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Background: Rift Valley fever virus, a pathogen to ruminants, camelids, and humans, is an emerging mosquito-borne bunyavirus currently endemic to Africa and the Arabian Peninsula. Although animals are primarily infected via mosquito bites, humans mainly become infected following contact with infected tissues or fluids of infected animals. There is an urgent need for adequate countermeasures, especially for humans, because effective therapeutics or vaccines are not yet available. Here we assessed the safety, tolerability, and immunogenicity of a next-generation, four-segmented, live-attenuated vaccine candidate, referred to as hRVFV-4s, in humans., Methods: A first-in-human, single-centre, randomised, double-blind, placebo-controlled trial was done in Belgium in which a single dose of hRVFV-4s was administered to healthy volunteers aged 18-45 years. Participants were randomly assigned using an interactive web response system. The study population encompassed 75 participants naive to Rift Valley fever virus infection, divided over three dosage groups (cohorts) of 25 participants each. All participants were followed up until 6 months. Using a staggered dose escalating approach, 20 individuals of each cohort were injected in the deltoid muscle of the non-dominant arm with either 10 4 (low dose), 10 5 (medium dose), or 10 6 (high dose) of 50% tissue culture infectious dose of hRVFV-4s as based on animal data, and five individuals per cohort received formulation buffer as a placebo. Primary outcome measures in the intention-to-treat population were adverse events and tolerability. Secondary outcome measures were vaccine-induced viraemia, vaccine virus shedding, Rift Valley fever virus nucleocapsid antibody responses (with ELISA), and neutralising antibody titres. Furthermore, exploratory objectives included the assessment of cellular immune responses by ELISpot. The trial was registered with the EU Clinical Trials Register, 2022-501460-17-00., Findings: Between August and December, 2022, all 75 participants were vaccinated. No serious adverse events or vaccine-related severe adverse events were reported. Pain at the injection site (51 [85%] of 60 participants) was most frequently reported as solicited local adverse event, and headache (28 [47%] of 60) and fatigue (28 [47%] of 60) as solicited systemic adverse events in the active group. No vaccine virus RNA was detected in any of the blood, saliva, urine, or semen samples. Rift Valley fever virus nucleocapsid antibody responses were detected in most participants who were vaccinated with hRVFV-4s (43 [72%] of 60 on day 14) irrespective of the administered dose. In contrast, a clear dose-response relationship was observed for neutralising antibodies on day 28 with four (20%) of 20 participants responding in the low-dose group, 13 (65%) of 20 responding in the medium-dose group, and all participants (20 [100%] of 20) responding in the high-dose group. Consistent with the antibody responses, cellular immune responses against the nucleocapsid protein were detected in all dose groups, whereas a more dose-dependent response was observed for the Gn and Gc surface glycoproteins. Neutralising antibody titres declined over time, whereas nucleocapsid antibody responses remained relatively stable for at least 6 months., Interpretation: The hRVFV-4s vaccine showed a high safety profile and excellent tolerability across all tested dose regimens, eliciting robust immune responses, particularly with the high-dose administration. The findings strongly support further clinical development of this candidate vaccine for human use., Funding: The Coalition for Epidemic Preparedness Innovations with support from the EU Horizon 2020 programme., Competing Interests: Declaration of interests PJWS and JK are inventors of a patent describing the RVFV-4s vaccine technology and PJWS is the non-executive Scientific Officer of BunyaVax that currently owns the intellectual property of this technology. CP is CEO of BunyaVax. IL-R declares receiving funding from various vaccine manufacturers, paid to CEVAC. GL-R is an independent consultant in vaccinology. All other authors declare no competing interests., (Copyright © 2024 Elsevier Ltd. All rights reserved, including those for text and data mining, AI training, and similar technologies.)

