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Background: The COVID-19 pandemic has been striking for three years and, despite the regular arise of new variants, populations are now widely immune and protected from severe symptoms. However, immunocompromised patients still have worse clinical outcomes, higher mortality and rarely develop effective immunity through vaccination or infection. Here, we studied the temporal distribution of infections, viral loads (VL) as well as the viral genetic diversity among an immunocompromised patient cohort, between January 2021 and September 2022. Method(s): Overall, 478 immunocompromised patients (solid organ transplant, HIV positive, cancer, autoimmune disease) and 234 controls (healthcare workers) from Pitie-Salpetriere and Bichat Claude-Bernard University hospitals (Paris, FRANCE) were diagnosed with SARS-CoV-2 infection by RT-qPCR. Whole genome sequencing was performed according to ARTIC protocol on Oxford Nanopore platform. All 712 full viral genomes were used to determine lineages and mapped to Wuhan-Hu-1 reference to produce a maximum likelihood phylogenetic tree (IQTree, 1000 bootstraps). Differences in temporal distributions of infections and VL were assessed using nonparametric statistical tests. Result(s): According to phylogenetic analysis, genomes from SARS-CoV- 2 infecting immunocompromised patients and those infecting healthy individuals are distributed in a similar way. No significant genetic differences can be observed between viral genomes from patients and controls within the different lineages. Temporal distribution of COVID-19 infections were also similar between immunocompromised patients and controls, with the exception of BA.2 variant for which controls were infected earlier (p< 0.001). VL were significantly lower in immunocompromised patients infected with Omicron variants (p=0.04). No differences in VL were observed for Alpha and Delta variants. Conclusion(s): At diagnosis, no intrinsic genetic divergence was observed in virus infecting immunocompromised patients compared to those circulating in the general population. Similarities in temporal distribution of infections between controls and patients suggest that these different groups become infected concomitantly. VL appeared to be lower for Omicron variants in immunocompromised patients. An earlier VL peak of Omicron and a testing of immunocompromised patients hospitalized once severe symptoms have appeared could indicate a delayed testing in these patients, once the replicative phase over. (Figure Presented).
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Background: At the end of 2021, concomitantly with the beginning of Omicron variant circulation, pre-exposure prophylaxis with the dual monoclonal long-acting monoclonal antibodies tixagevimab/cilgavimab became available in France to protect patients non-responding or non-eligible to SARS-CoV-2 vaccination at risk of severe COVID-19. Method(s): This study included patients who received tixagevimab/cilgavimab for pre-exposure prophylaxis independently of vaccination status or previous SARS-CoV-2 infection. This prophylaxis strategy was implemented at the Bichat-Claude Bernard University Hospital, Paris since December 2021 Last date of follow-up was November 1st, 2022. Incident SARS-CoV-2 infections were detected based on positive RT-PCR result and/or anti-nucleocapsid antibodies seroconversion. Severe COVID-19 was defined as an infection leading to an hospitalization requiring oxygenotherapy and/or high dose corticotherapy. Result(s): Among the 275 patients who received a tixagevimab/cilgavimab preexposure prophylaxis, 55% (n=153) were solid organ transplant recipients (50% lung, 46% kidney, 4% heart transplants), 42% (n=116) had an autoimmune disease, and 3% (n=6) had other indications. 51% (n=141) of all patients received rituximab. No severe adverse event of tixagevimab/cilgavimab was observed. Incident SARS-CoV-2 infection was diagnosed in 67 patients (24%). Among them, 59% (n=40) were solid organ transplant recipients, 36% (n=24) had an autoimmune disease and overall 52% had received rituximab. For the 56 patients whose infection date was available, the median delay between the last infusion of tixagevimab/cilgavimab and SARS-CoV-2 infection was 62 days (IQR=[30-97]). During the study period, 57% of incident infections occurred between December 17th, 2021 and May 31st, 2022, when BA.1 and BA.2 were the major Omicron sublineages in France, and 43% between June 1st, 2022 and November 2022 1st, a period during which BA.4 and BA.5 were predominant in France. Severe COVID-19 occurred in 6 patients out of 67 (9%);5 were solid organ transplant recipients and 3 received rituximab. No death due to COVID-19 was reported. Conclusion(s): Overall, 76% of patients receiving pre-exposure prophylaxis with tixagevimab/cilgavimab had no incident SARS-CoV-2 infection during the study period. Severe COVID-19 was observed in 9% of infected patients. These results suggest a potential protective effect in-vivo of tixagevimab/cilgavimab during the study period despite the circulation of different Omicron sublineages.
