Titel Deelnemers "SARS-CoV-2 seroprevalence among nursing home residents in March 2022 : brief communication on results of the scope-2 study (SARS-COV-2 seroprevalence)" "Eline Meyers, Ellen Deschepper, Elza Duysburgh, Liselore De Rop, Tine De Burghgraeve, Pauline Van Ngoc, Marina Di Gregorio, Simon Delogne, Anja Coen, Laëtitia Buret, Samuel Coenen, An De Sutter, Béatrice Scholtes, Jan verbakel, Piet Cools, Stefan Heytens" "Man-specific lectins from plants, fungi, algae and cyanobacteria, as potential blockers for SARS-CoV, MERS-CoV and SARS-CoV-2 (COVID-19) coronaviruses : biomedical perspectives" "Annick Barre, Els Van Damme, Mathias Simplicien, Sophie Le Poder, Bernard Klonjkowski, Hervé Benoist, David Peyrade, Pierre Rougé" "Betacoronaviruses, responsible for the ""Severe Acute Respiratory Syndrome"" (SARS) and the ""Middle East Respiratory Syndrome"" (MERS), use the spikes protruding from the virion envelope to attach and subsequently infect the host cells. The coronavirus spike (S) proteins contain receptor binding domains (RBD), allowing the specific recognition of either the dipeptidyl peptidase CD23 (MERS-CoV) or the angiotensin-converting enzyme ACE2 (SARS-Cov, SARS-CoV-2) host cell receptors. The heavily glycosylated S protein includes both complex and high-mannose type N-glycans that are well exposed at the surface of the spikes. A detailed analysis of the carbohydrate-binding specificity of mannose-binding lectins from plants, algae, fungi, and bacteria, revealed that, depending on their origin, they preferentially recognize either complex type N-glycans, or high-mannose type N-glycans. Since both complex and high-mannose glycans substantially decorate the S proteins, mannose-specific lectins are potentially useful glycan probes for targeting the SARS-CoV, MERS-CoV, and SARS-CoV-2 virions. Mannose-binding legume lectins, like pea lectin, and monocot mannose-binding lectins, like snowdrop lectin or the algal lectin griffithsin, which specifically recognize complex N-glycans and high-mannose glycans, respectively, are particularly adapted for targeting coronaviruses. The biomedical prospects of targeting coronaviruses with mannose-specific lectins are wide-ranging including detection, immobilization, prevention, and control of coronavirus infection." "Diagnostic performance of the SARS-CoV-2 S1RBD IgG ELISA (immunodiagnostics) for the quantitative detection of SARS-CoV-2 antibodies on dried blood spots" "Eline Meyers, Anja Coen, An De Sutter, Elizaveta Padalko, Steven Callens, Linos Vandekerckhove, Wojciech Witkowski, Stefan Heytens, Piet Cools" "Dried Blood Spots (DBS) are broadly used in SARS-CoV-2 surveillance studies, reporting either the presence or absence of SARS-CoV-2 antibodies. However, quantitative follow-up has become increasingly important to monitor humoral vaccine responses. Therefore, we aimed to evaluate the performance of DBS for the detection of anti-spike SARS-CoV-2 antibody concentrations using a commercially available assay, reporting in a standardised unitage (International Units/mL; IU/mL). To assess the sensitivity and specificity of the ImmunoDiagnostics ELISA on serum and DBS for SARS-CoV-2 antibody detection, we analysed 72 paired DBS and serum samples. The SARS-CoV-2 51 IgG ELISA kit (EUROIMMUN) on serum was used as the reference method. We performed a statistical assessment to optimise the cutoff value for DBS and serum and assessed the correlation between DBS and serum antibody concentrations. We found that anti-spike SARS-CoV-2 antibody concentrations detected in DBS are highly correlated to those detected in paired serum (Pearson correlation 0.98; p-value < 0.0001), allowing to assess serum antibody concentration using DBS. The optimal cut-off for antibody detection on DBS was found to be 26 IU/mL, with 98.1% sensitivity and 100% specificity. For serum, the optimal cut-off was 14 IU/mL, with 100% sensitivity and 100% specificity. Therefore, we conclude that the ImmunoDiagnostics ELISA kit has optimal performance in the detection of SARS-CoV-2 antibodies on both DBS and serum. This makes DBS ideal for large-scale follow-up of humoral SARS-CoV-2 immune responses, as it is an easy but valuable