"How I would like AI used for my imaging": children and young persons' perspectives.

OBJECTIVES: Artificial intelligence (AI) tools are becoming more available in modern healthcare, particularly in radiology, although less attention has been paid to applications for children and young people. In the development of these, it is critical their views are heard. MATERIALS AND METHODS: A national, online survey was publicised to UK schools, universities and charity partners encouraging any child or young adult to participate. The survey was "live" for one year (June 2022 to 2023). Questions about views of AI in general, and in specific circumstances (e.g. bone fractures) were asked. RESULTS: One hundred and seventy-one eligible responses were received, with a mean age of 19 years (6-23 years) with representation across all 4 UK nations. Most respondents agreed or strongly agreed they wanted to know the accuracy of an AI tool that was being used (122/171, 71.3%), that accuracy was more important than speed (113/171, 66.1%), and that AI should be used with human oversight (110/171, 64.3%). Many respondents (73/171, 42.7%) felt AI would be more accurate at finding problems on bone X-rays than humans, with almost all respondents who had sustained a missed fracture strongly agreeing with that sentiment (12/14, 85.7%). CONCLUSIONS: Children and young people in our survey had positive views regarding AI, and felt it should be integrated into modern healthcare, but expressed a preference for a "medical professional in the loop" and accuracy of findings over speed. Key themes regarding information on AI performance and governance were raised and should be considered prior to future AI implementation for paediatric healthcare. CLINICAL RELEVANCE STATEMENT: Artificial intelligence (AI) integration into clinical practice must consider all stakeholders, especially paediatric patients who have largely been ignored. Children and young people favour AI involvement with human oversight, seek assurances for safety, accuracy, and clear accountability in case of failures. KEY POINTS: Paediatric patient's needs and voices are often overlooked in AI tool design and deployment. Children and young people approved of AI, if paired with human oversight and reliability. Children and young people are stakeholders for developing and deploying AI tools in paediatrics.

Post-mortem skeletal survey (PMSS) versus post-mortem computed tomography (PMCT) for the detection of corner metaphyseal lesions (CML) in children.

OBJECTIVES: Corner metaphyseal lesions (CMLs) are specific for child abuse but challenging to detect on radiographs. The accuracy of CT for CML detection is unknown. Our aim was to compare diagnostic accuracy for CML detection on post-mortem skeletal surveys (PMSS, plain radiography) versus post-mortem CT (PMCT). METHODS: A 10-year retrospective review was performed at a children's hospital for patients having PMSS, PMCT and histopathological correlation (reference standard) for suspected CMLs. Twenty-four radiologists independently reported the presence or absence of CMLs in all cases in a blinded randomised cross-over design across two rounds. Logistic regression models were used to compare accuracy between modalities. RESULTS: Twenty CMLs were reviewed for each of the 10 subjects (200 metaphyses in all). Among them, 20 CMLs were confirmed by bone histopathology. Sensitivity for these CMLs was significantly higher for PMSS (69.6%, 95% CI 61.7 to 76.7) than PMCT (60.5%, 95% CI 51.9 to 68.6). Using PMSS for detection of CMLs would yield one extra correct diagnosis for every 11.1 (95% CI 6.6 to 37.0) fractured bones. In contrast, specificity was higher on PMCT (92.7%, 95% CI 90.3 to 94.5) than PMSS (90.5%, 95% CI 87.6 to 92.8) with an absolute difference of 2.2% (95% CI 1.0 to 3.4, p < 0.001). More fractures were reported collectively by readers on PMSS (785) than on PMCT (640). CONCLUSION: PMSS remains preferable to PMCT for CML evaluation. Any investigation of suspected abuse or unexplained deaths should include radiographs of the limbs to exclude CMLs. CLINICAL RELEVANCE STATEMENT: In order to avoid missing evidence that could indicate child abuse as a contributory cause for death in children, radiographs of the limbs should be performed to exclude CMLs, even if a PMCT is being acquired. KEY POINTS: • Corner metaphyseal lesions (CMLs) are indicative for abuse, but challenging to detect. Skeletal surveys (i.e. radiographs) are standard practice; however, accuracy of CT is unknown. • Sensitivity for CML detection on radiographs is significantly higher than CT. • Investigation of unexplained paediatric deaths should include radiographs to exclude CMLs even if CT is also being performed.

