A palaeogenomic investigation of overharvest implications in an endemic wild reindeer subspecies.

Overharvest can severely reduce the abundance and distribution of a species and thereby impact its genetic diversity and threaten its future viability. Overharvest remains an ongoing issue for Arctic mammals, which due to climate change now also confront one of the fastest changing environments on Earth. The high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus), endemic to Svalbard, experienced a harvest-induced demographic bottleneck that occurred during the 17-20th centuries. Here, we investigate changes in genetic diversity, population structure, and gene-specific differentiation during and after this overharvesting event. Using whole-genome shotgun sequencing, we generated the first ancient and historical nuclear (n = 11) and mitochondrial (n = 18) genomes from Svalbard reindeer (up to 4000 BP) and integrated these data with a large collection of modern genome sequences (n = 90) to infer temporal changes. We show that hunting resulted in major genetic changes and restructuring in reindeer populations. Near-extirpation followed by pronounced genetic drift has altered the allele frequencies of important genes contributing to diverse biological functions. Median heterozygosity was reduced by 26%, while the mitochondrial genetic diversity was reduced only to a limited extent, likely due to already low pre-harvest diversity and a complex post-harvest recolonization process. Such genomic erosion and genetic isolation of populations due to past anthropogenic disturbance will likely play a major role in metapopulation dynamics (i.e., extirpation, recolonization) under further climate change. Our results from a high-arctic case study therefore emphasize the need to understand the long-term interplay of past, current, and future stressors in wildlife conservation.

Harvesting can stabilise population fluctuations and buffer the impacts of extreme climatic events.

Harvesting can magnify the destabilising effects of environmental perturbations on population dynamics and, thereby, increase extinction risk. However, population-dynamic theory predicts that impacts of harvesting depend on the type and strength of density-dependent regulation. Here, we used logistic population growth models and an empirical reindeer case study to show that low to moderate harvesting can actually buffer populations against environmental perturbations. This occurs because of density-dependent environmental stochasticity, where negative environmental impacts on vital rates are amplified at high population density due to intra-specific resource competition. Simulations from our population models show that even low levels of harvesting may prevent overabundance, thereby dampening population fluctuations and reducing the risk of population collapse and quasi-extinction following environmental perturbations. Thus, depending on the species' life history and the strength of density-dependent environmental drivers, low to moderate harvesting can improve population resistance to increased climate variability and extreme weather expected under global warming.

PFKFB3 gene deletion in endothelial cells inhibits intraplaque angiogenesis and lesion formation in a murine model of venous bypass grafting.

Vein grafting is a frequently used surgical intervention for cardiac revascularization. However, vein grafts display regions with intraplaque (IP) angiogenesis, which promotes atherogenesis and formation of unstable plaques. Graft neovessels are mainly composed of endothelial cells (ECs) that largely depend on glycolysis for migration and proliferation. In the present study, we aimed to investigate whether loss of the glycolytic flux enzyme phosphofructokinase-2/fructose-2,6-bisphosphatase 3 (PFKFB3) in ECs inhibits IP angiogenesis and as such prevents unstable plaque formation. To this end, apolipoprotein E deficient (ApoE-/-) mice were backcrossed to a previously generated PFKFB3fl/fl Cdh5iCre mouse strain. Animals were injected with either corn oil (ApoE-/-PFKFB3fl/fl) or tamoxifen (ApoE-/-PFKFB3ECKO), and were fed a western-type diet for 4 weeks prior to vein grafting. Hereafter, mice received a western diet for an additional 28 days and were then sacrificed for graft assessment. Size and thickness of vein graft lesions decreased by 35 and 32%, respectively, in ApoE-/-PFKFB3ECKO mice compared to controls, while stenosis diminished by 23%. Moreover, vein graft lesions in ApoE-/-PFKFB3ECKO mice showed a significant reduction in macrophage infiltration (29%), number of neovessels (62%), and hemorrhages (86%). EC-specific PFKFB3 deletion did not show obvious adverse effects or changes in general metabolism. Interestingly, RT-PCR showed an increased M2 macrophage signature in vein grafts from ApoE-/-PFKFB3ECKO mice. Altogether, EC-specific PFKFB3 gene deletion leads to a significant reduction in lesion size, IP angiogenesis, and hemorrhagic complications in vein grafts. This study demonstrates that inhibition of endothelial glycolysis is a promising therapeutic strategy to slow down plaque progression.