Background: This study investigated the safety, reactogenicity, and immunogenicity in healthy subjects of a Clostridioides difficile vaccine candidate with/without adjuvant, targeting toxins A and B., Methods: In this first-in-human, phase 1, observer-blind study, subjects aged 18-45 years were randomized to receive F2 antigen (n = 10) or placebo (n = 10), and subjects aged 50-70 years to receive F2 antigen plus AS01 adjuvant (n = 45), F2 antigen (n = 45), or placebo (n = 30) in 2 doses 1 month apart. A subcohort (n = 40) received a third dose 15 months later. Solicited adverse events (AEs) were recorded for 7 days and unsolicited AEs for 30 days after each dose. Immunogenicity was assessed at baseline and after each dose., Results: Solicited AEs were transient and most frequent in subjects receiving F2 antigen plus AS01. No serious AEs were considered related to study vaccine. Immunogenicity was substantially higher in subjects receiving F2 antigen plus AS01 than subjects receiving F2 antigen alone. A third dose increased the immune response in subjects with baseline neutralization titers below the assay lower limit of quantitation., Conclusions: The GSK C. difficile vaccine candidate was immunogenic, especially when given with AS01, and was well tolerated with an acceptable safety profile., Clinical Trial Registration: NCT04026009., Competing Interests: Potential conflicts of interest. M. C., B. d. W., G. S. F., A. L., S. M., C. S., and J. P. Y. are employees of GSK. M. E. I. was an employee of GSK at the time of the study. B. d. W., M. E. I., S. M., C. S., G. S. F., and J. P. Y. hold financial equities in GSK. B. d. W. also holds shares in Haleon. G. S. F. was an employee of Janssen Biologics, 3D-PharmXchange Consultancy, and Access to Medicine Foundation over the past 36 months. I. L.-R. reports funding from GSK to her institution for the conduct of this study; and funding to her institution for the conduct of various vaccine trials (non-C. difficile vaccine studies) from Janssen, MSD, Moderna, Curevac, Osivax, Vaccitech, Icosavax, OSE Immunotherapeutics, Icon Genetics, and Virometix. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: We report data from stage 1 of an ongoing 2-staged, phase 1/2 randomized clinical trial with a 4-component generalized modules for membrane antigens-based vaccine against Shigella sonnei and Shigella flexneri 1b, 2a, and 3a (altSonflex1-2-3; GSK)., Methods: Europeans aged 18-50 years (N = 102) were randomized (2:1) to receive 2 injections of altSonflex1-2-3 or placebo at 3- or 6-month interval. Safety and immunogenicity were assessed at prespecified time points., Results: The most common solicited administration-site event (until 7 days after each injection) and unsolicited adverse event (until 28 days after each injection) were pain (altSonflex1-2-3, 97.1%; placebo, 58.8%) and headache (32.4%; 23.5%), respectively. All serotype-specific functional IgG antibodies peaked 14-28 days after injection 1 and remained substantially higher than prevaccination at 3 or 6 months postvaccination; the second injection did not boost but restored the initial immune response. The highest seroresponse rates (≥4-fold increase in titers over baseline) were obtained against S. flexneri 2a (enzyme-linked immunosorbent assay [ELISA] after injection 1, 91.0%; after injection 2 [day 113; day 197], 100%; 97.0% and serum bactericidal activity [SBA] after injection 1, 94.4%; after injection 2, 85.7%; 88.9%) followed by S. sonnei (ELISA after injection 1, 77.6%; after injection 2, 84.6%; 78.8% and SBA after injection 1, 83.3%; after injection 2, 71.4%; 88.9%). Immune responses against S. flexneri 1b and S. flexneri 3a, as measured by both ELISA and SBA, were numerically lower compared to those against S. sonnei and S. flexneri 2a., Conclusions: No safety signals or concerns were identified. altSonflex1-2-3 induced functional serotype-specific immune responses, allowing further clinical development in the target population. Clinical Trials Registration . NCT05073003., Competing Interests: Potential conflicts of interest. U. N. N., F. Ma., E. S., J. J., G. L. C., A. S. B., C. G. V., P. F., E. M., F. N., R. R., I. D. R., J. A., A. M. C., F. B. S., O. R., V. C., F. Mi., A. K. A., and A. P. are or were employees of GSK when the study was designed, initiated, and/or conducted. U. N. N., J. J., G. L. C., A. S. B., C. G. V., F. N., I. D. R., J. A., F. B. S., O. R., V. C., F. Mi., A. K. A., and A. P. hold shares in GSK as part of their remuneration. A. K. A. reports GSK scientific writer support for this study. F. Mi. reports a patent issued on the 4-component Shigella GMMA formulation. I. L. R. reports funding to her institution for the conduct of GSK Vaccines Institute for Global Health (GVGH) studies; being a data safety monitoring board member of a phase 3 (non-Shigella) vaccine trial for Janssen Vaccines; and funding to her institution for the conduct of various vaccine trials (none were Shigella vaccine studies) from GSK, Janssen, Curevac, Osivax, Vaccitech, Icosavax, OSE Immunotherapeutics, Icon Genetics, Virometix, and MSD. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

The pre-clinical validation of cell therapies requires monitoring the biodistribution of transplanted cells in tissues of host organisms. Real-time detection of these cells in the circulatory system and identification of their aggregation state is a crucial piece of information, but necessitates deep penetration and fast imaging with high selectivity, subcellular resolution, and high throughput. In this study, multiphoton-based in-flow detection of human stem cells in whole, unfiltered blood is demonstrated in a microfluidic channel. The approach relies on a multiphoton microscope with diffractive scanning in the direction perpendicular to the flow via a rapidly wavelength-swept laser. Stem cells are labeled with metal oxide harmonic nanoparticles. Thanks to their strong and quasi-instantaneous second harmonic generation (SHG), an imaging rate in excess of 10 000 frames per second is achieved with pixel dwell times of 1 ns, a duration shorter than typical fluorescence lifetimes yet compatible with SHG. Through automated cell identification and segmentation, morphological features of each individual detected event are extracted and cell aggregates are distinguished from isolated cells. This combination of high-speed multiphoton microscopy and high-sensitivity SHG nanoparticle labeling in turbid media promises the detection of rare cells in the bloodstream for assessing novel cell-based therapies., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Seasonal influenza vaccine effectiveness is low. Carbohydrate fatty acid monosulphate ester (CMS), a new oil-in-water adjuvant, has proven potency in animal models with suggested capacity for dose-sparing. The objective was to evaluate safety and immunogenicity of CMS when added to a low-dose influenza vaccine (QIV) in humans. In a randomised, double-blind, active-controlled, first-in-human study, sixty participants (18-50 years) received either 0.5 mg CMS or 2 mg CMS with 1/5th dose QIV, or a full dose QIV without CMS. Adverse events (AE) were monitored until 7 days post-vaccination. Haemagglutinin inhibition (HI) titres in serum and CD4+ T cells in PBMCs were determined at day 0, 7, 28, and 180. Mean age was 37.6 (±10.1) years and 42/60 (70.0%) were female. Pain at injection site (42/60, 86.7%) and headache (34/60, 56.7%) were reported most and more frequently in the 2 mg CMS group. HI titres and the frequency of influenza specific CD4+ T cells were equal across strains for the three cohorts on all visits, increased until day 28 and decreased at day 180 to values higher than baseline. CMS was safe in humans. Humoral and cell-mediated immunogenicity was similar across vaccines, even with 1/5th antigen dose. CMS can have beneficial implications in low-resource settings or in a pandemic context.

