable populations.

Resistance to integrase inhibitors: a national study in HIV-1-infected treatment-naive and -experienced patients.

OBJECTIVES: To describe integrase strand transfer inhibitor (INSTI) resistance profiles and factors associated with resistance in antiretroviral-naive and -experienced patients failing an INSTI-based regimen in clinical practice. METHODS: Data were collected from patients failing an INSTI-containing regimen in a multicentre French study between 2014 and 2017. Failure was defined as two consecutive plasma viral loads (VL) >50 copies/mL. Reverse transcriptase, protease and integrase coding regions were sequenced at baseline and failure. INSTI resistance-associated mutations (RAMs) included in the Agence Nationale de Recherches sur le SIDA genotypic algorithm were investigated. RESULTS: Among the 674 patients, 359 were failing on raltegravir, 154 on elvitegravir and 161 on dolutegravir therapy. Overall, 90% were experienced patients and 389 (58%) patients showed no INSTI RAMs at failure. The strongest factors associated with emergence of at least one INSTI mutation were high VL at failure (OR = 1.2 per 1 log10 copies/mL increase) and low genotypic sensitivity score (GSS) (OR = 0.08 for GSS ≥3 versus GSS = 0-0.5). Patients failing dolutegravir also had significantly fewer INSTI RAMs at failure than patients failing raltegravir (OR = 0.57, P = 0.02) or elvitegravir (OR = 0.45, P = 0.005). Among the 68 patients failing a first-line regimen, 11/41 (27%) patients on raltegravir, 7/18 (39%) on elvitegravir and 0/9 on dolutegravir had viruses with emergent INSTI RAMs at failure. CONCLUSIONS: These results confirmed the robustness of dolutegravir regarding resistance selection in integrase in the case of virological failure in routine clinical care.

Antiretroviral-treated HIV-1 patients can harbour resistant viruses in CSF despite an undetectable viral load in plasma.

Background: HIV therapy reduces the CSF HIV RNA viral load (VL) and prevents disorders related to HIV encephalitis. However, these brain disorders may persist in some cases. A large population of antiretroviral-treated patients who had a VL > 1.7 log 10 copies/mL in CSF with detectable or undetectable VL in plasma associated with cognitive impairment was studied, in order to characterize discriminatory factors of these two patient populations. Methods: Blood and CSF samples were collected at the time of neurological disorders for 227 patients in 22 centres in France and 1 centre in Switzerland. Genotypic HIV resistance tests were performed on CSF. The genotypic susceptibility score was calculated according to the last Agence Nationale de Recherche sur le Sida et les hépatites virales Action Coordonnée 11 (ANRS AC11) genotype interpretation algorithm. Results: Among the 227 studied patients with VL > 1.7 log 10 copies/mL in CSF, 195 had VL detectable in plasma [median (IQR) HIV RNA was 3.7 (2.7-4.7) log 10 copies/mL] and 32 had discordant VL in plasma (VL < 1.7 log 10 copies/mL). The CSF VL was lower (median 2.8 versus 4.0 log 10 copies/mL; P < 0.001) and the CD4 cell count was higher (median 476 versus 214 cells/mm 3 ; P < 0.001) in the group of patients with VL < 1.7 log 10 copies/mL in plasma compared with patients with plasma VL > 1.7 log 10 copies/mL. Resistance to antiretrovirals was observed in CSF for the two groups of patients. Conclusions: Fourteen percent of this population of patients with cognitive impairment and detectable VL in CSF had well controlled VL in plasma. Thus, it is important to explore CSF HIV (VL and genotype) even if the HIV VL is controlled in plasma because HIV resistance may be observed.

Evaluation of Virological Microparticle Enzyme Immunoassay According to the ISO 15189: Real-Life Experience in a University Hospital.

BACKGROUND: The International Standard ISO 15189 based on the ISO 9001:2008 emphasizes specific requirements for quality and ability of medical laboratories. The accreditation of medical laboratories according to ISO 15189 includes the validation of biological methods, which depends on collection of bibliographic data and experimental proofs. Moreover, these results must be compared to provider data sheets and independent scientific data. In the immunodiagnostic field, independent published data are deeply lacking. The aim of our work was to share experience of method validation for virological immune markers on the widely used Architect i2000sr. METHODS: After risk analysis, intra- and inter-assay variability, and inter-sample contamination were evaluated for each method, and sensitivity was investigated for antigen detection tests. A comparison between the two Architect i2000sr available in our laboratory was also performed. RESULTS: All tested methods were consistent with the manufacturer data (from the data sheet). No inter-sample contamination was observed. Both devices are broadly equivalent and can be used indifferently or as a backup solution of the other. CONCLUSIONS: To our knowledge, those results are the first independent complete data on the reliability of the Architect i2000sr in real-life experience. These data are needed to the accreditation of our platform and potentially useful for the accreditation of other laboratories using the same equipment.