The evolving personal, professional and physical impact on healthcare professionals during three COVID-19 waves: A cross-sectional study.

BACKGROUND: The COVID-19 pandemic has led to huge pressure on not only healthcare systems, but also on healthcare professionals. OBJECTIVE: As the pandemic continues, the aim of this study is to evaluate how 10 reactions of healthcare professionals evolved during the first 18 months of COVID-19. METHODS: A repeated cross-sectional study was performed with eight measurement points between April 2020 and September 2021 in Belgium. Participants were asked how frequently (on a scale of 0-10) they experienced positive and negative reactions during normal circumstances and during past week, referred to as before and during COVID-19, respectively. These reactions were stress, fatigue, difficulty sleeping, muscle strain, hypervigilance, leaving profession, headache, doubting knowledge and skills, flashbacks and fear. RESULTS: In total, 13 308 respondents were included in our study. During both the first (March 2020) and second COVID-19 peak (November 2020), the measured personal, professional and physical reactions were significantly higher compared to before COVID-19. The third wave in April 2021 was shorter and less severe with regard to hospital admissions and deaths, yet an important impact on healthcare professionals could still be observed. 'Fatigue,' 'stress,' 'difficulty sleeping' and 'muscle strain' are the most worrying reactions in September 2021, which are increasing compared to the previous measurements. CONCLUSION: Our results showed that acute stress reactions decreased over time but that chronic stress reactions and professional reactions, such as 'intent to leave,' increased. Healthcare organizations and policy makers should realize that 18 months after the start of COVID-19 almost all of the measured reactions continue to be more prevalent than before COVID-19. Moreover, the continuous increase over the last three measurement periods of the number of healthcare professionals who want to leave their profession is alarming. Continuous follow-up of the personal, professional and physical reactions is more than necessary.

Sea ice loss increases genetic isolation in a high Arctic ungulate metapopulation.

Sea ice loss may have dramatic consequences for population connectivity, extinction-colonization dynamics, and even the persistence of Arctic species subject to climate change. This is of particular concern in face of additional anthropogenic stressors, such as overexploitation. In this study, we assess the population-genetic implications of diminishing sea ice cover in the endemic, high Arctic Svalbard reindeer (Rangifer tarandus platyrhynchus) by analyzing the interactive effects of landscape barriers and reintroductions (following harvest-induced extirpations) on their metapopulation genetic structure. We genotyped 411 wild reindeer from 25 sampling sites throughout the entire subspecies' range at 19 microsatellite loci. Bayesian clustering analysis showed a genetic structure composed of eight populations, of which two were admixed. Overall population genetic differentiation was high (mean FST  = 0.21). Genetic diversity was low (allelic richness [AR] = 2.07-2.58; observed heterozygosity = 0.23-0.43) and declined toward the outer distribution range, where populations showed significant levels of inbreeding. Coalescent estimates of effective population sizes and migration rates revealed strong evolutionary source-sink dynamics with the central population as the main source. The population genetic structure was best explained by a landscape genetics model combining strong isolation by glaciers and open water, and high connectivity by dispersal across winter sea ice. However, the observed patterns of natural isolation were strongly modified by the signature of past harvest-induced extirpations, subsequent reintroductions, and recent lack of sea ice. These results suggest that past and current anthropogenic drivers of metapopulation dynamics may have interactive effects on large-scale ecological and evolutionary processes. Continued loss of sea ice as a dispersal corridor within and between island systems is expected to increase the genetic isolation of populations, and thus threaten the evolutionary potential and persistence of Arctic wildlife.