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Background: Immunocompromised hosts with prolonged SARS-CoV-2 infections have been associated with the emergence of novel mutations, especially in the Spike protein, a key target for vaccines and therapeutics. Here, we conducted a case-control study to measure the genetic diversity of SARSCoV- 2 and to search for immunocompromised-specific minority variants. Method(s): SARS-CoV-2-positive patients with lung/cardiac/kidney transplant, HIV-positive, or treated with high doses of corticosteroids for auto-immune diseases were considered as immunocompromised hosts. SARS-CoV-2-positive healthcare workers with no auto-immune disease were used as controls. Samples were analyzed by RT-qPCR at Pitie-Salpetriere and Bichat Claude-Bernard university hospitals (Paris, France). Samples with Cycle threshold < 30 were selected for SARSCoV- 2 whole-genome sequencing using Oxford Nanopore protocol. Raw sequence data were mapped onto the Wuhan-Hu-1 reference genome, and consensus sequences were produced to determine the lineage. Only sequences covering at least 95% at >=50X depth of the Spike gene were investigated. In-house algorithms were developed to identify all majority and minority mutations in Spike. We defined a minority variant when it was present in >=6% and < 50% of the reads;and a majority variant when it was present in >50%. Result(s): We sequenced SARS-CoV-2 genome from 478 COVID-19- positive immunocompromised patients and 234 controls. More minority non-synonymous mutations in Spike were detected in viruses from immunocompromised hosts, compared to viral genomes from controls, in both Delta (p=0.001) and Omicron (p< 0.001) lineages, but not in Alpha (p=0.66) (Figure 1). Interestingly, among the 52 patients infected with the Delta variant, we concomitantly detected at low frequencies the mutations H655Y, N764K, D796Y, in three patients (associated with different auto-immune disease), that are part of Omicron variants signature mutations. Similarly, some patients (n=7) infected by Omicron BA.1 lineage had R346T at low-frequency, later fixed in Omicron BA.4.6 and BQ.1.1 lineages. None of these mutations were observed in the viral genomes from controls. Conclusion(s): Here, we report a higher genetic diversity in Spike gene among SARS-CoV-2 sequences from immunocompromised hosts for Delta and Omicron lineages. These results suggest that immunocompromised patients are more likely to allow viral genetic diversification and are associated with a risk of emergence of novel SARS-CoV-2 variants. (Figure Presented).
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Serology studies provide limited information on immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This cross-sectional study aimed to assess prevalence and determinants of anti-SARS-CoV-2 cellular immunity in a cohort of heart transplant (HT) recipients. All consecutive HT recipients followed-up at our outpatient clinic between February and June 2022 providing informed consent were included in this observational cross-sectional study. We quantified SARS-CoV-2 Spike (S)-reactive and Nucleocapsid (N)-reactive T cells using enzyme-linked immunospot assay. A positive response was defined as S or N reactivity >8 spots/2 × 105 lymphocytes. Clinical characteristics, laboratory data, immunosuppressive regimen and vaccination status were compared between patients with and without SARS-CoV-2 S-reactive T cells. Categorical variables were described as number (%) and continuous variables with median [IQR]. Among 201 patients (age 58 [45-65] years, 77% males, time since transplantation 51 months [24-81]), 97 (48%) exhibit S-specific T cells, of which 58 had in addition N-reactive T cells. CD4 and CD8 T lymphocyte count, glomerular filtration rate, immunosuppressive regimen were associated with T cell response (Table). Among patients with detectable SARS-Co-V-2 cellular immunity, numbers of S-reactive T cells were higher in patients who had detectable N-reactive T cells (277 vs 93 /106 T cells) (Figure). Our study provides new information on cellular immunity against SARS-CoV-2 in HT recipients. [ FROM AUTHOR] Copyright of Journal of Heart & Lung Transplantation is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)