Background: Despite the many guidelines for reprocessing of medical instruments, challenges persist such as microbial resistance to biocides, corrosive effects on materials, and time-consuming reprocessing procedures. Ultraviolet (UV) C light-emitting diode (LED) chambers might provide a solution but the integration in healthcare is still in its infancy. Here, we evaluated the efficacy of a novel ZAPARAY ™ UVC LED chamber as a time and energy-efficient alternative for reprocessing of medical instruments for which current disinfection protocols exhibit limitations., Methods: We verified the disinfection efficacy of the UVC LED chamber on a Petri dish and contaminated several medical devices with Staphylococcus aureus ATCC 25923. The bacterial reduction was assessed after 5 min of UVC LED exposure. Additionally, we investigated the impact of rinsing before UVC exposure., Results: We demonstrated a bacterial reduction of 9 log 10 on a Petri dish. Non-rinsed dental tools exhibited varied reduction levels ranging from a 3.23 log 10 to a 6.25 log 10 reduction. Rinsing alone yielded an average reduction of 2.7 log 10 and additional UVC exposure further reduced the bacterial load by an average of 3.65 log 10 . We showed an average 4.90 log 10 reduction on thermistors, 2 log 10 or less on orthodontic pliers, and no reduction on handpieces., Conclusions: This study demonstrates that UVC LED chambers may be used as a standardized substitute for specific (manual) disinfection procedures of certain medical devices, offering a time-efficient and more sustainable alternative. However, its use should be preceded by efficacy testing for each specific type of instrument., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: H.S. is an employee of eLEDricity, M.V.F. was an employee and shareholder of eLEDricity until halfway through the study. D.V. and A.F.K. are shareholders of eLEDricity but were not involved in the analysis or interpretation of the data. All other authors declare they have nothing to disclose., (© 2024 The Authors.)

Background: Respiratory syncytial virus (RSV) fusion protein stabilized in the prefusion conformation (RSVPreF3) was under investigation as a maternal vaccine., Methods: This phase 2, randomized, placebo-controlled, single-dose, multicenter study enrolled healthy, nonpregnant women, randomized 1:1:1:1:1 to 5 parallel groups studying RSVPreF3 (60 or 120 µg) coadministered with diphtheria, tetanus, and acellular pertussis vaccine (dTpa) or placebo, and dTpa coadministered with placebo. Safety and humoral immune responses were assessed. An extension phase also assessed a RSVPreF3 120 μg vaccination 12-18 months after first vaccination., Results: The safety profile of RSVPreF3 was unaffected by dose or dTpa coadministration. Solicited and unsolicited adverse events (AEs) were evenly distributed across study groups. Injection-site pain was higher following the second vaccination versus the first vaccination. Medically attended AEs were rare (<5% overall). Both RSVPreF3 dose levels (alone and with dTpa) were immunogenic, increasing levels of RSV-A neutralizing antibody ≥8-fold and anti-RSVPreF3 IgG antibody ≥11-fold at 1 month postvaccination, which persisted at 12-18 months postvaccination; modest 2-fold increases were observed with a second RSVPreF3 vaccination., Conclusions: This study indicates RSVPreF3 coadministration with dTpa induces robust immune responses and is well tolerated, regardless of the RSVPreF3 dose level used., Clinical Trials Registration: NCT04138056., Competing Interests: Potential conflicts of interest. N. He., D. Y., N. Hu., P. v. d. S., I. L., and J. H. K. are GSK employees. P. v. d. S., B. A., I. L., and J. H. K. receive GSK shares/stock options as part of their employee remuneration. M. F. received a salary as principal investigator for the Colchester Research Group which he co-owns with his wife, Dr Linda Ferguson, and which took part in this study. I. L.-R. received fees from GSK for conducting the present work; their institution has received grants from Virometix and Icosavax; and has received personal fees from Janssen for participating in an Advisory Board. S. P. has no potential conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

We previously reported that human muscle-derived stem cells (hMuStem cells) contribute to tissue repair after local administration into injured skeletal muscle or infarcted heart in immunodeficient rodent models. However, extrapolation of these findings to a clinical context is problematic owing to the considerable differences often seen between in vivo findings in humans versus rodents. Therefore, we investigated whether the muscle regenerative behavior of hMuStem cells is maintained in a clinically relevant transplantation context. Human MuStem cells were intramuscularly administered by high-density microinjection matrices into nonhuman primates receiving tacrolimus-based immunosuppression thereby reproducing the protocol that has so far produced the best results in clinical trials of cell therapy in myopathies. Four and 9 weeks after administration, histological analysis of cell injection sites revealed large numbers of hMuStem cell-derived nuclei in all cases. Most graft-derived nuclei were distributed in small myofiber groups in which no signs of a specific immune response were observed. Importantly, hMuStem cells contributed to simian tissue repair by fusing mainly with host myofibers, demonstrating their capacity for myofiber regeneration in this model. Together, these findings obtained in a valid preclinical model provide new insights supporting the potential of hMuStem cells in future cell therapies for muscle diseases., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Association of Neuropathologists, Inc. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: The adjuvanted RSV prefusion F protein-based vaccine (RSVPreF3 OA) was efficacious against RSV-related lower respiratory tract disease (RSV-LRTD) in ≥60-years-olds over 1 RSV season. We evaluated efficacy and safety of 1 RSVPreF3 OA dose and of 2 RSVPreF3 OA doses given 1 year apart against RSV-LRTD over 2 RSV seasons post-dose 1., Methods: In this phase 3, blinded trial, ≥60-year-olds were randomized (1:1) to receive RSVPreF3 OA or placebo pre-season 1. RSVPreF3 OA recipients were re-randomized (1:1) to receive a second RSVPreF3 OA dose (RSV&#95;revaccination group) or placebo (RSV&#95;1dose group) pre-season 2; participants who received placebo pre-season 1 received placebo pre-season 2 (placebo group). Efficacy of both vaccine regimens against RSV-LRTD was evaluated over 2 seasons combined (confirmatory secondary objective, success criterion: lower limits of 2-sided CIs around efficacy estimates >20%)., Results: The efficacy analysis comprised 24 967 participants (RSV&#95;1dose: 6227; RSV&#95;revaccination: 6242; placebo: 12 498). Median efficacy follow-up was 17.8 months. Efficacy over 2 seasons of 1 RSVPreF3 OA dose was 67.2% (97.5% CI: 48.2-80.0%) against RSV-LRTD and 78.8% (95% CI: 52.6-92.0%) against severe RSV-LRTD. Efficacy over 2 seasons of a first dose followed by revaccination was 67.1% (97.5% CI: 48.1-80.0%) against RSV-LRTD and 78.8% (95% CI: 52.5-92.0%) against severe RSV-LRTD. Reactogenicity/safety of the revaccination dose were similar to dose 1., Conclusions: One RSVPreF3 OA dose was efficacious against RSV-LRTD over 2 RSV seasons in ≥60-year-olds. Revaccination 1 year post-dose 1 was well tolerated but did not seem to provide additional efficacy benefit in the overall study population., Clinical Trials Registration: ClinicalTrials.gov: NCT04886596., Competing Interests: Potential conflicts of interest . M. G. I. declares that research support from GSK was paid to his previous institution, Northwestern University; he received consulting fees from Adagio Therapeutics, ADMA Biologics, Adamis Pharmaceuticals, AlloVir, Atea, Cidara Therapeutics, Genentech/Roche, Janssen, Shionogi, Takeda, Talaris, and Eurofins Viracor; and payment for participating in data safety monitoring boards or advisory boards from Adamis Pharmaceuticals, AlloVir, National Institutes of Health, CSL Behring, Janssen, Merck, Seqirus, Takeda, and Talaris; all of these ended in December 2022; M. G. I. also receives author royalties from UpToDate, which is ongoing, and serves as Chair of the International Society for Influenza and other Respiratory Virus Diseases Antiviral Group and was Editor-in-Chief of Transplant Infectious Disease. A. P. declares funding from GSK for conducting the trial. A. P. also declares that his institution received grants from Chiesi, AstraZeneca, GSK, Sanofi, and Agenzia Italiana del Farmaco; that he received consulting fees from Chiesi, AstraZeneca, GSK, Novartis, Sanofi, Avillion, and ELPEN Pharmaceuticals; payment for participation in advisory boards from Chiesi, AstraZeneca, GSK, Novartis, Sanofi, IQVIA, Avillion, and ELPEN Pharmaceuticals; and honoraria from Chiesi, AstraZeneca, GSK, Menarini, Novartis, Zambon, Mundipharma, Sanofi, Edmond Pharmaceuticals, IQVIA, Avillion, and ELPEN Pharmaceuticals. R. G. F. declares having received payment from GSK for lectures and support for travel related to these activities. J. M. L. reports grants from GSK paid to her institution for the conduct of the trial and from GSK, Pfizer, Merck, Moderna, Sanofi, Inventprise, and VBI Vaccines for other trials; J. M. L. also reports being a board member of Seqirus and participating on a data safety monitoring board or advisory board for Vaxcyte; she is an expert panelist for Canada's Drug and Health Technology Agency for the review of nirsevimab. I. L.-R. declares that her institution received funding from GSK for conducting this trial; from Icosavax, Virometix, Janssen Vaccines, Curevac, Moderna, Osivax, MSD, ICON Genetics, and OSE Immunotherapeutics for other vaccine trials; from Janssen Vaccines and MSD for consulting services; and from Janssen Vaccines for participation on a data safety monitoring board or advisory board. F. M.-T. declares that his institution received payment from GSK for conducting this trial and from Ablynx, Abbott, Seqirus, Sanofi, MSD, Merck, Pfizer, Roche, Regeneron, Janssen, Medimmune, Novavax, Novartis, and GSK for other vaccine trials; F. M.