Performance of three automated SARS-CoV-2 antibody assays and relevance of orthogonal testing algorithms.

Objectives: Development and implementation of SARS-CoV-2 serologic assays gained momentum. Laboratories keep on investigating the performance of these assays. In this study, we compared three fully automated SARS-CoV-2 antibody assays. Methods: A total of 186 samples from 84 PCR-positive COVID-19 patients and 120 control samples taken before the SARS-CoV-2 pandemic were analyzed using commercial serologic assays from Roche, Siemens and DiaSorin. Time after the positive COVID-19 PCR result and onset of symptoms was retrieved from the medical record. An extended golden standard, using the result of all three assays was defined, judging if antibodies are present or absent in a sample. Diagnostic and screening sensitivity/specificity and positive/negative predictive value were calculated. Results: Diagnostic sensitivity (ability to detect a COVID-19 positive patient) ≥14 days after positive PCR testing was 96.7% (95% CI 88.5-99.6%) for DiaSorin, 93.3% (95% CI 83.8-98.2%) for Roche and 100% (95% CI 94.0-100%) for Siemens. Lower diagnostic sensitivities were observed <14 days after onset of symptoms for all three assay. Diagnostic specificity (ability to detect a COVID-19 negative patient) was 95.0% (95% CI 89.4-98.1%) for DiaSorin, 99.2% (95% CI 95.4-99.9%) for Roche and 100% (95% CI 97.0-100%) for Siemens. The sensitivity/specificity for detecting antibodies (ability of detecting absence (specificity) or presence (sensitivity) of COVID-19 antibodies) was 92.4% (95% CI 86.4-96.3%)/94.9% (95% CI 90.5-97.6%) for DiaSorin, 97.7% (95% CI 93.5-99.5%)/97.1% (95% CI 93.5-99.1%) for Roche and 98.5% (95% CI 94.6-99.8)/97.1 (95% CI 93.5-99.1%) for Siemens. Conclusions: This study revealed acceptable performance for all three assays. An orthogonal testing algorithm using the Siemens and Roche assay achieved the highest positive predictive values for antibody detection in low seroprevalence settings.

Spatial heterogeneity in climate change effects decouples the long-term dynamics of wild reindeer populations in the high Arctic.

The 'Moran effect' predicts that dynamics of populations of a species are synchronized over similar distances as their environmental drivers. Strong population synchrony reduces species viability, but spatial heterogeneity in density dependence, the environment, or its ecological responses may decouple dynamics in space, preventing extinctions. How such heterogeneity buffers impacts of global change on large-scale population dynamics is not well studied. Here, we show that spatially autocorrelated fluctuations in annual winter weather synchronize wild reindeer dynamics across high-Arctic Svalbard, while, paradoxically, spatial variation in winter climate trends contribute to diverging local population trajectories. Warmer summers have improved the carrying capacity and apparently led to increased total reindeer abundance. However, fluctuations in population size seem mainly driven by negative effects of stochastic winter rain-on-snow (ROS) events causing icing, with strongest effects at high densities. Count data for 10 reindeer populations 8-324 km apart suggested that density-dependent ROS effects contributed to synchrony in population dynamics, mainly through spatially autocorrelated mortality. By comparing one coastal and one 'continental' reindeer population over four decades, we show that locally contrasting abundance trends can arise from spatial differences in climate change and responses to weather. The coastal population experienced a larger increase in ROS, and a stronger density-dependent ROS effect on population growth rates, than the continental population. In contrast, the latter experienced stronger summer warming and showed the strongest positive response to summer temperatures. Accordingly, contrasting net effects of a recent climate regime shift-with increased ROS and harsher winters, yet higher summer temperatures and improved carrying capacity-led to negative and positive abundance trends in the coastal and continental population respectively. Thus, synchronized population fluctuations by climatic drivers can be buffered by spatial heterogeneity in the same drivers, as well as in the ecological responses, averaging out climate change effects at larger spatial scales.

