Potential impact of annual vaccination with reformulated COVID-19 vaccines: lessons from the U.S. COVID-19 Scenario Modeling Hub (preprint)

ImportanceCOVID-19 continues to cause significant hospitalizations and deaths in the United States. Its continued burden and the impact of annually reformulated vaccines remain unclear. ObjectiveTo project COVID-19 hospitalizations and deaths from April 2023-April 2025 under two plausible assumptions about immune escape (20% per year and 50% per year) and three possible CDC recommendations for the use of annually reformulated vaccines (no vaccine recommendation, vaccination for those aged 65+, vaccination for all eligible groups). DesignThe COVID-19 Scenario Modeling Hub solicited projections of COVID-19 hospitalization and deaths between April 15, 2023-April 15, 2025 under six scenarios representing the intersection of considered levels of immune escape and vaccination. State and national projections from eight modeling teams were ensembled to produce projections for each scenario. SettingThe entire United States. ParticipantsNone. ExposureAnnually reformulated vaccines assumed to be 65% effective against strains circulating on June 15 of each year and to become available on September 1. Age and state specific coverage in recommended groups was assumed to match that seen for the first (fall 2021) COVID-19 booster. Main outcomes and measuresEnsemble estimates of weekly and cumulative COVID-19 hospitalizations and deaths. Expected relative and absolute reductions in hospitalizations and deaths due to vaccination over the projection period. ResultsFrom April 15, 2023-April 15, 2025, COVID-19 is projected to cause annual epidemics peaking November-January. In the most pessimistic scenario (high immune escape, no vaccination recommendation), we project 2.1 million (90% PI: 1,438,000-4,270,000) hospitalizations and 209,000 (90% PI: 139,000-461,000) deaths, exceeding pre-pandemic mortality of influenza and pneumonia. In high immune escape scenarios, vaccination of those aged 65+ results in 230,000 (95% CI: 104,000-355,000) fewer hospitalizations and 33,000 (95% CI: 12,000-54,000) fewer deaths, while vaccination of all eligible individuals results in 431,000 (95% CI: 264,000-598,000) fewer hospitalizations and 49,000 (95% CI: 29,000-69,000) fewer deaths. Conclusion and RelevanceCOVID-19 is projected to be a significant public health threat over the coming two years. Broad vaccination has the potential to substantially reduce the burden of this disease. Key pointsO_ST_ABSQuestionC_ST_ABSWhat is the likely impact of COVID-19 from April 2023-April 2025 and to what extent can vaccination reduce hospitalizations and deaths? FindingsUnder plausible assumptions about viral evolution and waning immunity, COVID-19 will likely cause annual epidemics peaking in November-January over the two-year projection period. Though significant, hospitalizations and deaths are unlikely to reach levels seen in previous winters. The projected health impacts of COVID-19 are reduced by 10-20% through moderate use of reformulated vaccines. MeaningCOVID-19 is projected to remain a significant public health threat. Annual vaccination can reduce morbidity, mortality, and strain on health systems.

PROGNOSTIC FACTORS AND EFFICACY OF DMARD USE IN GCA: RESULTS FROM THE PROSPECTIVE, LONGITUDINAL,MULTI-CENTRE HAS-GCA STUDY