Pre- and post-COVID-19 gender trends in authorship for paediatric radiology articles worldwide: a systematic review.

BACKGROUND: Gender inequalities in academic medicine persist despite progress over the past decade. Evidence-based targeted interventions are needed to reduce gender inequalities. OBJECTIVE: This systematic review aimed to investigate the impact of COVID-19 on gender trends in authorship of paediatric radiology research worldwide. MATERIALS AND METHODS: This prospectively registered, PRISMA-compliant systematic review searched the following databases: PubMed, MEDLINE, Web of Science, and Scopus from January 1, 2018, to May 29, 2023, with no restrictions on country of origin. Screening and data extraction occurred independently and in duplicate. Gender of first, last, and corresponding authors were determined using an artificial intelligence-powered, validated, multinational database ( www.genderize.io ). Two time periods were categorised according to the Johns Hopkins Center for Systems Science and Engineering: pre-COVID (prior to March 2020) and peak and post-COVID (March 2020 onwards). One-sample binomial testing was used to analyse proportion of authorship based on gender. Categorical variables were described as frequencies and percentages, and compared using testing chi-square or Fisher exact testing, with a threshold of P<0.05 representing statistical significance. RESULTS: In total, 922 articles were included with 39 countries represented. A statistically significant difference in authorship based on gender persisted during the peak and post-COVID time period (March 2020 onwards) where women represented a statistically significant lower proportion of last (35.5%) and corresponding (42.7%) authors (P<0.001, P=0.001, respectively). Statistically significant differences for first authors were not found in either period (P=0.08 and P=0.48). CONCLUSION: This study identifies differences in gender trends for authorship in paediatric radiology research worldwide. Future efforts to increase authorship by women are needed.

Artificial Intelligence in Paediatric Tuberculosis.

Tuberculosis (TB) continues to be a leading cause of death in children despite global efforts focused on early diagnosis and interventions to limit the spread of the disease. This challenge has been made more complex in the context of the coronavirus pandemic, which has disrupted the "End TB Strategy" and framework set out by the World Health Organization (WHO). Since the inception of artificial intelligence (AI) more than 60 years ago, the interest in AI has risen and more recently we have seen the emergence of multiple real-world applications, many of which relate to medical imaging. Nonetheless, real-world AI applications and clinical studies are limited in the niche area of paediatric imaging. This review article will focus on how AI, or more specifically deep learning, can be applied to TB diagnosis and management in children. We describe how deep learning can be utilised in chest imaging to provide computer-assisted diagnosis to augment workflow and screening efforts. We also review examples of recent AI applications for TB screening in resource constrained environments and we explore some of the challenges and the future directions of AI in paediatric TB.

Can artificial intelligence pass the Fellowship of the Royal College of Radiologists examination? Multi-reader diagnostic accuracy study.

OBJECTIVE: To determine whether an artificial intelligence candidate could pass the rapid (radiographic) reporting component of the Fellowship of the Royal College of Radiologists (FRCR) examination. DESIGN: Prospective multi-reader diagnostic accuracy study. SETTING: United Kingdom. PARTICIPANTS: One artificial intelligence candidate (Smarturgences, Milvue) and 26 radiologists who had passed the FRCR examination in the preceding 12 months. MAIN OUTCOME MEASURES: Accuracy and pass rate of the artificial intelligence compared with radiologists across 10 mock FRCR rapid reporting examinations (each examination containing 30 radiographs, requiring 90% accuracy rate to pass). RESULTS: When non-interpretable images were excluded from the analysis, the artificial intelligence candidate achieved an average overall accuracy of 79.5% (95% confidence interval 74.1% to 84.3%) and passed two of 10 mock FRCR examinations. The average radiologist achieved an average accuracy of 84.8% (76.1-91.9%) and passed four of 10 mock examinations. The sensitivity for the artificial intelligence was 83.6% (95% confidence interval 76.2% to 89.4%) and the specificity was 75.2% (66.7% to 82.5%), compared with summary estimates across all radiologists of 84.1% (81.0% to 87.0%) and 87.3% (85.0% to 89.3%). Across 148/300 radiographs that were correctly interpreted by >90% of radiologists, the artificial intelligence candidate was incorrect in 14/148 (9%). In 20/300 radiographs that most (>50%) radiologists interpreted incorrectly, the artificial intelligence candidate was correct in 10/20 (50%). Most imaging pitfalls related to interpretation of musculoskeletal rather than chest radiographs. CONCLUSIONS: When special dispensation for the artificial intelligence candidate was provided (that is, exclusion of non-interpretable images), the artificial intelligence candidate was able to pass two of 10 mock examinations. Potential exists for the artificial intelligence candidate to improve its radiographic interpretation skills by focusing on musculoskeletal cases and learning to interpret radiographs of the axial skeleton and abdomen that are currently considered "non-interpretable."