Cross-resistance to elvitegravir and dolutegravir in 502 patients failing on raltegravir: a French national study of raltegravir-experienced HIV-1-infected patients.

OBJECTIVES: The objectives of this study were to determine the prevalence and patterns of resistance to integrase strand transfer inhibitors (INSTIs) in patients experiencing virological failure on raltegravir-based ART and the impact on susceptibility to INSTIs (raltegravir, elvitegravir and dolutegravir). PATIENTS AND METHODS: Data were collected from 502 treatment-experienced patients failing a raltegravir-containing regimen in a multicentre study. Reverse transcriptase, protease and integrase were sequenced at failure for each patient. INSTI resistance-associated mutations investigated were those included in the last ANRS genotypic algorithm (v23). RESULTS: Among the 502 patients, at failure, median baseline HIV-1 RNA (viral load) was 2.9 log10 copies/mL. Patients had been previously exposed to a median of five NRTIs, one NNRTI and three PIs. Seventy-one percent harboured HIV-1 subtype B and the most frequent non-B subtype was CRF02_AG (13.3%). The most frequent mutations observed were N155H/S (19.1%), Q148G/H/K/R (15.4%) and Y143C/G/H/R/S (6.7%). At failure, viruses were considered as fully susceptible to all INSTIs in 61.0% of cases, whilst 38.6% were considered as resistant to raltegravir, 34.9% to elvitegravir and 13.9% to dolutegravir. In the case of resistance to raltegravir, viruses were considered as susceptible to elvitegravir in 11% and to dolutegravir in 64% of cases. High HIV-1 viral load at failure (P < 0.001) and low genotypic sensitivity score of the associated treatment with raltegravir (P < 0.001) were associated with the presence of raltegravir-associated mutations at failure. Q148 mutations were selected more frequently in B subtypes versus non-B subtypes (P = 0.004). CONCLUSIONS: This study shows that a high proportion of viruses remain susceptible to dolutegravir in the case of failure on a raltegravir-containing regimen.

Antiretroviral-naive and -treated HIV-1 patients can harbour more resistant viruses in CSF than in plasma.

OBJECTIVES: The neurological disorders in HIV-1-infected patients remain prevalent. The HIV-1 resistance in plasma and CSF was compared in patients with neurological disorders in a multicentre study. METHODS: Blood and CSF samples were collected at time of neurological disorders for 244 patients. The viral loads were >50 copies/mL in both compartments and bulk genotypic tests were realized. RESULTS: On 244 patients, 89 and 155 were antiretroviral (ARV) naive and ARV treated, respectively. In ARV-naive patients, detection of mutations in CSF and not in plasma were reported for the reverse transcriptase (RT) gene in 2/89 patients (2.2%) and for the protease gene in 1/89 patients (1.1%). In ARV-treated patients, 19/152 (12.5%) patients had HIV-1 mutations only in the CSF for the RT gene and 30/151 (19.8%) for the protease gene. Two mutations appeared statistically more prevalent in the CSF than in plasma: M41L (P=0.0455) and T215Y (P=0.0455). CONCLUSIONS: In most cases, resistance mutations were present and similar in both studied compartments. However, in 3.4% of ARV-naive and 8.8% of ARV-treated patients, the virus was more resistant in CSF than in plasma. These results support the need for genotypic resistance testing when lumbar puncture is performed.

Combination of Epstein-Barr virus nuclear antigen 1, 3 and lytic antigen BZLF1 peptide pools allows fast and efficient stimulation of Epstein-Barr virus-specific T cells for adoptive immunotherapy.

BACKGROUND: Epstein-Barr virus (EBV) infection is a major cause of morbidity following hematopoietic stem cell transplantation. EBV-infected B cells may not respond to rituximab treatment and may lead to a life-threatening post-transplantation lymphoproliferative disorder. Adoptive cellular immunotherapy using EBV-lymphoblastoid cell lines (LCL) as stimulating antigen has proved effective in restoring specific immunity. However, EBV presents several immunodominant antigens, and developing a swift and effective clinical-grade immunotherapy relies on the definition of a Good Manufacturing Practices (GMP) universal stimulating antigen. METHODS: Peripheral blood mononuclear cells (PBMCs) from six donors with a cellular immune response against EBV were immunoselected after stimulation with a new EBV antigen associated with an EBNA3 peptide pool. RESULTS: After immunoselection, a mean of 0.53 ± 0.25 × 106 cells was recovered consisting of a mean of 24.77 ± 18.01% CD4⁺-secreting interferon (IFN)-γ and 51.42 ± 26.92% CD8⁺-secreting IFN-γ. The T memory stem cell sub-population was identified. EBV-specific T cells were expanded in vitro, and their ability to secrete IFN-γ and to proliferate after re-stimulation with EBV antigen was confirmed. A specific lysis was observed against autologous target cells pulsed with EBV peptide pools (57.6 ± 11.5%) and against autologous EBV-LCL (18.3 ± 7.3%). A mean decrease of 94.7 ± 3.3% in alloreactivity against third-party donor mononuclear cells with EBV-specific T cells was observed compared with PBMCs before selection. CONCLUSIONS: Our results show that a combination of peptide pools including EBNA3 is needed to generate EBV-specific T cells with good specific cytotoxicity and devoid of alloreactivity, but as yet GMP grade is not fully achieved.