Analytical performance of an automated volumetric flow cytometer for quantitation of T, B and natural killer lymphocytes.

BACKGROUND: Quantitation of lymphocyte subsets (B cells, T cells, CD4 and CD8 T cells and NK cells) classically relies on quantitation of lymphocytes and immunophenotyping by flow cytometry. AQUIOS CL (Beckman Coulter) is a fully automated system that performs an onboard volumetric cell count, automatically processes the sample (staining, lysing and fixation) and analyzes the results. We compared AQUIOS CL to a dual-platform analysis and evaluated analytical performance. METHODS: We evaluated precision, sample stability, inter-sample carryover, linearity and interpanel consistency. AQUIOS CL was compared to a dual-platform method (Sysmex XE-5000 and BD FACSCanto-II). A total of 113 patient samples were included: 45 from posttransplant patients, 44 from children and 24 random routine samples. The degree of automation was scored through the need of manual revisions triggered by AQUIOS CL run notifications and run flags. RESULTS: Intrarun and interrun variability was <9.1% with dedicated control material and <32.1% with patient samples. Relative values of lymphocyte subsets could be determined up to 48 h after venipuncture when the sample was kept at room temperature. There was no carryover and good linearity. Interpanel consistency was 3.3% for relative values and 9.4% for absolute values. Method comparison showed good analytical correlation between AQUIOS CL and a dual-platform method. Thirty-five percent of the samples triggered a run notification. In 74% of these samples, the results could be accepted without intervention, so in 26% of all samples, an unnecessary notification was generated. CONCLUSIONS: AQUIOS CL allows for reliable fully automated immunophenotyping of lymphocyte subset quantitation. Gating algorithms could be further improved.

Comparison of PCR-Electrospray Ionization Mass Spectrometry with 16S rRNA PCR and Amplicon Sequencing for Detection of Bacteria in Excised Heart Valves.

Identification of the causative pathogen of infective endocarditis (IE) is crucial for adequate management and therapy. A broad-range PCR-electrospray ionization mass spectrometry (PCR-ESI-MS) technique was compared with broad-spectrum 16S rRNA PCR and amplicon sequencing (16S rRNA PCR) for the detection of bacterial pathogens in 40 heart valves obtained from 34 definite infective endocarditis patients according to the modified Duke criteria and six nonendocarditis patients. Concordance between the two molecular techniques was 98% for being positive or negative, 97% for concordant identification up to the genus level, and 77% for concordant identification up to the species level. Sensitivity for detecting the causative pathogen (up to the genus level) in excised heart valves was 88% for 16S rRNA PCR and 85% for PCR-ESI-MS; the specificity was 83% for both methods. The two molecular techniques were significantly more sensitive than valve culture (18%) and accurately identified bacteria in excised heart valves. In eight patients with culture-negative IE, the following results were obtained: concordant detection of Coxiella burnetii (n = 2), Streptococcus gallolyticus (n = 1), Propionibacterium acnes (n = 1), and viridans group streptococci (n = 1) by both molecular tests, detection of P. acnes by PCR-ESI-MS whereas the 16S rRNA PCR was negative (n = 1), and a false-negative result by both molecular techniques (n = 2). In one case of IE caused by viridans streptococci, PCR-ESI-MS was positive for Enterococcus spp. The advantages of PCR-ESI-MS compared to 16S rRNA PCR are its automated workflow and shorter turnaround times.

Post-test probability for neonatal hyperbilirubinemia based on umbilical cord blood bilirubin, direct antiglobulin test, and ABO compatibility results.