The T-cell clonal response to SARS-CoV-2 vaccination in inflammatory bowel disease patients is augmented by anti-TNF therapy and often deficient in antibody-responders

BackgroundVaccination against SARS-CoV-2 is a highly effective strategy to protect against infection, which is predominantly mediated by vaccine-induced antibodies. Postvaccination antibodies are robustly produced by those with inflammatory bowel disease (IBD) even on immune-modifying therapies but are blunted by anti-TNF therapy. In contrast, T-cell response which primarily determines long-term efficacy against disease progression,, is less well understood. We aimed to assess the post-vaccination T-cell response and its relationship to antibody responses in patients with inflammatory bowel disease (IBD) on immune-modifying therapies. MethodsWe evaluated IBD patients who completed SARS-CoV-2 vaccination using samples collected at four time points (dose 1, dose 2, 2 weeks after dose 2, 8 weeks after dose 2). T-cell clonal analysis was performed by T-cell Receptor (TCR) immunosequencing. The breadth (number of unique sequences to a given protein) and depth (relative abundance of all the unique sequences to a given protein) of the T-cell clonal response were quantified using reference datasets and were compared to antibody responses. ResultsOverall, 303 subjects were included (55% female; 5% with prior COVID) (Table). 53% received BNT262b (Pfizer), 42% mRNA-1273 (Moderna) and 5% Ad26CoV2 (J&J). The Spike-specific clonal response peaked 2 weeks after completion of the vaccine regimen (3- and 5-fold for breadth and depth, respectively); no changes were seen for non-Spike clones, suggesting vaccine specificity. Reduced T-cell clonal depth was associated with chronologic age, male sex, and immunomodulator treatment. It was preserved by non-anti-TNF biologic therapies, and augmented clonal depth was associated with anti-TNF treatment. TCR depth and breadth were associated with vaccine type; after adjusting for age and gender, Ad26CoV2 (J&J) exhibited weaker metrics than mRNA-1273 (Moderna) (p=0.01 for each) or BNT262b (Pfizer) (p=0.056 for depth). Antibody and T-cell responses were only modestly correlated. While those with robust humoral responses also had robust TCR clonal expansion, a substantial fraction of patients with high antibody levels had only a minimal T-cell clonal response. ConclusionAge, sex and select immunotherapies are associated with the T-cell clonal response to SARS-CoV-2 vaccines, and T-cell responses are low in many patients despite high antibody levels. These factors, as well as differences seen by vaccine type may help guide reimmunization vaccine strategy in immune-impaired populations. Further study of the effects of anti-TNF therapy on vaccine responses are warranted.

Post-Vaccination Symptoms after A Third Dose of mRNA SARS-CoV-2 Vaccination in Patients with Inflammatory Bowel Disease

Symptoms after SARS-CoV-2 primary vaccination among patients with inflammatory bowel disease (IBD) are generally of similar frequency, severity, and duration to those reported in the general population. The symptom profile after a 3rd mRNA vaccine dose in the predominantly immune-compromised IBD population is unknown. We aimed to assess symptomology after a 3rd or booster dose of mRNA vaccination in adults with IBD. We surveyed participants of the Coronavirus Risk Associations and Longitudinal Evaluation in IBD (CORALE-IBD) post-vaccination registry for symptom frequency and severity after a 3rd mRNA vaccine dose in an observational cohort study. In total, 524 participants (70% female, mean age 45 years) reported a third dose of mRNA vaccination through October 11, 2021. Overall, 41% reported symptoms after a third dose, with symptoms generally more frequent and more severe among participants younger than 55 years. The most frequent postvaccination symptoms were injection site pain (39%), fatigue or malaise (34%), and headache (23%). These symptoms were all less frequently reported after dose 3 than after dose 2. Gastrointestinal symptoms were reported by 8.8%, which was slightly more frequent than after dose 2 (7.8%). Those with severe symptoms after dose 2 were more likely to have severe symptoms after dose 3. These findings can reassure the IBD patient and provider communities that the likelihood and distribution of symptoms after a third mRNA vaccine dose are generally similar to those after a second dose, and that the frequency of postvaccination symptoms after dose 3 are generally lower than after dose 2.