BackgroundGCA is a critically ischemic large vessel vasculitis, varying in extent, severity and outcomes, hence requires disease stratification using clinical, laboratory and imaging parameters, for targeted management. Although DMARDs are used, the effectiveness in real life, such adjuvants remain un-elucidated. We performed a prospective, multi centre cohort study of new GCA stratified into remitting, relapsing, refractory, ischemic disease.ObjectivesWe assessed prognostic factors and compared critical outcomes such as remission with glucocorticoid (GC) monotherapy versus GC plus DMARDs in the first 12 months.MethodsHAS GCA study (1) recruited consecutive patients with new onset GCA from 7 centres (UK, Italy, Spain, Netherlands). diagnosis was confirmed used a modified GiACTA criteria at 6 months follow up. All underwent ultrasound (bilateral common, parietal, frontal temporal arteries, and axillary arteries) using accepted standard cut-off values [2]. GCA patients had US at baseline,1,3,6,12 months and halo count (HC) and Halo score (Temporal TAHS, axillary AAHS, total THS) assessed [3]. The primary outcome- remission at 12 months (absence of signs/symptoms, CRP<5 mg/dl, prednisolone < 5 mg daily). Results are reported as descriptive statistics.Results229 participants included in the study (GCA- 84 (36.68 %) (Figure 1). Study recruited during Covid pandemic,73 completed,11 lost to follow-up (died -7, withdrawn-4). The deceased/withdrawn patients (compared to completers) were older (80 v74 yrs, p=0.018), preponderantly male (73% v 36%, p=0.043) with visual symptoms (91% v 49%, p=0.010) partial/total sight loss (55% v 21%, p=0.024), lower CRP (21 v 68, p=0.061) and ESR (42 v 62, p= 0.317).Of 73 completers 36 required early DMARDs (<12 weeks) for refractory/relapsing/ischemic/GC related AEs. This group had more LV involvement (50% v 11%, p=0.0003), Remission attained at 12 months 32/36 (89%) in DMARD group was comparable to the remitting GC monotherapy group 33/37 (89%) with comparable cumulative GC doses (Figure 1, Table 1).At 12-months follow up, median TAHS, AAHS and THS reduced from 13 to 3, 12 to 9 and 21.5 to 12, respectively.ConclusionOur study suggests, elderly males with visual symptoms, sight loss, lower CRP are a high-risk group with increased mortality within GCA. Difficult to treat disease is seen in half of all patients especially with LV involvement. This group responds well to early DMARD use achieving remission comparable to the remitting group at 12 months. Current therapies fail to achieve remission in 9.5 % of cases. HS and HC show significant improvement mirroring clinical outcomes during first 12 months of therapy.References[1]Sebastian A et al. BMC Rheum. 2020[2]Schafer VS et al. Rheumatology 2017[3]van der Geest KSM et al. ARD 2020Table 1.comparison between the DMARD-used group and only GC group in all the GCA completed the 12 months follow upPatients' characteristicsGCA with completed follow-up (n=73)GCA treated with DMARD=36GCA not treated with DMARD=37Age, median (range) years73.5 (60-89)76 (60-89)Sex, Females, n (%)23 (64)24 (65)US halo score (HS)/IMT median (range)Temporal artery HS11 (0-23)13 (1-22)Axillary artery HS12 (0-21)12 (0-18)Axillary artery IMT (mm)0.77 (0.33-2.6)0.82 (0.39-1.21)Total HS22.5 (2-41)21 (5-40)Clinical features, n (%)Temporal headache25(69)30 (81)Scalp tenderness17 (47)19 (51)Jaw & Tongue claudication22 (61)24 (65)Polymyalgic symptoms21 (58)13 (35)Constitutional symptoms21 (58)18 (49)Any visual disturbance15 (42)21 (57)Partial or complete vision loss8 (22)7 (19)History of PMR6 (17)3 (8)Exam findings, n (%)Temporal artery abnormality24 (67)30 (81)AION/ CRAO8 (22)6 (16)Ocular nerve palsy1 (3)3 (8)Lab markers at baseline, median (range)CRP mg/dL,72.2 (6.4-292)59 (6-206)ESR mm/hr67 (9-130)57 (2-120)GC treatment, median (range)GC starting dose, (baseline)45 (0-60)50 (0-60)GC dose at 12m,5 (0-25)2.5 (0-10)Cumulative GC dose at 12m4627.5 (2600-10260.5)4622.5 (944-10737.5)Remission with prednisolone dose ≤5 mg at 12m, n (%)32 (89)33 (89)Acknowledgements:NIL.Disclosure of InterestsBhaskar Dasgupta Consultant of: Roche, Chugai, Sanofi, Grant/research support from: Roche, Sanofi, AbbVie, and GlaxoSmithKline, Kornelis van der Geest Speakers bureau: Roche, Grant/research support from: AbbVie, Alessandro Tomelleri: None declared, Pierluigi Macchioni: None declared, Giulia Klinowski: None declared, Carlo Salvarani: None declared, Abdul Kayani: None declared, Mohammad Tariq: None declared, Diana Prieto-Peña: None declared, Edoardo Conticini: None declared, Muhammad Khurshid: None declared, Sue Inness: None declared, Jo Jackson: None declared, Alwin Sebastian: None declared.

Mucosal plasma cells are required to protect the upper airway and brain from infection.