UNLABELLED: Many hospitals opt for early postnatal discharge of newborns with a potential risk of readmission for neonatal hyperbilirubinemia. Assays/algorithms with the possibility to improve prediction of significant neonatal hyperbilirubinemia are needed to optimize screening protocols and safe discharge of neonates. This study investigated the predictive value of umbilical cord blood (UCB) testing for significant hyperbilirubinemia. Neonatal UCB bilirubin, UCB direct antiglobulin test (DAT), and blood group were determined, as well as the maternal blood group and the red blood cell antibody status. Moreover, in newborns with clinically apparent jaundice after visual assessment, plasma total bilirubin (TB) was measured. Clinical factors positively associated with UCB bilirubin were ABO incompatibility, positive DAT, presence of maternal red cell antibodies, alarming visual assessment and significant hyperbilirubinemia in the first 6 days of life. UCB bilirubin performed clinically well with an area under the receiver-operating characteristic curve (AUC) of 0.82 (95 % CI 0.80-0.84). The combined UCB bilirubin, DAT, and blood group analysis outperformed results of these parameters considered separately to detect significant hyperbilirubinemia and correlated exponentially with hyperbilirubinemia post-test probability. CONCLUSION: Post-test probabilities for neonatal hyperbilirubinemia can be calculated using exponential functions defined by UCB bilirubin, DAT, and ABO compatibility results. WHAT IS KNOWN: • The diagnostic value of the triad umbilical cord blood bilirubin measurement, direct antiglobulin testing and blood group analysis for neonatal hyperbilirubinemia remains unclear in literature. • Currently no guideline recommends screening for hyperbilirubinemia using umbilical cord blood. What is New: • Post-test probability for hyperbilirubinemia correlated exponentially with umbilical cord blood bilirubin in different risk groups defined by direct antiglobulin test and ABO blood group compatibility results. • Exponential functions can be used to calculate hyperbilirubinemia probability.

Understanding medication adherence among patients of Turkish descent with type 2 diabetes: a qualitative study.

OBJECTIVES: To explore perspectives of Turkish migrants with type 2 diabetes mellitus (T2DM) on adherence to oral hypoglycaemic agents (OHA). DESIGN: In-depth interviews with 21 T2DM patients of Turkish descent recruited from primary care and community sources in Ghent, Belgium, using a theoretical sampling procedure. Analysis was guided by a grounded theory approach, using Nvivo 8. RESULTS: Respondents reported a multitude of barriers and facilitators of adherence to OHA. Some of these barriers are distinctive for T2DM patients of Turkish descent. Respondents' causal beliefs about stress and the Belgian climate often led to non-adherence during less stressful periods, like summer holidays in Turkey. Some respondents adjusted their medication use to food intake or during Ramadan fasting. Concerns about OHA were the main reason for the widespread use of herbal medicine in this sample. The religious framework used to interpret diabetes led, in combination with feelings of depression, to non-adherence in some respondents while it facilitated medication adherence in others. A potential gender effect with respect to the self-management of OHA was observed. Non-distinctive factors include: beliefs about OHA, polypharmacy, beliefs about the course of diabetes, forgetfulness, the perception of the doctor's medical expertise, feelings of depression and social support. CONCLUSION: Health care providers should explore in detail and regularly patients' perspectives on illness beliefs, medication beliefs and their trust in doctors' medical expertise as this will provide useful starting points for promoting medication adherence. Whenever possible health care workers should engage with their patients in therapeutic alliances.

The integration of oral health care into day-to-day care in nursing homes: a qualitative study.