Predominance of Distinct Autoantibodies in Response to SARS-CoV-2 Infection

BackgroundImproved knowledge regarding the prevalence and clinical significance of the broad spectrum of autoantibodies triggered by SARS-CoV2 infection can clarify the underlying pathobiology, enhance approaches to evaluating heterogeneity of COVID-19 clinical manifestations, and potentially guide options for targeting immunosuppressive therapy as the need for more effective interventions continues to evolve. In this study, we sought to determine the prevalence of autoimmune antibodies in diverse cohort of SARS-CoV-2 positive healthcare workers and measure the extent to which factors associated with triggered autoimmunity are activated even following mild and asymptomatic infection. MethodsAntigen microarrays were used to profile reactivity of IgG autoantibodies against 91 proteins and cytokines based on autoantibody profiling studies in autoimmune diseases. ResultsIn this discovery screening study, we found that 90% of the IgG positive individuals demonstrated reactivity to at least one autoantibody. When compared to results of the same assays conducted on samples from pre-COVID-19 controls, our primary cohort of individuals with SARS-CoV-2 IgG antibody positivity had significantly elevated IgG against twelve additional proteins including CHD3, CTLA4, HARS, IFNA4, INS, MIF, MX1, RNF41, S100A9, SRP19, TROVE2, and VEGFA. These findings confirmed that all severity levels of SARS-CoV-2 infection, even asymptomatic infections, trigger a robust and diverse autoimmune response; our results also highlight the utility of multiparametric autoantibody detection in this setting. InterpretationTaken together, our findings underscore the serological diversity underlying the clinical heterogeneity of COVID-19 infection and its sequelae, including the long-Covid phenotypes. FundingThis work was supported in part by Cedars-Sinai Medical Center (JEE; SC), the Erika J Glazer Family Foundation (JEE; JEVE; SC), CSMC Precision Health Grant (JFB), the F. Widjaja Family Foundation (JGB, GYM, DM), the Helmsley Charitable Trust (JGB, GYM, DM), and NIH grants K23-HL153888 (JEE) and DK062413 (DPBM). RESEARCH IN CONTEXTO_ST_ABSEvidence before this studyC_ST_ABSCurrently, several studies have shown the possible involvement of autoimmunity in patients affected by coronavirus disease 2019 (COVID-19). In contrast to cytokine storms, which tend to cause systemic, short-duration problems, autoantibodies (AABs) are thought to result in targeted, longer-term damage and development of autoimmune diseases. Added value of this studyAccording to our knowledge, we evaluated the largest number of protein antigens to characterize the prevalence and heterogeneity of the AABs signature in SARS-CoV-2 convalescent individuals. We examined autoimmune reactivity to SARS-CoV-2 in the absence of extreme clinical disease to acknowledge the existence of AABs even among those who had mild-to-moderate or no symptoms during their illness, as a hallmark of ongoing long-COVID syndrome. Through our analysis we suggest that VEGFA, MIF, IFNA4, SPP1 and APOH could be used as hallmark for SARS-CoV-2 infection and activation of the autoimmune system. Implications of all the available evidenceOur study comprehensively characterized the heterogeneity of the AABs signature in SARS-CoV-2 convalescent individuals. The results established a list of diagnostic signatures and potential therapeutic targets for long-Covid-19 patients although follow-up long-term studies are required. We believe that our findings will serve as a valuable resource, to drive further exploration of long-COVID syndrome pathogenesis.

Micro-CT yields high image quality in human fetal post-mortem imaging despite maceration.