-T. also reports receiving honoraria for lectures from Sanofi, MSD, Moderna, GSK, Biofabri, AstraZeneca, Novavax, Janssen, and Pfizer; payment of travel expenses and meeting fees from Pfizer, MSD, GSK, and Sanofi; and participation on data safety monitoring boards or advisory boards for Pfizer and Biofabri; F. M.-T. is also a member of the World Health Organization’s (WHO's) European Technical Advisory Group of Experts, coordinator of the Spanish Pediatric Clinical Trials Network, and coordinator of the WHO Collaborating Center for Vaccine Safety of Santiago de Compostela. T. F. S. reports honoraria and/or participation on data safety monitoring boards or advisory boards from Alexion, AstraZeneca, Bavarian Nordic, Biogen, Biontech, GSK, Janssen-Cilag, Merck-Serono, Moderna, MSD, Novavax, Pfizer, Roche, Sanofi-Aventis, Seqirus, Synlab, Takeda, and va-Q-tec. R. N. v. Z.-S. reports that his institution received support from Boehringer Ingelheim for the Interstitial Lung Diseases (ILD) registry and that he received consulting fees from GSK and honoraria for lectures from Glenmark, Boehringer Ingelheim, Cipla, and Novartis; R. N. v. Z.-S. also participated on data safety monitoring boards or advisory boards for OnQ SA; he is president of the South African Thoracic Society and co-chair of the International Health Committee of the American Thoracic Society. C. V., N. D., O. G., L. F., M.-P. D., L. K., V. H., A. O., M. V. d. W., and D. D. are employed by GSK and have stock options or shares from GSK. N. D. is co-applicant on a pending patent for vaccination against RSV and has stock options from Haleon. L. F., M.-P. D., A. O., and M. V. d. W. are co-applicants on a pending patent filed by GSK. The other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Preclinical data acquired for human muscle stem (hMuStem) cells indicate their great repair capacity in the context of muscle injury. However, their clinical potential is limited by their moderate ability to survive after transplantation. To overcome these limitations, their encapsulation within protective environment would be beneficial. In this study, tunable calcium-alginate hydrogels obtained through molding method using external or internal gelation were investigated as a new strategy for hMuStem cell encapsulation. The mechanical properties of these hydrogels were characterized in their fully hydrated state by compression experiments using Atomic Force Microscopy. Measured elastic moduli strongly depended on the gelation mode and calcium/alginate concentrations. Values ranged from 1 to 12.5 kPa and 3.9 to 25 kPa were obtained for hydrogels prepared following internal and external gelation, respectively. Also, differences in mechanical properties of hydrogels resulted from their internal organization, with an isotropic structure for internal gelation, while external mode led to anisotropic one. It was further shown that viability, morphological and myogenic differentiation characteristics of hMuStem cells incorporated within alginate hydrogels were preserved after their release. These results highlight that hMuStem cells encapsulated in calcium-alginate hydrogels maintain their functionality, thus allowing to develop muscle regeneration protocols to improve their therapeutic efficacy., Competing Interests: Declaration of competing interest The authors declare no competing financial interests., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Colistin serves as the last line of defense against multidrug resistant Gram-negative bacterial infections in both human and veterinary medicine. This study aimed to investigate the occurrence and spread of colistin-resistant Enterobacterales (ColR-E) using a One Health approach in Belgium and in the Netherlands., Methods: In a transnational research project, a total of 998 hospitalized patients, 1430 long-term care facility (LTCF) residents, 947 children attending day care centres, 1597 pigs and 1691 broilers were sampled for the presence of ColR-E in 2017 and 2018, followed by a second round twelve months later for hospitalized patients and animals. Colistin treatment incidence in livestock farms was used to determine the association between colistin use and resistance. Selective cultures and colistin minimum inhibitory concentrations (MIC) were employed to identify ColR-E. A combination of short-read and long-read sequencing was utilized to investigate the molecular characteristics of 562 colistin-resistant isolates. Core genome multi-locus sequence typing (cgMLST) was applied to examine potential transmission events., Results: The presence of ColR-E was observed in all One Health sectors. In Dutch hospitalized patients, ColR-E proportions (11.3 and 11.8% in both measurements) were higher than in Belgian patients (4.4 and 7.9% in both measurements), while the occurrence of ColR-E in Belgian LTCF residents (10.2%) and children in day care centres (17.6%) was higher than in their Dutch counterparts (5.6% and 12.8%, respectively). Colistin use in pig farms was associated with the occurrence of colistin