OBJECTIVE: This qualitative study explored barriers and enabling factors to the implementation of an oral hygiene protocol in nursing homes. BACKGROUND: Oral health care in nursing homes in Flanders (Belgium) is inadequate. MATERIALS AND METHODS: Qualitative data were obtained from nurses employed in 13 nursing homes involved in two randomised controlled trials in Flanders-Belgium. Data were collected by focus group and face-to-face interviews during April 2005 and December 2009. All transcripts were analysed with support of NVivo 8 (Version 2008). Transcripts were intuitively analysed in a two-step method. RESULTS: Most revealed barriers were consistent with previous findings in the literature. Newly reported barriers were respect for residents' self-determination, experience based oral health care by nurses, residents' oral health status and nurses' inability to notice residents' oral health status. Demand-driven oral health care was found to be a strong enabling factor. CONCLUSION: The integration of oral health care into day-to-day care seems to be a major problem due to a multitude of barriers. In future implementation innovations in oral health care an a priori assessment of influencing factors is recommended.

A high-resolution large-area detector for quality assurance in radiotherapy.

Hadron therapy is an advanced radiation modality for treating cancer, which currently uses protons and carbon ions. Hadrons allow for a highly conformal dose distribution to the tumour, minimising the detrimental side-effects due to radiation received by healthy tissues. Treatment with hadrons requires sub-millimetre spatial resolution and high dosimetric accuracy. This paper discusses the design, fabrication and performance tests of a detector based on Gas Electron Multipliers (GEM) coupled to a matrix of thin-film transistors (TFT), with an active area of 60 × 80 mm2 and 200 ppi resolution. The experimental results show that this novel detector is able to detect low-energy (40 kVp X-rays), high-energy (6 MeV) photons used in conventional radiation therapy and protons and carbon ions of clinical energies used in hadron therapy. The GEM-TFT is a compact, fully scalable, radiation-hard detector that measures secondary electrons produced by the GEMs with sub-millimetre spatial resolution and a linear response for proton currents from 18 pA to 0.7 nA. Correcting known detector defects may aid in future studies on dose uniformity, LET dependence, and different gas mixture evaluation, improving the accuracy of QA in radiotherapy.

Analytical performance and user-friendliness of four commercially available point-of-care devices for C-reactive protein.

INTRODUCTION: Proper implementation of Point-of-Care testing (POCT) for C-reactive protein (CRP) in primary care can decrease the inappropriate use of antibiotics, thereby tackling the problem of growing antimicrobial resistance. OBJECTIVE: The analytical performance and user-friendliness of four POCT-CRP assays were evaluated: QuikRead go easy, LumiraDx, cobas b 101 and Afinion 2. MATERIALS AND METHODS: Imprecision was evaluated using plasma pools in addition to manufacturer-specific control material. Trueness was assessed by verification of traceability to ERM-DA474/IFCC in parallel to method comparison towards the central laboratory CRP method (cobas c 503) using i) retrospectively selected plasma samples (n = 100) and ii) prospectively collected capillary whole blood samples (n = 50). User-friendliness was examined using a questionnaire. RESULTS: Between-day imprecision on plasma pools varied from 4.5 % (LumiraDx) to 11.5 % (QuikRead). Traceability verification revealed no significant difference between cobas c 503 CRP results and the ERM-DA474/IFCC certified value. cobas b 101 and Afinion achieved the best agreement with the central laboratory method. LumiraDx and QuikRead revealed a negative mean difference, with LumiraDx violating the criterion of > 95 % of POCT-CRP-results within ± 20 % of the comparison method. Regarding user-friendliness, Afinion obtained the highest Likert-scores. CONCLUSION: The analytical performance and user-friendliness of POCT-CRP devices varies among manufacturers, emphasizing the need for quality assurance supervised by a central laboratory.

Flexible large-area ultrasound arrays for medical applications made using embossed polymer structures.