BACKGROUND: Current clinical post-mortem imaging techniques do not provide sufficiently high-resolution imaging for smaller fetuses after pregnancy loss. Post-mortem micro-CT is a non-invasive technique that can deliver high diagnostic accuracy for these smaller fetuses. The purpose of the study is to identify the main predictors of image quality for human fetal post-mortem micro-CT imaging. METHODS: Human fetuses were imaged using micro-CT following potassium tri-iodide tissue preparation, and axial head and chest views were assessed for image quality on a Likert scale by two blinded radiologists. Simple and multivariable linear regression models were performed with demographic details, iodination, tissue maceration score and imaging parameters as predictor variables. RESULTS: 258 fetuses were assessed, with median weight 41.7 g (2.6-350 g) and mean gestational age 16 weeks (11-24 weeks). A high image quality score (> 6.5) was achieved in 95% of micro-CT studies, higher for the head (median = 9) than chest (median = 8.5) imaging. The strongest negative predictors of image quality were increasing maceration and body weight (p < 0.001), with number of projections being the best positive imaging predictor. CONCLUSIONS: High micro-CT image quality score is achievable following early pregnancy loss despite fetal maceration, particularly in smaller fetuses where conventional autopsy may be particularly challenging. These findings will help establish clinical micro-CT imaging services, addressing the need for less invasive fetal autopsy methods.

Review of study reporting guidelines for clinical studies using artificial intelligence in healthcare.

High-quality research is essential in guiding evidence-based care, and should be reported in a way that is reproducible, transparent and where appropriate, provide sufficient detail for inclusion in future meta-analyses. Reporting guidelines for various study designs have been widely used for clinical (and preclinical) studies, consisting of checklists with a minimum set of points for inclusion. With the recent rise in volume of research using artificial intelligence (AI), additional factors need to be evaluated, which do not neatly conform to traditional reporting guidelines (eg, details relating to technical algorithm development). In this review, reporting guidelines are highlighted to promote awareness of essential content required for studies evaluating AI interventions in healthcare. These include published and in progress extensions to well-known reporting guidelines such as Standard Protocol Items: Recommendations for Interventional Trials-AI (study protocols), Consolidated Standards of Reporting Trials-AI (randomised controlled trials), Standards for Reporting of Diagnostic Accuracy Studies-AI (diagnostic accuracy studies) and Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis-AI (prediction model studies). Additionally there are a number of guidelines that consider AI for health interventions more generally (eg, Checklist for Artificial Intelligence in Medical Imaging (CLAIM), minimum information (MI)-CLAIM, MI for Medical AI Reporting) or address a specific element such as the 'learning curve' (Developmental and Exploratory Clinical Investigation of Decision-AI) . Economic evaluation of AI health interventions is not currently addressed, and may benefit from extension to an existing guideline. In the face of a rapid influx of studies of AI health interventions, reporting guidelines help ensure that investigators and those appraising studies consider both the well-recognised elements of good study design and reporting, while also adequately addressing new challenges posed by AI-specific elements.

Paradoxical Sex-Specific Patterns of Autoantibodies Response to SARS-CoV-2 Infection

BackgroundAmidst the millions of individuals affected directly by the pandemic, pronounced sex differences in the susceptibility and response to SARS-CoV-2 infection remain poorly understood. Emerging evidence has highlighted the potential importance of autoimmune activation in modulating not only the acute response but also recovery trajectories following SARS-CoV-2 exposure. Given that immune-inflammatory activity can be sex-biased in the setting of severe COVID-19 illness, we deliberately examined sex-specific autoimmune reactivity to SARS-CoV-2 in the absence of extreme clinical disease. MethodsWe used a bead-based array containing over 90 autoantigens previously linked to a range of classic autoimmune diseases to assess autoantibody (AAB) titers in 177 participants. All participants had confirmed evidence of prior SARS-CoV-2 infection based on presence of positive anti-nucleocapsid IgG serology results (Abbott Diagnostics, Abbott Park, Illinois). We used multivariate analysis to determine whether sex-bias was associated with increased rates of AABs reactivity and symptom burden after SARS-CoV2 infection. Results82.4% of AABs reactivity was associated with being male compared to 17.6% with female. We found a diversity of AABs responses that exhibited sex-specific patterns of frequency distribution as well as associations with symptomatology and symptom burden. ConclusionOur results reveal a remarkable sex-specific prevalence and selectivity of AAB responses to SARS-CoV-2. Further understanding of the nature of triggered and persistent AAB activation among men and women exposed to SARS-CoV-2 will be essential for developing effective interventions against immune-mediated sequelae of COVID-19.

Imaging findings of multisystem inflammatory syndrome in children associated with COVID-19.