sampling method for quantification of SARS-CoV-2 antibodies, compared to serum." "A dual-antigen self-amplifying RNA SARS-CoV-2 vaccine induces potent humoral and cellular immune responses and protects against SARS-CoV-2 variants through T cell-mediated immunity" "Sean McCafferty, A.K.M. Ashiqul Haque, Aster Vandierendonck, Brian Weidensee, Magalie Plovyt, Magdalena Stuchlikova, Nathalie Francois, Sophie Valembois, Leo Heyndrickx, Johan Michiels, Kevin Ariën, Linos Vandekerckhove, Rana Abdelnabi, Caroline S. Foo, Johan Neyts, Itishri Sahu, Niek N. Sanders" "Self-amplifying RNA vaccines may induce equivalent or more potent immune responses at lower doses compared to non -repli-cating mRNA vaccines via amplified antigen expression. In this paper, we demonstrate that 1mg of an LNP-formulated dual -antigen self-amplifying RNA vaccine (ZIP1642), encoding both the S-RBD and N antigen, elicits considerably higher neutral-izing antibody titers against Wuhan-like Beta B.1.351 and Delta B.1.617.2 SARS-CoV-2 variants compared to those of convales-cent patients. In addition, ZIP1642 vaccination in mice expanded both S-and N-specific CD3+CD4+ and CD3+CD8+ T cells and caused a Th1 shifted cytokine response. We demon-strate that the induction of such dual antigen-targeted cell -medi-ated immune response may provide better protection against variants displaying highly mutated Spike proteins, as infectious viral loads of both Wuhan-like and Beta variants were decreased after challenge of ZIP1642 vaccinated hamsters. Supported by these results, we encourage redirecting focus toward the induc-tion of multiple antigen-targeted cell-mediated immunity in addition to neutralizing antibody responses to bypass waning antibody responses and attenuate infectious breakthrough and disease severity of future SARS-CoV-2 variants." "Serological response in health care workers after a single dose of SARS-CoV-2 vaccine using six automated SARS-CoV-2 antibody assays" "Matthias Cuykx, Olivier Mortele, Sofie Schouwers, Anissa Meskal, Ilse Hoffbauer, Bart Peeters" "Spike (S)-and nucleocapsid (N)-specific serological assay responses were determined before and/or after first dose SARS-CoV-2 vaccination in 22 individuals. S-specific assays quantified antibodies after vaccination with significant higher levels in participants with a previous infection. Be cautious combining N-/S-specific assay results, potentially differentiating post-infection/vaccination immunization as assay-specific N-anti-body waning was observed. (c) 2021 Elsevier Inc. All rights reserved." "Age-dependent seroprevalence of SARS-CoV-2 antibodies in school-aged children from areas with low and high community transmission" "Mathieu Roelants, Joanna Merckx, Niel HENS, Isabelle Desombere, Els Duysburgh, Lise Boey, Corinne Vandermeulen" "It is not yet clear to what extent SARS-CoV-2 infection rates in children reflect community transmission, nor whether infection rates differ between primary schoolchildren and young teenagers. A cross-sectional serosurvey compared the SARS-CoV2 attack-rate in a sample of 362 children recruited from September 21 to October 6, 2020, in primary (ages 6-12) or lower secondary school (ages 12-15) in a municipality with low community transmission (Pelt) to a municipality with high community transmission (Alken) in Belgium. Children were equally distributed over grades and regions. Blood samples were tested for the presence of antibodies to SARS-CoV-2 with an enzyme-linked immunosorbent assay. We found anti-SARS-CoV-2 antibodies in 4.4% of children in the low transmission region and in 14.4% of children in the high transmission region. None of the primary schoolchildren were seropositive in the low transmission region, whereas the seroprevalence among primary and secondary schoolchildren did not differ significantly in the high transmission region. None of the seropositive children suffered from severe disease. Children who were in contact with a confirmed case (RR 2.9; 95%CI 1.6-4.5), who participated in extracurricular activities (RR 5.6; 95%CI 1.2-25.3), or whose caregiver is a healthcare worker who had contact with COVID-19 patients (RR 2.2; 95%CI 1.0-4.6) were at higher risk of