With the huge progress in micro-electronics and artificial intelligence, the ultrasound probe has become the bottleneck in further adoption of ultrasound beyond the clinical setting (e.g. home and monitoring applications). Today, ultrasound transducers have a small aperture, are bulky, contain lead and are expensive to fabricate. Furthermore, they are rigid, which limits their integration into flexible skin patches. New ways to fabricate flexible ultrasound patches have therefore attracted much attention recently. First prototypes typically use the same lead-containing piezo-electric materials, and are made using micro-assembly of rigid active components on plastic or rubber-like substrates. We present an ultrasound transducer-on-foil technology based on thermal embossing of a piezoelectric polymer. High-quality two-dimensional ultrasound images of a tissue mimicking phantom are obtained. Mechanical flexibility and effective area scalability of the transducer are demonstrated by functional integration into an endoscope probe with a small radius of 3 mm and a large area (91.2×14 mm2) non-invasive blood pressure sensor.

Safety and effectiveness of the short (0-1h) high sensitive troponin protocol in real-life practice.

AIM: Recent guidelines recommend the use of a short 0-1h high sensitive cardiac troponin (hs-cTn) algorithm in patients presenting with chest pain at the emergency department (ED). This retrospective observational study evaluates the safety and effectiveness of the new 0-1h hs-cTn I protocol in comparison with the standard 0-3h cTn I protocol for the diagnosis of acute myocardial infarction (AMI). METHODS: A total of two times 100 consecutive chest pain patients presenting at the ED in November/December 2018 (standard 0-3h cTn I group) and in November/December 2020 (short 0-1h hs-cTn I group) were enrolled. Decision making was based upon validated assay-specific cut-off values. RESULTS: The new 0-1h hs-cTn I protocol had a sensitivity of 100% (95% CI 83.2-100) and a negative predictive value of 100% to rule out AMI. The accuracy of rule-in was slightly lower with a specificity of 92.5% (95% CI 84.4-97.2). The overall protocol accuracy was 94% (95% CI 87.4-97.8) in the short 0-1h hs-cTn I group compared to 88% (95% CI 80.0-93.6) in the standard 0-3h cTn I group (p-value 0.14). The 0-1h hs-cTn I protocol was associated with a numerically higher rate of early hospital discharge compared to the conventional 0-3h cTn I protocol (47% versus 59%; p-value 0.09) and with a shorter median length of stay for those patients (mean 316 min versus 289 min; p-value 0.09). CONCLUSION: The abbreviated protocol based on the 0-1h hs-cTn I assays is effective and safe for the exclusion of AMI at the ED.

Validation of a rapid SARS-CoV-2 antibody test in general practice.

OBJECTIVES: To validate a rapid serological test (RST) for SARS-CoV-2 antibodies used in seroprevalence studies in healthcare providers, including primary healthcare providers (PHCPs) in Belgium. DESIGN: A phase III validation study of the RST (OrientGene) within a prospective cohort study. SETTING: Primary care in Belgium. PARTICIPANTS: Any general practitioner (GP) working in primary care in Belgium and any other PHCP from the same GP practice who physically manages patients were eligible in the seroprevalence study. For the validation study, all participants who tested positive (376) on the RST at the first testing timepoint (T1) and a random sample of those who tested negative (790) and unclear (24) were included. INTERVENTION: At T2, 4 weeks later, PHCPs performed the RST with fingerprick blood (index test) immediately after providing a serum sample to be analysed for the presence of SARS-CoV-2 immunoglobulin G antibodies using a two-out-of-three assay (reference test). PRIMARY AND SECONDARY OUTCOME MEASURES: The RST accuracy was estimated using inverse probability weighting to correct for missing reference test data, and considering unclear RST results as negative for the sensitivity and positive for the specificity. Using these conservative estimates, the true seroprevalence was estimated both for T2 and RST-based prevalence values found in a cohort study with PHCPs in Belgium. RESULTS: 1073 paired tests (403 positive on the reference test) were included. A sensitivity of 73% (a specificity of 92%) was found considering unclear RST results as negative (positive). For an RST-based prevalence at T1 (13.9), T2 (24.9) and T7 (70.21), the true prevalence was estimated to be 9.1%, 25.9% and 95.7%, respectively. CONCLUSION: The RST sensitivity (73%) and specificity (92%) make an RST-based seroprevalence below (above) 23% overestimate (underestimate) the true seroprevalence. TRIAL REGISTRATION NUMBER: NCT04779424.