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La pandémie actuelle liée à l'émergence du SARSCoV-2 en 2019 a considérablement modifié la perception des médecins de l'impact des virus respiratoires et de leur rôle dans les pneumonies aiguës communautaires (PAC). Alors que plus de 25 % des tableaux de PAC chez l'adulte étaient d'origine virale, les virus respiratoires étaient souvent perçus comme des agents pathogènes peu graves. Devant le défi que représente encore à nos jours la documentation microbiologique d'une PAC, l'instauration d'un traitement empirique par antibiotiques est souvent réalisée aux urgences. La pandémie de COVID-19 a surtout mis en exergue le rôle déterminant de la biologie moléculaire et du scanner thoracique dans l'algorithme diagnostique de la PAC. En effet, un diagnostic rapide et fiable est la clé pour améliorer les mesures de précaution et réduire la prescription inutile d'antibiotiques. Du fait de prises en charges très différentes, il est nécessaire de distinguer l'étiologie virale de la bactérienne d'une PAC.Alternate : The current pandemic linked to the emergence of SARS-CoV-2 in 2019 has considerably changed the perception of doctors of the impact of respiratory viruses and their role in community-acquired acute pneumonia (CAP). While more than 25% of CAP in adults were of viral origin, respiratory viruses were often perceived as harmless pathogens. Faced with the challenge that the microbiological documentation of a CAP still represents today, the establishment of empirical antibiotic treatment is often carried out in the emergency room. The COVID-19 pandemic has primarily highlighted the decisive role of molecular biology and chest CT in the diagnostic algorithm of CAP. Indeed, a rapid and reliable diagnosis is the key to improve isolation decisions and reducing the unnecessary prescription of antibiotics. Due to significantly different treatments, it is necessary to distinguish the viral etiology from the bacterial of a CAP.
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The current pandemic linked to the emergence of SARS-CoV-2 in 2019 has considerably changed the perception of doctors of the impact of respiratory viruses and their role in community-acquired acute pneumonia (CAP). While more than 25% of CAP in adults were of viral origin, respiratory viruses were often perceived as harmless pathogens. Faced with the challenge that the microbiological documentation of a CAP still represents today, the establishment of empirical antibiotic treatment is often carried out in the emergency room. The COVID-19 pandemic has primarily highlighted the decisive role of molecular biology and chest CT in the diagnostic algorithm of CAP. Indeed, a rapid and reliable diagnosis is the key to improve isolation decisions and reducing the unnecessary prescription of antibiotics. Due to significantly different treatments, it is necessary to distinguish the viral etiology from the bacterial of a CAP. Copyright © 2022 Lavoisier. All rights reserved.
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Alors que la vaccination anti-SARS-CoV-2 est devenue un enjeu important de la prise en charge des patients atteints de maladies auto-immunes systémiques telles que le lupus érythémateux systémique (LES), nous manquons de données sur l'impact de la vaccination par ARN messager sur l'auto-immunité. Notre objectif était de décrire l'impact de la vaccination par ARNm sur la production d'interféron alpha et l'auto-immunité cellulaire au cours du lupus. Nous avons réalisé une étude prospective, observationnelle, monocentrique au cours de laquelle nous avons inclus des patients atteints de LES, éligibles à la vaccination anti-SARS-CoV-2 par le vaccin BNT162b2 selon les recommandations françaises alors en vigueur. Nous avons secondairement exclu les patients non-naïfs vis-à-vis de l'infection par le SARS-CoV-2 à T0 et les patients sous mycophénolate, azathioprine ou rituximab. Les patients étaient évalués juste avant la première dose, puis à 1 mois (M1), à 3 mois (M3) et à 6 mois (M6) de leur première dose. En plus du suivi clinicobiologique habituel de la maladie, nous avons évalué la production d'IFN-alpha par les cellules dendritiques plasmacytoïdes (pDCs) en cytométrie de flux. Nous avons également quantifié l'auto-immunité T en mesurant la proportion de cellules T activées (CD154+ CD69+) après stimulation des cellules sanguines mononucléées périphériques (PBMCs) par des antigènes nucléaires (U1-RNP, histones, SS-A, SS-B). Trente-six patients lupiques et 11 contrôles sains ont été inclus. Les patients lupiques étaient majoritairement des femmes (31/36, 81 %) d'un âge