Seroprevalence and SARS-CoV-2 invasion in general populations: A scoping review over the first year of the pandemic.

Since the beginning of the COVID-19 pandemic, counting infected people has underestimated asymptomatic cases. This literature scoping review assessed the seroprevalence progression in general populations worldwide over the first year of the pandemic. Seroprevalence studies were searched in PubMed, Web of Science and medRxiv databases up to early April 2021. Inclusion criteria were a general population of all ages or blood donors as a proxy. All articles were screened for the title and abstract by two readers, and data were extracted from selected articles. Discrepancies were resolved with a third reader. From 139 articles (including 6 reviews), the seroprevalence estimated in 41 countries ranged from 0 to 69%, with a heterogenous increase over time and continents, unevenly distributed among countries (differences up to 69%) and sometimes among regions within a country (up to 10%). The seroprevalence of asymptomatic cases ranged from 0% to 31.5%. Seropositivity risk factors included low income, low education, low smoking frequency, deprived area residency, high number of children, densely populated centres, and presence of a case in a household. This review of seroprevalence studies over the first year of the pandemic documented the progression of this virus across the world in time and space and the risk factors that influenced its spread.

SARS-CoV-2 seroprevalence in healthcare workers and risk factors.

BACKGROUND: Exposure of healthcare workers (HCW) to SARS-CoV-2 is a public health concern. Not only are HCWs particularly exposed to SARS-CoV-2, but their contamination can also weaken the healthcare system. METHODS: We analyzed exposure of French University Hospital HCWs to SARS-CoV-2 through history of positive RT-PCR test and SARS-CoV-2 seroprevalence. Potential risk factors, such as age, BMI, having children or not, working in a COVID-19 unit, or smoking were explored. RESULTS: From May to June 2020, among the 8960 employees of the University Hospital of Nancy, a serological test was performed in 4696 HCWs. The average (SD) age was 40.4 (11.4) years, and the sample included 3926 women (83.6%). Of the 4696 HCWs, 1050 were smokers (22.4%). Among them, 2231 HCWs had a history of COVID-19 symptoms and/or flu-like syndrome (47.5%) and 238 were seropositive (5.1%). Neither gender, sex, BMI, nor having children were associated with a history of positive RT-PCR test or seropositive status. Previous work in a COVID-19 unit was associated with a history of positive RT-PCR test (p = 0.045), but not with seroprevalence (p = 0.215). As expected, history of COVID-19 clinical manifestations was more frequent in HCWs with positive serology than in HCWs with negative serology (adjusted OR = 1.9, 95%CI [1.4-2.5], p < 0.001). Less expected, smoking was associated with a reduced risk of seropositivity among HCWs (adjusted OR = 0.6, 95%CI [0.4-0.9], p = 0.019). CONCLUSION: HCW are patently exposed to SARS-CoV-2. Care to COVID-19 patients was not associated with a higher SARS-CoV-2 seroprevalence. Smoking appears here associated to a lower seroprevalence.

Evaluation of a Lateral Flow Immunoassay COVIDTECH® SARS-CoV-2 IgM/IgG Antibody Rapid Test.

The new coronavirus severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is responsible for severe respiratory illness (i.e., COVID-19). RT-PCR of respiratory samples is the gold standard for COVID-19 diagnosis, and serological tests may contribute to the detection of post-infection and post-vaccination immunity and enable seroprevalence studies. The lateral flow immunoassay (LFIA) COVIDTECH® SARS-CoV-2 IgM/IgG antibody rapid test that detects anti-SARS-CoV-2 IgM and IgG using an S protein recombinant antigen has been independently evaluated in two laboratories. The specificity evaluated for 65 pre-pandemic samples was 100% for IgM/IgG. An analysis of samples from patients with RT-PCR-confirmed infection revealed that IgM/IgG antibodies were detected in 18/26 (69%) samples before day 13 and in 58/58 (100%) samples from day 14 post-symptom onset. Before day 14 post-symptom onset, the COVIDTECH Test was less sensitive than other LFIA method (BIOSYNEX COVID-19 BSS IgM/IgG) and a chemiluminescent immunoassay (LIAISON® SARS-CoV-2 TrimericS IgG assay). Overall, this LFIA method is suitable for SARS-CoV-2 serological diagnosis for patients after > 14 days since the onset of symptoms.