Contrasting genomic consequences of anthropogenic reintroduction and natural recolonization in high-arctic wild reindeer.

Anthropogenic reintroduction can supplement natural recolonization in reestablishing a species' distribution and abundance. However, both reintroductions and recolonizations can give rise to founder effects that reduce genetic diversity and increase inbreeding, potentially causing the accumulation of genetic load and reduced fitness. Most current populations of the endemic high-arctic Svalbard reindeer (Rangifer tarandus platyrhynchus) originate from recent reintroductions or recolonizations following regional extirpations due to past overharvesting. We investigated and compared the genomic consequences of these two paths to reestablishment using whole-genome shotgun sequencing of 100 Svalbard reindeer across their range. We found little admixture between reintroduced and natural populations. Two reintroduced populations, each founded by 12 individuals around four decades (i.e. 8 reindeer generations) ago, formed two distinct genetic clusters. Compared to the source population, these populations showed only small decreases in genome-wide heterozygosity and increases in inbreeding and lengths of runs of homozygosity. In contrast, the two naturally recolonized populations without admixture possessed much lower heterozygosity, higher inbreeding and longer runs of homozygosity, possibly caused by serial population founder effects and/or fewer or more genetically related founders than in the reintroduction events. Naturally recolonized populations can thus be more vulnerable to the accumulation of genetic load than reintroduced populations. This suggests that in some organisms even small-scale reintroduction programs based on genetically diverse source populations can be more effective than natural recolonization in establishing genetically diverse populations. These findings warrant particular attention in the conservation and management of populations and species threatened by habitat fragmentation and loss.

Humoral and Cellular Immune Responses against SARS-CoV-2 after Third Dose BNT162b2 following Double-Dose Vaccination with BNT162b2 versus ChAdOx1 in Patients with Cancer.

PURPOSE: Patients with cancer display reduced humoral responses after double-dose COVID-19 vaccination, whereas their cellular response is more comparable with that in healthy individuals. Recent studies demonstrated that a third vaccination dose boosts these immune responses, both in healthy people and patients with cancer. Because of the availability of many different COVID-19 vaccines, many people have been boosted with a different vaccine from the one used for double-dose vaccination. Data on such alternative vaccination schedules are scarce. This prospective study compares a third dose of BNT162b2 after double-dose BNT162b2 (homologous) versus ChAdOx1 (heterologous) vaccination in patients with cancer. EXPERIMENTAL DESIGN: A total of 442 subjects (315 patients and 127 healthy) received a third dose of BNT162b2 (230 homologous vs. 212 heterologous). Vaccine-induced adverse events (AE) were captured up to 7 days after vaccination. Humoral immunity was assessed by SARS-CoV-2 anti-S1 IgG antibody levels and SARS-CoV-2 50% neutralization titers (NT50) against Wuhan and BA.1 Omicron strains. Cellular immunity was examined by analyzing CD4+ and CD8+ T-cell responses against SARS-CoV-2-specific S1 and S2 peptides. RESULTS: Local AEs were more common after heterologous boosting. SARS-CoV-2 anti-S1 IgG antibody levels did not differ significantly between homologous and heterologous boosted subjects [GMT 1,755.90 BAU/mL (95% CI, 1,276.95-2,414.48) vs. 1,495.82 BAU/mL (95% CI, 1,131.48-1,977.46)]. However, homologous-boosted subjects show significantly higher NT50 values against BA.1 Omicron. Subjects receiving heterologous boosting demonstrated increased spike-specific CD8+ T cells, including higher IFNγ and TNFα levels. CONCLUSIONS: In patients with cancer who received double-dose ChAdOx1, a third heterologous dose of BNT162b2 was able to close the gap in antibody response.