BACKGROUND: A hyperinflammatory immune-mediated shock syndrome has been recognised in children exposed to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes coronavirus disease 2019 (COVID-19). OBJECTIVE: To describe typical imaging findings in children with multisystem inflammatory syndrome associated with COVID-19. MATERIALS AND METHODS: During the first wave of the COVID-19 pandemic, imaging studies and clinical data from children treated for multisystem inflammatory syndrome were collected from multiple centres. Standardised case templates including demographic, biochemical and imaging information were completed by participating centres and reviewed by paediatric radiologists and paediatricians. RESULTS: We included 37 children (21 boys; median age 8.0 years). Polymerase chain reaction (PCR) testing was positive for SARS-CoV-2 in 15/37 (41%) children and immunoglobulins in 13/19 children (68%). Common clinical presentations were fever (100%), abdominal pain (68%), rash (54%), conjunctivitis (38%) and cough (32%). Thirty-three children (89%) showed laboratory or imaging findings of cardiac involvement. Thirty of the 37 children (81%) required admission to the intensive care unit, with good recovery in all cases. Chest radiographs demonstrated cardiomegaly in 54% and signs of pulmonary venous hypertension/congestion in 73%. The most common chest CT abnormalities were ground-glass and interstitial opacities (83%), airspace consolidation (58%), pleural effusion (58%) and bronchial wall thickening (42%). Echocardiography revealed impaired cardiac function in half of cases (51%) and coronary artery abnormalities in 14%. Cardiac MRI showed myocardial oedema in 58%, pericardial effusion in 42% and decreased left ventricular function in 25%. Twenty children required imaging for abdominal symptoms, the commonest abnormalities being free fluid (71%) and terminal ileum wall thickening (57%). Twelve children underwent brain imaging, showing abnormalities in two cases. CONCLUSION: Children with multisystem inflammatory syndrome showed pulmonary, cardiac, abdominal and brain imaging findings, reflecting the multisystem inflammatory disease. Awareness of the imaging features of this disease is important for early diagnosis and treatment.

Adverse Events Following SARS-CoV-2 mRNA Vaccination Among Patients with Inflammatory Bowel Disease

Patients with immune-mediated inflammatory diseases (IMID) such as inflammatory bowel disease (IBD) on immunosuppressive and biologic therapies were largely excluded from SARS-CoV-2 mRNA vaccine trials. We thus evaluated post-mRNA vaccination adverse events (AE) in 246 vaccinated adults with IBD participating in a longitudinal vaccine registry. In general, AE frequency was similar to that reported in the general population. As in the general population, AE were more common among younger patients, and those with prior COVID-19. We additionally found that AE were less common in individuals receiving biologic therapy. Those with IBD and other IMID on these commonly prescribed therapies can be reassured that the AE risk is likely not increased, and may be reduced, while on biologics.

Prior COVID-19 Infection and Antibody Response to Single Versus Double Dose mRNA SARS-CoV-2 Vaccination

The double dose regimen for mRNA vaccines against SARS-CoV-2 presents both a hope and a challenge for global efforts to curb the COVID-19 pandemic. With supply chain logistics impacting the rollout of population-scale vaccination programs, increasing attention has turned to the potential efficacy of single versus double dose vaccine administration for select individuals. To this end, we examined response to Pfizer-BioNTech mRNA vaccine in a large cohort of healthcare workers including those with versus without prior COVID-19 infection. For all participants, we quantified circulating levels of SARS-CoV-2 anti-spike (S) protein IgG at baseline prior to vaccine, after vaccine dose 1, and after vaccine dose 2. We observed that the anti-S IgG antibody response following a single vaccine dose in persons who had recovered from confirmed prior COVID-19 infection was similar to the antibody response following two doses of vaccine in persons without prior infection (P[≥]0.58). Patterns were similar for the post-vaccine symptoms experienced by infection recovered persons following their first dose compared to the symptoms experienced by infection naive persons following their second dose (P=0.66). These results support the premise that a single dose of mRNA vaccine could provoke in COVID-19 recovered individuals a level of immunity that is comparable to that seen in infection naive persons following a double dose regimen. Additional studies are needed to validate our findings, which could allow for public health programs to expand the reach of population wide vaccination efforts.

Thoracic imaging of coronavirus disease 2019 (COVID-19) in children: a series of 91 cases.