resistance. The percentage of pigs carrying ColR-E was 21.8 and 23.3% in Belgium and 14.6% and 8.9% in the Netherlands during both measurements. The proportion of broilers carrying ColR-E in the Netherlands (5.3 and 1.5%) was higher compared to Belgium (1.5 and 0.7%) in both measurements. mcr-harboring E. coli were detected in 17.4% (31/178) of the screened pigs from 7 Belgian pig farms. Concurrently, four human-related Enterobacter spp. isolates harbored mcr-9.1 and mcr-10 genes. The majority of colistin-resistant isolates (419/473, 88.6% E. coli; 126/166, 75.9% Klebsiella spp.; 50/75, 66.7% Enterobacter spp.) were susceptible to the critically important antibiotics (extended-spectrum cephalosporins, fluoroquinolones, carbapenems and aminoglycosides). Chromosomal colistin resistance mutations have been identified in globally prevalent high-risk clonal lineages, including E. coli ST131 (n = 17) and ST1193 (n = 4). Clonally related isolates were detected in different patients, healthy individuals and livestock animals of the same site suggesting local transmission. Clonal clustering of E. coli ST10 and K. pneumoniae ST45 was identified in different sites from both countries suggesting that these clones have the potential to spread colistin resistance through the human population or were acquired by exposure to a common (food) source. In pig farms, the continuous circulation of related isolates was observed over time. Inter-host transmission between humans and livestock animals was not detected., Conclusions: The findings of this study contribute to a broader understanding of ColR-E prevalence and the possible pathways of transmission, offering insights valuable to both academic research and public health policy development., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 De Koster et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: In the previous (parent) study, 2 doses of different formulations of an investigational vaccine against respiratory syncytial virus (RSVPreF3 OA) were well tolerated and immunogenic in older adults. This multicenter phase 2b extension study assessed safety and immunogenicity of a revaccination (third) dose of the 120 μg RSVPreF3-AS01E formulation., Methods: In total, 122 older adults (60-80 years), previously vaccinated with 2 doses of RSVPreF3-AS01E formulations (containing 30, 60, or 120 μg RSVPreF3 antigen), received an additional 120 μg RSVPreF3-AS01E dose 18 months after dose 2. Vaccine safety was evaluated in all participants up to 6 months and immunogenicity in participants who received 120 μg RSVPreF3-AS01E doses until 1 month after dose 3., Results: Similar to the parent study, mostly mild-to-moderate solicited adverse events and no vaccine-related serious adverse events or potential immune-mediated disorders were reported. Neutralizing titers and cell-mediated immune responses persisted for 18 months after 2-dose vaccination. Dose 3 increased RSV-specific neutralizing titers against RSV-A and RSV-B and median CD4+ T-cell frequencies. After dose 3, RSV-specific neutralizing titers but not CD4+ T-cell frequencies were below levels detected 1 month after dose 1., Conclusions: Revaccination with 120 μg RSVPreF3-AS01E 18 months after dose 2 is well tolerated and immunogenic in older adults., Clinical Trials Registration: NCT04657198; EudraCT, 2020-000692-21., Competing Interests: Potential conflicts of interest. I. L. R. reports funding from Icosavax and Virometix to her institution for the conduct of RSV vaccine trials, and from GSK to her institution for conduct of this clinical trial. M. V. R. reports GSK funding to the Leuven University Vaccinology Center for the conduct of the clinical trial. C. Vm. reports GSK funding to her institution for the conduct of the clinical trial as at the time of the execution of the clinical trial she was an investigator; C. Vm. joined GSK after the close of the study at her institution and is currently an employee of GSK; however, she does not hold any shares. C. V. A., N. D. S., B. S., C. V., M. P. D., S. K., and V. H. were employees of GSK at the time of the study conduct. N. D. S., B. S., M. P. D., C. V., S. K., and V. H. hold shares from GSK as part of their past/current employee remuneration. All current/previous employees of GSK declare financial and nonfinancial relationships and activities. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

This study aimed to map MDRO carriage and potential transmission within and between three Flemish tertiary care hospitals and their neighbouring nursing homes. A cross-sectional MDRO prevalence survey was organized between October 2017 and February 2019. Perianal swabs were cultured for detection of MDRO. Determination of clonal relatedness based on wgMLST allelic profiles was performed. The prevalence of MDRO in Belgian hospitals and NHs is on the rise, compared to previous studies, and transmission in and between institutions is observed. These results re-emphasize the need for a healthcare network-wide infection prevention strategy in which WGS of MDRO strains can be supportive., (© 2023. The Author(s).)