seropositivity. If SARS-CoV2 circulation in the community is high, this will be reflected in the pediatric population with similar infection rates in children aged 6-12 years and 12-15 years. What is Known: Children are generally less affected by COVID-19 than adults but SARS-CoV2 infection rates among children are not well known. There were large regional differences in infection rates during the first wave of the SARS-CoV2 pandemic. What is New: None of the primary schoolchildren (6-12 years) were seropositive for SARS-CoV2 in an area with a low community transmission, but infection rates were higher in adolescents (12-15 years). In an area with high community transmission, seroprevalence rates in younger children were more comparable to those in adolescents." "Reconstruction of SARS-CoV-2 outbreaks in a primary school using epidemiological and genomic data" "Cécile KREMER, Andrea TORNERI, Pieter LIBIN, C Meex, MP Hayette, S Bontems, K Durkin, M Artesi, V Bours, P Lemey, G Darcis, Niel HENS, C Meuris" "Mathematicalmodelling studies have shown that repetitive screening canbeused tomitigate SARS-CoV2 transmission inprimary schoolswhile keeping schools open. However, notmuch is knownabout how transmissionprogresseswithin schools andwhether there is a riskof importation tohouseholds. During theacademicyear2020–2021, aprospectivesurveillancestudyusingrepetitivescreeningwasconductedin aprimary school andassociatedhouseholds inLiège (Belgium). SARS-CoV-2 screeningwas performedvia throatwashingeitheronceor twiceaweek.Weusedgenomicandepidemiological data toreconstruct the observedschooloutbreaksusingtwodifferentmodels.Theoutbreaker2model combines informationonthe generationtimeandcontactpatternswithamodelofsequenceevolution.ForcomparisonwealsousedSCOTTI, aphylogeneticmodel basedon the structuredcoalescent. Inaddition,weperformeda simulationstudy to investigatehowtheaccuracyofestimatedpositivityratesinaschooldependsontheproportionofaschoolthat issampledinarepetitivescreeningstrategy.WefoundnodifferenceinSARS-CoV-2positivitybetweenchildren andadults andchildrenwerenotmoreoftenasymptomaticcompared toadults. Bothmodels foroutbreak reconstruction revealed that transmissionoccurredmainlywithin the school environment. Uncertainty in outbreakreconstructionwas lowestwhenincludinggenomicaswellasepidemiologicaldata.Wefoundthat observedweeklypositivityrates areagoodapproximation to the trueweeklypositivityrate, especially in children, evenwhenonly25%of theschool populationis sampled.Theseresults indicate that, inaddition to reducing infections as shown inmodelling studies, repetitive screening inschool settings can lead toa betterunderstandingof theextentof transmissioninschoolsduringapandemicandimportationriskat the communitylevel." "Splanchnic vein thrombosis associated with SARS-CoV-2 infection : a VALDIG case–control study" "Pierre Deltenre, Audrey Payancé, Laure Elkrief, Vincenzo La Mura, Florent Artru, Anna Baiges, Jean-Paul Cervoni, Louise China, Isabelle Colle, Elise Lemaitre, Dietmar Schiller, Christophe Bureau, Odile Goria, Isabelle Ollivier, Alexandre Nuzzo, Pierre-Emmanuel Rautou, Aurélie Plessier, VALDIG EASL consortium, Bogdan Procopet" "Background & Aims: Whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a risk factor for splanchnic vein thrombosis (SVT) is unknown. This study aims to assess the impact of SARS-CoV-2 infection on the presentation and prognosis of recent SVT and to identify specific characteristics of SARS-CoV-2-associated SVT.Methods: This is a retrospective study collecting health-related data of 27 patients presenting with recent SVT in the context of SARS-CoV-2 infection in 12 Vascular Liver Disease Group (VALDIG) centres and in comparison with 494 patients with recent SVT before the SARS-CoV-2 pandemic.Results: Twenty-one patients with SARS-CoV-2 had portal vein thrombosis with or without thrombosis of another splanchnic vein, two had superior mesenteric vein thrombosis, one had splenic vein thrombosis, and three had hepatic vein thrombosis. Diagnosis of SVT was made 10 days (95% CI 0-24 days) after the diagnosis of SARS-CoV-2 infection. Fever (52 vs. 15%; p" "The prior infection with SARS-CoV-2 study (PICOV) in nursing