BACKGROUND: Pulmonary infection with SARS-CoV-2 virus (severe acute respiratory syndrome coronavirus 2; COVID-19) has rapidly spread worldwide to become a global pandemic. OBJECTIVE: To collect paediatric COVID-19 cases worldwide and to summarize both clinical and imaging findings in children who tested positive on polymerase chain reaction testing for SARS-CoV-2. MATERIALS AND METHODS: Data were collected by completion of a standardised case report form submitted to the office of the European Society of Paediatric Radiology from March 12 to April 8, 2020. Chest imaging findings in children younger than 18 years old who tested positive on polymerase chain reaction testing for SARS-CoV-2 were included. Representative imaging studies were evaluated by multiple senior paediatric radiologists from this group with expertise in paediatric chest imaging. RESULTS: Ninety-one children were included (49 males; median age: 6.1 years, interquartile range: 1.0 to 13.0 years, range: 9 days-17 years). Most had mild symptoms, mostly fever and cough, and one-third had coexisting medical conditions. Eleven percent of children presented with severe symptoms and required intensive unit care. Chest radiographs were available in 89% of patients and 10% of them were normal. Abnormal chest radiographs showed mainly perihilar bronchial wall thickening (58%) and/or airspace consolidation (35%). Computed tomography (CT) scans were available in 26% of cases, with the most common abnormality being ground glass opacities (88%) and/or airspace consolidation (58%). Tree in bud opacities were seen in 6 of 24 CTs (25%). Lung ultrasound and chest magnetic resonance imaging were rarely utilized. CONCLUSION: It seems unnecessary to perform chest imaging in children to diagnose COVID-19. Chest radiography can be used in symptomatic children to assess airway infection or pneumonia. CT should be reserved for when there is clinical concern to assess for possible complications, especially in children with coexisting medical conditions.

Bacterial modification of the host glycosaminoglycan heparan sulfate modulates SARS-CoV-2 infectivity

The human microbiota has a close relationship with human disease and it remodels components of the glycocalyx including heparan sulfate (HS). Studies of the severe acute respiratory syndrome coronavirus (SARS-CoV-2) spike protein receptor binding domain suggest that infection requires binding to HS and angiotensin converting enzyme 2 (ACE2) in a codependent manner. Here, we show that commensal host bacterial communities can modify HS and thereby modulate SARS-CoV-2 spike protein binding and that these communities change with host age and sex. Common human-associated commensal bacteria whose genomes encode HS-modifying enzymes were identified. The prevalence of these bacteria and the expression of key microbial glycosidases in bronchoalveolar lavage fluid (BALF) was lower in adult COVID-19 patients than in healthy controls. The presence of HS-modifying bacteria decreased with age in two large survey datasets, FINRISK 2002 and American Gut, revealing one possible mechanism for the observed increase in COVID-19 susceptibility with age. In vitro, bacterial glycosidases from unpurified culture media supernatants fully blocked SARS-CoV-2 spike binding to human H1299 protein lung adenocarcinoma cells. HS-modifying bacteria in human microbial communities may regulate viral adhesion, and loss of these commensals could predispose individuals to infection. Understanding the impact of shifts in microbial community composition and bacterial lyases on SARS-CoV-2 infection may lead to new therapeutics and diagnosis of susceptibility. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/238444v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@14ff1ecorg.highwire.dtl.DTLVardef@193d84corg.highwire.dtl.DTLVardef@15d6f9eorg.highwire.dtl.DTLVardef@14b16c6_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract. Diagram of hypothesis for bacterial mediation of SARS-CoV-2 infection through heparan sulfate (HS).It is well known that host microbes groom the mucosa where they reside. Recent investigations have shown that HS, a major component of mucosal layers, is necessary for SARS-CoV-2 infection. In this study we examine the impact of microbial modification of HS on viral attachment. C_FIG