Background: OVX836, a recombinant vaccine containing the nucleoprotein of the influenza A virus A/WSN/1933 (H1N1) and the oligomerisation domain OVX313, has displayed a good safety profile and elicited dose-dependent humoral and cellular immune responses at 90 μg or 180 μg (intramuscularly) in previous clinical trials. The aim of this study was to explore higher doses, since no maximum tolerated dose had been reached., Methods: In this phase 2a, randomised, double-blind, placebo-controlled study, we recruited 137 healthy adults aged 18-55 years in a single centre in Belgium. Participants were randomly assigned (interactive web response system; block size=4) using SAS (version 9.4) to receive one single intramuscular administration of OVX836 influenza vaccine at three doses (180 μg [n=33], 300 μg [n=35], and 480 μg [n=36]) or placebo (n=33). The two primary endpoints were the safety and the cell-mediated immune response to OVX836 at the three doses in terms of change of nucleoprotein-specific IFNγ spot forming cell (SFC) frequencies in the peripheral blood mononuclear cell (PBMC) population, measured by IFNγ ELISpot, at day 8 versus pre-injection baseline (day 1). The population used for the safety analysis is the modified intention-to-treat cohort. The population used for the immunogenicity analysis is the per-protocol cohort. This trial is registered with ClinicalTrials.gov, NCT05060887, and EudraCT, 2021-002535-39., Findings: Participants were recruited between Nov 15, 2021, and Feb 1, 2022. OVX836 had a favourable safety profile up to 480 μg without reaching the maximum tolerated dose, and showed a good safety profile at all doses with mild local and systemic reactogenicity. 7 days after vaccination, although no significant differences were observed between the doses, OVX836 increased the frequency of nucleoprotein-specific IFNγ SFCs per million PBMCs from days 1 to 8 (primary endpoint): by 124 SFCs per 10 6 PMBCs (95% CI 67 to 180; p=0·002) at 180 μg; by 202 SFCs per 10 6 PMBCs (95% CI 138 to 267; p<0·0001) at 300 μg; by 223 SFCs per 10 6 PMBCs (95% CI 147 to 299; p<0·0001) at 480 μg; and decreased by 1 SFCs per 10 6 PMBCs (95% CI -24 to 22] in the placebo group (Kruskal-Wallis test p<0·0001 followed by Mann-Whitney's tests; per-protocol cohort). Dose-dependent and polyfunctional nucleoprotein-specific CD4 T-cell responses were observed, and CD8 T-cell responses were elicited at 300 μg and 480 μg (secondary endpoints)., Interpretation: OVX836 appears to be a safe and well tolerated candidate vaccine that elicits humoral and cellular nucleoprotein-specific immune responses (including CD8 T cells at the highest dose levels) and showed a preliminary signal of protection against influenza. Therefore, OVX836 is a promising vaccine candidate for universal influenza A prevention, that warrants further trials., Funding: OSIVAX, Bpifrance, Wallonia Region, and the EUs Horizon 2020 Research and Innovation Program., Competing Interests: Declaration of interests JT, FN, and ALV are employees and shareholders of OSIVAX. PW, JB, and GL-R received consulting honoraria from OSIVAX. IL-R, GW, YJ, FDB, AA, and BJ, who are all working at CEVAC Clinical Unit or Laboratory, have been funded by OSIVAX. In the past 36 months, IL-R has been funded by GSK Biologicals and Litevax for other studies on influenza vaccines., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Lyme borreliosis, potentially associated with serious long-term complications, is caused by the species complex Borrelia burgdorferi sensu lato. We investigated a novel Lyme borreliosis vaccine candidate (VLA15) targeting the six most common outer surface protein A (OspA) serotypes 1-6 to prevent infection with pathogenic Borrelia spp prevalent in Europe and North America., Methods: This was a partially randomised, observer-masked, phase 1 study in healthy adults older than 18 years to younger than 40 years (n=179) done in trial sites in Belgium and the USA. Following a non-randomised run-in phase, a sealed envelope randomisation method was applied with a 1:1:1:1:1:1 ratio; three dose concentrations of VLA15 (12 μg, 48 μg, and 90 μg) were administered by intramuscular injection on days 1, 29, and 57. The primary outcome was safety (frequency of adverse events up to day 85) assessed in participants who received at least one vaccination. Immunogenicity was a secondary outcome. The trial is registered with ClinicalTrials.gov, NCT03010228, and is complete., Findings: Between Jan 23, 2017 and Jan 16, 2019, of 254 participants screened for eligibility, 179 were randomly assigned into six groups: alum-adjuvanted 12 μg (n=29), 48 μg (n=31), or 90 μg (n=31) and non-adjuvanted 12 μg (n=29 participants), 48 μg (n=29), or 90 μg (n=30). VLA15 was safe and well tolerated and the majority of adverse events were mild or moderate. Overall, adverse events were more frequent in the 48 μg and 90 μg groups (range 28-30 participants [94-97%]) when compared with the 12 μg group (25 [86%] participants, 95% CI 69·4-94·5) for adjuvanted and non-adjuvanted groups. Common local reactions were tenderness (151 [84%] participants; 356 events, 95% CI 78·3-89·4) and injection site pain (120 [67%]; 224 events, 59·9-73·5); most frequent systemic reactions were headache (80 [45%]; 112 events, 37·6-52·0), excessive fatigue (45 [25%]; 56 events, 19·4-32·0), and myalgia (45 [25%]; 57 events, 19·4-32·0). A similar safety and tolerability profile was observed between adjuvanted and non-adjuvanted formulations. The majority of solicited adverse events were mild or moderate. VLA15 was immunogenic for all OspA serotypes with higher immune responses induced in the adjuvanted higher dose groups (geometric mean titre range 90 μg with alum 61·3 U/mL-321·7 U/mL vs 23·8 U/mL-111·5 U/mL at 90 μg without alum)., Interpretation: This novel multivalent vaccine candidate against Lyme borreliosis was safe and immunogenic and paves the way to further clinical development., Funding: Valneva Austria., Competing Interests: Declaration of interests IL-R reports funding from Valneva to her institution for the conduct of this study. In addition, she received funding to her institution from several industry partners for the conduct of various vaccine trials, but none of them in the area of Lyme borreliosis. NB, RH, VK, NW, KD, SE-L, and WB are Valneva employees and own stock and share options in Valneva. AK, JL-S, and GL-R declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Dystrophic muscle is characterized by necrosis/regeneration cycles, inflammation, and fibro-adipogenic development. Conventional histological stainings provide essential topographical data of this remodeling but may be limited to discriminate closely related pathophysiological contexts. They fail to mention microarchitecture changes linked to the nature and spatial distribution of tissue compartment components. We investigated whether label-free tissue autofluorescence revealed by Synchrotron deep ultraviolet (DUV) radiation could serve as an additional tool for monitoring dystrophic muscle remodeling. Using widefield microscopy with specific emission fluorescence filters and microspectroscopy defined by high spectral resolution, we analyzed samples from healthy dogs and two groups of dystrophic dogs: naïve (severely affected) and MuStem cell-transplanted (clinically stabilized) animals. Multivariate statistical analysis and machine learning approaches demonstrated that autofluorescence emitted at 420-480 nm by the Biceps femoris muscle effectively discriminates between healthy, dystrophic, and transplanted dog samples. Microspectroscopy showed that dystrophic dog muscle displays higher and lower autofluorescence due to collagen cross-linking and NADH respectively than that of healthy and transplanted dogs, defining biomarkers to evaluate the impact of cell transplantation. Our findings demonstrate that DUV radiation is a sensitive, label-free method to assess the histopathological status of dystrophic muscle using small amounts of tissue, with potential applications in regenerative medicine., (© 2023. The Author(s).)