home residents and staff : study protocol description and presentation of preliminary findings on symptoms" "ME Goossens, KY Neven, P Pannus, C Barbezange, I Thomas, S Van Gucht, K Dierick, MN Schmickler, Mathieu Verbrugghe, N Van Loon, KK Ariën, A Marchant, S Goriely, I Desombere" "Background The COVID-19 pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has presented itself as one of the most important health concerns of the 2020's, and hit the geriatric population the hardest. The presence of co-morbidities and immune ageing in the elderly lead to an increased susceptibility to COVID-19, as is the case for other influenza-like illnesses (ILI) or acute respiratory tract infections (ARI). However, little is known, about the impact of a previous or current infection on the other in terms of susceptibility, immune response, and clinical course. The aim of the ""Prior Infection with SARS-COV-2"" (PICOV) study is to compare the time to occurrence of an ILI or ARI between participants with a confirmed past SARS-CoV-2 infection (previously infected) and those without a confirmed past infection (naive) in residents and staff members of nursing homes. This paper describes the study design and population characteristics at baseline. Methods In 26 Belgian nursing homes, all eligible residents and staff members were invited to participate, resulting in 1,226 participants. They were classified as naive or previously infected based on the presence of detectable SARS-CoV-2 antibodies and/or a positive RT-qPCR result before participation in the study. Symptoms from a prior SARS-CoV-2 infection between March and August 2020 were compared between previously infected residents and staff members. Results Infection naive nursing home residents reported fewer symptoms than previously infected residents: on average 1.9 and 3.1 symptoms, respectively (p = 0.016). The same effect was observed for infection naive staff members and previously infected staff members (3.1 and 6.1 symptoms, respectively; p" "Variant analysis of SARS-CoV-2 genomes from Belgian military personnel engaged in overseas missions and operations" "Jean-Paul Pirnay, Philippe Selhorst, Samuel L. Hong, Christel Cochez, Barney Potter, Piet Maes, Mauro Petrillo, Gytis Dudas, Vincent Claes, Yolien Van der Beken, Gilbert Verbeken, Julie Degueldre, Simon Dellicour, Lize Cuypers, France T'Sas, Guy Van den Eede, Bruno VERHASSELT, Wouter Weuts, Cedric Smets, Jan Mertens, Philippe Geeraerts, Kevin Ariën, Emmanuel André, Pierre Neirinckx, Patrick Soentjens, Guy Baele" "More than a year after the first identification of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as the causative agent of the 2019 coronavirus disease (COVID-19) in China, the emergence and spread of genomic variants of this virus through travel raise concerns regarding the introduction of lineages in previously unaffected regions, requiring adequate containment strategies. Concomitantly, such introductions fuel worries about a possible increase in transmissibility and disease severity, as well as a possible decrease in vaccine efficacy. Military personnel are frequently deployed on missions around the world. As part of a COVID-19 risk mitigation strategy, Belgian Armed Forces that engaged in missions and operations abroad were screened (7683 RT-qPCR tests), pre- and post-mission, for the presence of SARS-CoV-2, including the identification of viral lineages. Nine distinct viral genotypes were identified in soldiers returning from operations in Niger, the Democratic Republic of the Congo, Afghanistan, and Mali. The SARS-CoV-2 variants belonged to major clades 19B, 20A, and 20B (Nextstrain nomenclature), and included ""variant of interest"" B.1.525, ""variant under monitoring"" A.27, as well as lineages B.1.214, B.1, B.1.1.254, and A (pangolin nomenclature), some of which are internationally monitored due to the specific mutations they harbor. Through contact tracing and phylogenetic analysis, we show that isolation and testing policies implemented by the Belgian military command appear to have been successful in containing the influx and transmission of these distinct SARS-CoV-2 variants into military and civilian populations."