médian de 44 [36–50] ans. Nous avons observé une augmentation significative de la proportion de pDCs produisant spontanément de l'IFN-alpha à M1 (1,27 % [0,6–2,6]) et M3 (1,25 % [0,87–1,83]) comparativement à T0 (0,64 [0,27–1,09] %, respectivement p < 0,001 et p < 0,01) chez les lupiques. Nous avons observé une augmentation similaire dans le groupe contrôle, mais uniquement à M1 (1,46 [0,95–2,12] %) comparativement à T0 (0,25 [0,12–0,47] %, p < 0,02). Par ailleurs, les pDCs des patients lupiques exprimaient à leur surface plus de marqueurs d'activation CD86 et HLA-DR à M3 que à T0. Concernant la proportion de cellules T auto-réactives des patients lupiques, nous avons observé, qu'après une hausse non significative entre T0 et M1, les cellules auto-réactives diminuaient significativement dans le temps (coefficient β d l'effet fixe associé au temps dans le modèle linéaire à effet mixte = −0,00067, p = 0,015). Nous n'avons pas observé une telle tendance chez les contrôles. Au cours du suivi, nous avons observé 2 poussées cliniques de la maladie. À l'exception de ces patients, nous n'avons pas constaté de modification significative du SLEDAI, du taux d'anti-dsDNA, de C3 ou de C4 dans la cohorte. Chez les patients lupiques, la vaccination anti-SARS-CoV-2 par ARNm entraîne (1) une augmentation modeste infra-clinique de la production spontanée d'IFN-alpha par les pDCs et (2) une diminution des cellules T auto-réactives spécifiques des antigènes nucléaires. (French) [ FROM AUTHOR]
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PurposeVaccination in patients with autoimmune disease like systemic lupus erythematosus (SLE) raises a special concern because its impact on autoimmunity remains partially unknown. While clinical data from large cohort are reassuring [1], very little has been described on the post vaccination immune system reaction. Besides, long-term efficacy of the vaccine, especially regarding T-cell response has not been evaluated in detail.MethodsWe conducted a prospective observational study that included all the adult SLE patients vaccinated by the BNT162b2 anti-SARS-CoV-2 vaccine in a single tertiary medical center in Paris. We evaluated the efficacy and the safety of the vaccine just before the first dose and then one month (M1), three months (M3) and six months (M6) later. Apart from the standard clinical and biological follow-up, we measured, at each time, the proportion of plasmacytoid dendritic cells (PDCs) producing interferon-α (IFN-α) using intracellular flow cytometry staining. We quantified the activation of autoimmune T cells at each visit by stimulating the peripheral blood mononuclear cells (PBMCs) with nuclear antigens and quantifying the proportion of activated (CD154+ CD69+) among non-naïve (CD45-RA -) CD4 T cells. We also evaluated the anti-SARS-CoV-2 T cell response by an Interferon Gamma Release Assay (IGRA) test.ResultsWe included 57 SLE patients and 11 healthy volunteers (HV) vaccinated by the BNT162b2 vaccine according to the French national recommendations. SLE patients were mostly female (49/57, 86.0%) with a median [IQR] age of 44.0 [38.1–50.8] years and a time since SLE diagnosis of 10.8 [4.2–19-8] years. Their treatment regimen was heterogeneous: 47/57 (82.5%) received hydroxychloroquine;35 (61.4%) steroids, and 10 (17.5%) were on another immunosuppressive drug (mycophenolate mofetil, azathioprine or rituximab). We observed only one clinical SLE flare during the post vaccination follow-up. Except for this patient, we observed no modification in the anti-dsDNA titer among SLE patients. At M3 compared to T0, we observed more PDCs producing INF-α in the SLE group: 1.17% [0.72–1.77] vs 0.68% [0.34–1.18], p=0.002 but not in the HV group. The proportion of non-naïve CD4 T cells activated (CD154+ CD69+) by the nuclear antigens did not change after vaccination. Regarding the T cell response, we observed that 71% of the SLE patients had a positive IGRA test at M3, whereas at M6, only 36% of them had a positive IGRA test. The antiviral T cell response correlated well with the humoral response: there was no patient with negative anti-Spike serology and positive IGRA and 78% of patients with a positive serology had a positive IGRA test.ConclusionWe observed that BNT162b2 vaccine had a mild impact on innate and adaptative immunity on SLE patients. The antiviral T cell response was well correlated to the humoral anti-Spike response and decreased significantly from M3 to M6.