Anti-spike IgG antibody kinetics following the second and third doses of BNT162b2 vaccine in nursing home residents.

BACKGROUND: Duration of post-vaccination protection against COVID-19 in nursing home (NH) residents is a critical issue. The objective of this study was to estimate the duration of the IgG(S) response to the mRNA BNT162b2 vaccine in NH residents with (COV-Yes) or without (COV-No) history of SARS-CoV-2 infection. METHODS: A 574 COV-Yes and COV-No NH residents were included in 2 cohorts: Main (n = 115, median age 87 years) or Confirmatory (n = 459, median age 89 years). IgG(S) quantification was carried out at three different time points following the BNT162b2 vaccine: three (1st) and seven (2nd) months after the 2nd dose, and 1 month after the 3rd dose (3rd quantification) in the Main cohort, and twice (2nd and 3rd) in the Confirmatory cohort. The seroneutralization capacity according to COVID-19 history was also measured in a subgroup of patients. RESULTS: Neutralization capacity was strongly correlated with IgG(S) levels (R2 :76%) without any difference between COV-Yes and COV-No groups for the same levels of IgG(S). After the 2nd dose, duration of the assumed robust protection (IgG(S) >264 BAU/ml) was two-fold higher in the COV-Yes vs. COV-No group: 12.60 (10.69-14.44) versus 5.76 (3.91-8.64) months, with this advantage mainly due to the higher IgG(S) titers after the 2nd dose and secondary to a slower decay over time. After the 3rd dose, duration of robust protection was estimated at 11.87 (9.88-14.87) (COV-Yes) and 8.95 (6.85-11.04) (COV-No) months. These results were similar in both cohorts. CONCLUSIONS AND RELEVANCE: In old subjects living in NH, history of SARS-CoV-2 infection provides a clear advantage in the magnitude and duration of high IgG(S) titers following the 2nd dose. Importantly, the 3rd dose induces a much more pronounced IgG(S) response than the 2nd dose in COV-No subjects, the effect of which should be able to ensure a prolonged protection against severe forms of COVID-19 in these subjects.

SARS-CoV-2 Variability in Patients and Wastewaters-Potential Immuno-Modulation during the Shift from Delta to Omicron.

The continuous emergence of SARS-CoV-2 variants favors potential co-infections and/or viral mutation events, leading to possible new biological properties. The aim of this work was to characterize SARS-CoV-2 genetic variability during the Delta-Omicron shift in patients and in a neighboring wastewater treatment plant (WWTP) in the same urban area. The surveillance of SARS-CoV-2 was performed by routine screening of positive samples by single nucleotide polymorphism analysis within the S gene. Moreover, additionally to national systematic whole genome sequencing (WGS) once a week in SARS-CoV-2-positive patients, WGS was also applied when mutational profiles were difficult to interpret by routine screening. Thus, WGS was performed on 414 respiratory samples and on four wastewater samples, northeastern France. This allowed us to report (i) the temporally concordant Delta to Omicron viral shift in patients and wastewaters; (ii) the characterization of 21J (Delta) and 21K (Omicron)/BA.1-21L (Omicron)/BA.2-BA.4 mixtures from humans or environmental samples; (iii) the mapping of composite mutations and the predicted impact on immune properties in the viral Spike protein.

Seroprevalence of SARS-CoV-2, Symptom Profiles and Sero-Neutralization in a Suburban Area, France.

The World Health Organisation recommends monitoring the circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We investigated anti-SARS-CoV-2 total immunoglobulin (IgT) antibody seroprevalence and in vitro sero-neutralization in Nancy, France, in spring 2020. Individuals were randomly sampled from electoral lists and invited with household members over 5 years old to be tested for anti-SARS-CoV-2 (IgT, i.e., IgA/IgG/IgM) antibodies by ELISA (Bio-rad); the sero-neutralization activity was evaluated on Vero CCL-81 cells. Among 2006 individuals, the raw seroprevalence was 2.1% (95% confidence interval 1.5 to 2.9), was highest for 20- to 34-year-old participants (4.7% (2.3 to 8.4)), within than out of socially deprived area (2.5% vs. 1%, p = 0.02) and with than without intra-family infection (p < 10-6). Moreover, 25% of participants presented at least one COVID-19 symptom associated with SARS-CoV-2 positivity (p < 10-13), with highly discriminant anosmia or ageusia (odds ratio 27.8 [13.9 to 54.5]); 16.3% (6.8 to 30.7) of seropositive individuals were asymptomatic. Positive sero-neutralization was demonstrated in vitro for 31/43 seropositive subjects. Regarding the very low seroprevalence, a preventive effect of the lockdown in March 2020 can be assumed for the summer, but a second COVID-19 wave, as expected, could be subsequently observed in this poorly immunized population.