The development of an efficacious vaccine against norovirus is of paramount importance given its potential to reduce the global burden of norovirus-associated morbidity and mortality. Here, we report a detailed immunological analysis of a phase I, double-blind, placebo-controlled clinical trial performed on 60 healthy adults, ages 18 to 40. Total serum immunoglobulin and serum IgA against vaccine strains and cross-reactive serum IgG against non-vaccine strains were measured by enzyme immunoassays, whereas cell-mediated immune responses were quantified using intracellular cytokine staining by flow cytometry. A significant increase in humoral and cellular responses, e.g., IgA and CD4 + polypositive T cells, was triggered by the GI.4 Chiba 407 (1987) and GII.4 Aomori 2 (2006) VLP-based norovirus vaccine candidate rNV-2v, which is formulated without adjuvant. No booster effect was observed after the second administration in the pre-exposed adult study population. Furthermore, a cross-reactive immune response was elicited, as shown by IgG titers against GI.3 (2002), GII.2 OC08154 (2008), GII.4 (1999), GII.4 Sydney (2012), GII.4 Washington (2018), GII.6 Maryland (2018), and GII.17 Kawasaki 308 (2015). Due to viral infection via mucosal gut tissue and the high variety of potentially relevant norovirus strains, a focus should be on IgA and cross-protective humoral and cell-mediated responses in the development of a broadly protective, multi-valent norovirus vaccine., Clinical Trial Registration: https://clinicaltrials.gov, identifier NCT05508178. EudraCT number: 2019-003226-25., Competing Interests: Author GL-R acts as a consultant for Icon Genetics GmbH (Halle, Germany) to assist in the design and management of the trial, analysis of results, and development of the manuscript. AD, FJ, VK, and FT are employees of Icon Genetics GmbH (Halle, Germany), a wholly owned subsidiary of Denka Company, Ltd. (Tokyo, Japan). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The authors declare that this trial has received funding from Icon Genetics GmbH (Halle, Germany), a wholly owned subsidiary of Denka Ltd. (Tokyo, Japan). The funder was involved in the study design, analysis and interpretation of data, the writing of this article, and the decision to submit it for publication., (Copyright © 2023 Waerlop, Janssens, Jacobs, Jarczowski, Diessner, Leroux-Roels, Klimyuk, Leroux-Roels and Thieme.)

Background: Accumulating evidence shows a role of the hospital wastewater system in the spread of multidrug-resistant organisms, such as carbapenemase producing Enterobacterales (CPE). Several sequential outbreaks of CPE on the geriatric ward of the Ghent University hospital have led to an outbreak investigation. Focusing on OXA-48 producing Citrobacter freundii, the most prevalent species, we aimed to track clonal relatedness using whole genome sequencing (WGS). By exploring transmission routes we wanted to improve understanding and (re)introduce targeted preventive measures., Methods: Environmental screening (toilet water, sink and shower drains) was performed between 2017 and 2021. A retrospective selection was made of 53 Citrobacter freundii screening isolates (30 patients and 23 environmental samples). DNA from frozen bacterial isolates was extracted and prepped for shotgun WGS. Core genome multilocus sequence typing was performed with an in-house developed scheme using 3,004 loci., Results: The CPE positivity rate of environmental screening samples was 19.0% (73/385). Highest percentages were found in the shower drain samples (38.2%) and the toilet water samples (25.0%). Sink drain samples showed least CPE positivity (3.3%). The WGS data revealed long-term co-existence of three patient sample derived C. freundii clusters. The biggest cluster (ST22) connects 12 patients and 8 environmental isolates taken between 2018 and 2021 spread across the ward. In an overlapping period, another cluster (ST170) links eight patients and four toilet water isolates connected to the same room. The third C. freundii cluster (ST421) connects two patients hospitalised in the same room but over a period of one and a half year. Additional sampling in 2022 revealed clonal isolates linked to the two largest clusters (ST22, ST170) in the wastewater collection pipes connecting the rooms., Conclusions: Our findings suggest long-term circulation and transmission of carbapenemase producing C. freundii clones in hospital sanitary installations despite surveillance, daily cleaning and intermittent disinfection protocols. We propose a role for the wastewater drainage system in the spread within and between rooms and for the sanitary installations in the indirect transmission via bioaerosol plumes. To tackle this problem, a multidisciplinary approach is necessary including careful design and maintenance of the plumbing system., (© 2023. The Author(s).)