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Background: An emergency use authorization was issued in March 2021 for two combinations of monoclonal antibodies (MAbs) for SARS-CoV-2 infected patients at high risk of severe COVID-19. We performed a cohort study of patients receiving early treatment with Bamlanivimab/Etesevimab (B/E) or Casirivimab/Imdevimab (C/I) in a Paris university hospital. Methods: All patients receiving a MAbs therapy from March to July 2021 were included. Prescriptions were systematically advised by a multidisciplinary team. Both MAbs dual therapies were used up to May 12th, then only C/I due to local emergence of Delta variant. Nasopharyngeal swabs (NPS) were performed at diagnosis and 7 days after infusion. Additional NPS were collected for hospitalized patients at day 3 and during follow-up until negative RT-PCR or patients discharge. Viral sequencing was carried out and viral mutations were retained if present at more than 20% of viral subpopulations. Results: Overall, 66 patients (19 ambulatory) received a MAbs dual therapy for a documented SARS-CoV-2 asymptomatic infection or within 5 days after symptoms onset. Patients had a median age of 67 years [IQR=41-75], 53% were male, 30 (45%) were receiving immunosuppressive treatment (17 being solid organ recipients), 8 (12%) had chronic respiratory insufficiency, and 6 (9%) were receiving chemotherapy. Regarding variants, 82% were Alpha, 5% Delta and 13% other variants. 8 patients (12%) died (6 treated with B/E and two with C/I). Five deaths were related to COVID-19 worsening and three were unrelated. Among the surviving patients, 42 (64%) did not require any oxygen and 16 (24%) required low-flow oxygen. No severe adverse event related to MAbs occurred. A slower viral decay was observed among patients receiving B/E than C/I, with 17/29 and 5/13 having <30 Ct at day 7 post-infusion (p=0.3), respectively, and 9/14 and 1/8 at day 14 (p=0.03). Different Spike mutations emergence were observed including Q493R in 7 patients and E484K in 2 patients, all infected with an Alpha variant, and detected from 6 to 18 days after MAbs infusion. Among the 9 mutations, 8 occurred after B/E infusion and one Q493R occurred after C/I infusions. Conclusion: We described safety and efficacy of early MAbs therapies administration in a cohort of 66 patients at risk of severe COVID-19. Emergence of mutations were observed under both therapies, with increased frequency under B/E. Further studies including patients infected by Delta variant and receiving C/I infusion are ongoing.
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Background: Recent studies reported poor to moderate humoral response after two vaccine doses in heart transplant recipients (HTR). Currently, French healthcare authorities recommend 2 and 3 vaccine injections for transplant recipients with and without prior SARS-CoV-2 infection, respectively. This study aimed to evaluate level and durability of humoral immunity with this vaccination strategy. Methods: This single-center cohort study included HTR followed at Paris Bichat hospital between January 2020 and September 2021. Analyses were performed using automated immunoassays (Abbot) to quantify anti-spike IgG (cut-off ≥ 7.1 BAU/mL) and anti-nucleocapsid IgG (cut-off index > 0.49), respectively. Categorical variables were described as number (%) and continuous variables with median (IQR). Results: A total of 181 HTR (75.7% males, age 58 y [47-66]) transplanted between June 1990 and June 2021, with cardiomyopathy (n=95), coronary artery disease (n=61), valvular cardiomyopathy (n=19) or other transplant indications were included. Median time from transplantation to first vaccine dose was 4.2 y [1.8-6.6]. 143 HTR (79%) had no SARS-CoV-2 infection history (HTRn) and 38 (21%) contracted the infection (HTRi) (56% before and 42% after vaccination initiation). After 2 vaccine injections, anti-S IgG seroconversion was observed for only 16% (n=12/76) of HTRn. Overall, anti-S IgG titers were lower in HTRn than in HTRi (0.5 [0.2-2.6] vs 578 [1.4-4449] BAU/mL, respectively, p=0.0001). The 3rd vaccine dose enabled to obtain 42% (n=33/72) of seroconversion among HTRn with median anti-S titers of 3.2 BAU/mL [0.4-35.0]. Only half seroconverters HTRn reached the 260 BAU/mL cut-off chosen by French authorities to define vaccination efficacy. Interestingly, these patients seem to have a sustained humoral response 4 months after the 3rd dose. Conclusion: This study gives new insights on the effect of the 3rd vaccine dose in HTR with low rate of seroconversion and low titers of anti-S IgG but sustained humoral response when seroconversion occurs. Studies on vaccine efficacy against SARS-CoV-2 variants and cell-mediated immune response in this cohort are ongoing.