SARS-CoV-2 Seroprevalence Across a Diverse Cohort of Healthcare Workers

ImportanceAntibody testing is important for understanding patterns of exposure and potential immunity to SARS-CoV-2. Prior data on seroprevalence have been subject to variations in selection of individuals and nature as well as timing of testing in relation to exposures. ObjectiveWe sought to determine the extent of SARS-CoV-2 seroprevalance and the factors associated with seroprevelance across a diverse cohort of healthcare workers. DesignObservational cohort study of healthcare workers, including SARS-CoV-2 serology testing and participant questionaires. ParticipantsA diverse and unselected population of adults (n=6,062) employed in a multi-site healthcare delivery system located in Los Angeles County, including individuals with direct patient contact and others with non-patient-oriented work functions. ExposureExposure and infection with the SARS-CoV-2 virus, as determined by seropositivity. Main OutcomesUsing Bayesian and multi-variate analyses, we estimated seroprevalence and factors associated with seropositivity and antibody titers, including pre-existing demographic and clinical characteristics; potential Covid-19 illness related exposures; and, symptoms consistent with Covid-19 infection. ResultsWe observed a seroprevalence rate of 4.1%, with anosmia as the most prominently associated self-reported symptom in addition to fever, dry cough, anorexia, and myalgias. After adjusting for potential confounders, pre-existing medical conditions were not associated with antibody positivity. However, seroprevalence was associated with younger age, Hispanic ethnicity, and African-American race, as well as presence of either a personal or household member having a prior diagnosis of Covid-19. Importantly, African American race and Hispanic ethnicity were associated with antibody positivity even after adjusting for personal Covid-19 diagnosis status, suggesting the contribution of unmeasured structural or societally factors. Notably, number of people, or children, in the home was not associated with antibody positivity. Conclusion and RelevanceThe demographic factors associated with SARS-CoV-2 seroprevalence among our healthcare workers underscore the importance of exposure sources beyond the workplace. The size and diversity of our study population, combined with robust survey and modeling techniques, provide a vibrant picture of the demographic factors, exposures, and symptoms that can identify individuals with susceptibility as well as potential to mount an immune response to Covid-19. Key PointsO_ST_ABSQuestionC_ST_ABSWhat is the SARS-CoV-2 IgG seroprevalence rate across a large and diverse healthcare worker population, and which clinical, envionrmental, and symptom-based measures are associated with seropositivity? FindingsWe observed a seroprevalence rate of 4.1%. Adjusting for potential confounders, seropositivity was associated with younger age, Hispanic ethnicity, African-American race, and the symptom of anosmia, while not significantly associated with any pre-existing medical conditions. MeaningFactors associated with SARS-CoV-2 seroprevalence among our healthcare workers underscore the importance of exposure sources beyond the workplace.

SARS-CoV-2 Seroprevalence in Relation to Timing of Symptoms

Of individuals with SARS-CoV-2 IgG antibody testing performed, those who contemporaneously experienced a cluster of Covid-19 relevant symptoms in the 1-2 months preceding the antibody assay were more likely to test positive whereas those who experienced the symptom clustering in the prior 3-6 months were more likely to test negative. These findings suggest that antibodies likely wane over a period of months, particularly in relation to the timing of symptoms.

Pre-Existing Characteristics Associated with Covid-19 Illness Severity

BackgroundCertain individuals, when infected by SARS-CoV-2, tend to develop the more severe forms of Covid-19 illness for reasons that remain unclear. MethodsWe studied N=442 patients who presented with laboratory confirmed Covid-19 illness to our U.S. metropolitan healthcare system. We curated data from the electronic health record, and used multivariable logistic regression to examine the association of pre-existing traits with a Covid-19 illness severity defined by level of required care: need for hospital admission, need for intensive care, and need for intubation. ResultsOf all patients studied, 48% required hospitalization, 17% required intensive care, and 12% required intubation. In multivariable-adjusted analyses, patients requiring a higher levels of care were more likely to be older (OR 1.5 per 10 years, P<0.001), male (OR 2.0, P=0.001), African American (OR 2.1, P=0.011), obese (OR 2.0, P=0.021), with diabetes mellitus (OR 1.8, P=0.037), and with a higher comorbidity index (OR 1.8 per SD, P<0.001). Several clinical associations were more pronounced in younger compared to older patients (Pinteraction<0.05). Of all hospitalized patients, males required higher levels of care (OR 2.5, P=0.003) irrespective of age, race, or morbidity profile. ConclusionsIn our healthcare system, greater Covid-19 illness severity is seen in patients who are older, male, African American, obese, with diabetes, and with greater overall comorbidity burden. Certain comorbidities paradoxically augment risk to a greater extent in younger patients. In hospitalized patients, male sex is the main determinant of needing more intensive care. Further investigation is needed to understand the mechanisms underlying these findings.