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Introduction A ce jour, peu de données sont disponibles sur la concordance de la détection des virus respiratoires (en dehors du SARS-CoV2) entre le prélèvement nasopharyngé (NP) et le lavage broncho-alvéolaire (LBA) chez l'adulte. L'objectif de cette étude était de décrire la concordance de leurs résultats. Matériels et méthodes Une analyse rétrospective monocentrique a été réalisée à l'aide des données de 276 adultes suspects de pneumonie et testés par PCR multiplex dans le NP et le LBA à 24 heures d'intervalle. Résultats Les patients étaient majoritairement des hommes (65 %), avec un âge médian de 60 ans[IQR : 50,9-67,8]. 169 patients (61 %) ont été admis en réanimation Nous avons détecté au moins un virus respiratoire dans 95 NP (34 %) et dans 80 BAL (29 %). Comparé au LBA, le NP avait une sensibilité de 71,6 % et une spécificité de 93,4 % et un coefficient Kappa de 0,67. Le même agent pathogène ou combinaison d'agents pathogènes a été observé chez 84 % des patients positifs à la fois sur le NP et le LBA. La grippe B, le parainfluenza, les coronavirus HKU1, NL63, 229E présentaient la concordance la plus élevée (100 %) entre le NP et la LBA, tandis que le coronavirus OC43 et le rhinovirus présentaient la concordance la plus faible (33 % et 67 %, respectivement).Nous avons observé que les patients atteints d'une maladie respiratoire chronique ont une plus faible concordance entre le NP et LBA avec un OR ajusté à 0,5, IC 95 % (0,25-0,97), p = 0,043. Conclusion Dans ce travai, Il y a une bonne concordance entre le NP et le LBA dans la détection des virus respiratoires chez les patients consultant avec une suspicion de pneumonie. Néanmoins, ces données encouragent toujours à réaliser un LBA lorsque cela est possible afin d'obtenir un diagnostic étiologique plus précis. Aucun lien d'intérêt
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Introduction Les populations de sans domicile fixe ont un taux de mortalité supérieur à celui de la population générale. Ceci est en partie en lien avec des maladies chroniques non suivis, des problèmes d’addiction ainsi qu’une exposition plus forte aux maladies transmissibles, en particulier respiratoires. Nous avons réalisé une étude pour évaluer les taux d’attaque, d’hospitalisation et de mortalité liés à l’infection par le SARS-CoV-2 dans une population de résidents de centres d’hébergement pour sans-abri et du personnel à leur contact. Matériels et méthodes Une étude sérologique rétrospective a été réalisée sur l’ensemble des résidents et des membres du personnel de trois centres d’hébergement pour sans-abri entre mars et mai 2020 : 2 centres de lits halte soins santé (LHSS) et un dortoir de femmes. Nous avons inclus tous les adultes présents dans les centres d’hébergement ou décédés d’une infection avérée par le SARS-CoV-2. Les IgG anti-SARS-CoV-2 étaient détectés par le test ELISA « SARS-CoV-2 IgG Architect (Abbott) ». Un cas confirmé de SARS-CoV-2 était défini comme tout participant présentant une PCR ou une sérologie positive. Des sérologies de contrôle ont été prélevées quatre mois après la première sérologie positive. Résultats Nous avons inclus 100 résidents et 83 membres du personnel. Le taux de SARS-CoV-2 confirmé par PCR ou sérologie était de 72/100 (72,0 %) pour les résidents et de 17/83 (20,5 %) pour le personnel. Le taux d’hospitalisation chez les résidents était de 17/72 (25 %) et le taux de décès de 4/72 (5,6 %). Toutes les hospitalisations sauf une et tous les décès sont survenus chez des résidents des LHSS. Trente-quatre sur 68 (50 %) des résidents des LHSS présentaient au moins deux facteurs de risque de forme grave d’infection par le SARS-CoV-2. Les femmes hébergées dans le dortoir étaient plus jeunes, présentaient moins de comorbidité, avaient le taux d’attaque le plus élevé (90,6 %) et une morbidité-mortalité quasi nulle. Cinquante-deux sur 80 (63,4 %) des personnes ayant une première sérologie positive ont eu une sérologie de contrôle à 4 mois de la première sérologie et 8 mois environ de leur infection. Parmi eux, 44 (84,6 %) avaient conservé des sérologies positives. Conclusion Le taux d’attaque du SARS-CoV-2 était extrêmement élevé chez les résidents des centres d’hébergement pour sans-abri par rapport à la population générale. Le risque d’infection grave par le SARS-CoV-2 était fortement associé à la présence de comorbidités à un plus jeune âge. Cette population à risqué doit être considérée comme prioritaire dans les campagnes de vaccination dans l’accès aux logements individuels pour les plus vulnérables.