While blood antibodies mediate protective immunity in most organs, whether they protect nasal surfaces in the upper airway is unclear. Using multiple viral infection models in mice, we found that blood-borne antibodies could not defend the olfactory epithelium. Despite high serum antibody titers, pathogens infected nasal turbinates, and neurotropic microbes invaded the brain. Using passive antibody transfers and parabiosis, we identified a restrictive blood-endothelial barrier that excluded circulating antibodies from the olfactory mucosa. Plasma cell depletions demonstrated that plasma cells must reside within olfactory tissue to achieve sterilizing immunity. Antibody blockade and genetically deficient models revealed that this local immunity required CD4+ T cells and CXCR3. Many vaccine adjuvants failed to generate olfactory plasma cells, but mucosal immunizations established humoral protection of the olfactory surface. Our identification of a blood-olfactory barrier and the requirement for tissue-derived antibody has implications for vaccinology, respiratory and CNS pathogen transmission, and B cell fate decisions.

Lung Transplantation for COVID-19 Pulmonary Sequelae.

BACKGROUND: The role of lung transplantation for coronavirus disease 2019 (COVID-19)-related lung failure is evolving as the pandemic persists. METHODS: From January 2021 to April 2022, 20 patients (median age 62 y; range 31-77) underwent lung transplantation for COVID-related lung failure at our institution. We reviewed their clinical and intraoperative characteristics and early outcomes including postoperative complications. RESULTS: Eleven patients (55%) had chronic lung disease when they contracted COVID-19. All 20 patients required hospitalization for antivirus treatment. Median lung allocation score was 74.7 (33.1-94.0). Thirteen patients (65%) underwent single-lung transplants, and 7 patients (35%) underwent double-lung transplants. Concomitant coronary artery bypass graft surgery was performed in 2 (10%) patients because of severe coronary artery disease. Postoperatively, venovenous extracorporeal membrane oxygenation was needed in 3 patients (15%) because of severe primary graft dysfunction; all were eventually weaned. Ten patients (50%) experienced deep venous thrombosis, and 1 eventually developed a major pulmonary embolus. The median intensive care unit stay and hospital stays were 6.5 d (3-44) and 18 d (7-77), respectively. During a median follow-up of 201 d (47-418), we experienced 1 late mortality due to COVID-19-related myocarditis. Among the 13 patients with single-lung transplant, 5 demonstrated improvement in their native lungs. CONCLUSIONS: Lung transplantation yielded favorable early outcomes in a heterogeneous patient cohort that included older patients, obese patients, and patients with coronary artery disease or preexisting chronic lung disease. Our data also shed light on the transforming role of lung transplantation for the pulmonary sequelae of a complex multisystem COVID-19 disorder.

Scientific and subject impact of Revista del Cuerpo Medico Hospital Nacional Almanzor Aguinaga Asenjo: An bibliometric analysis since 2011 to 2020

Introduction: Peru has several journals about biomedical areas, but a few serial publications are visible and indexing in different global indexing media. Objective: To analyze the main publication characteristics from Revista del Cuerpo Medico Hospital Nacional Almanzor Aguinaga Asenjo (Chiclayo) based on bibliometric methods. Methods: Descriptive study that analyzes 587 articles published by the journal from 2011 to 2020, based on bibliometric methods and indicators: citations, scientific impact and co-word analysis. Results: Original articles were the highest types of document published (60%;(X) over bar =66). Published research articles on general medicine received more impact in previous years than the recents. Most frequent terms analyzed were studies about patients from hospitals in Chiclayo city (Lambayeque) with covid-19 clinical cases. Conclusion: Revista del Cuerpo Medico HNAAA is emerging as an important scholarly publication to do visible local, national, and international production due to health subject coverage into medical specialties.

Persistent post-COVID-19 smell loss is associated with immune cell infiltration and altered gene expression in olfactory epithelium.

SARS-CoV-2 causes profound changes in the sense of smell, including total smell loss. Although these alterations are often transient, many patients with COVID-19 exhibit olfactory dysfunction that lasts months to years. Although animal and human autopsy studies have suggested mechanisms driving acute anosmia, it remains unclear how SARS-CoV-2 causes persistent smell loss in a subset of patients. To address this question, we analyzed olfactory epithelial samples collected from 24 biopsies, including from nine patients with objectively quantified long-term smell loss after COVID-19. This biopsy-based approach revealed a diffuse infiltrate of T cells expressing interferon-γ and a shift in myeloid cell population composition, including enrichment of CD207+ dendritic cells and depletion of anti-inflammatory M2 macrophages. Despite the absence of detectable SARS-CoV-2 RNA or protein, gene expression in the barrier supporting cells of the olfactory epithelium, termed sustentacular cells, appeared to reflect a response to ongoing inflammatory signaling, which was accompanied by a reduction in the number of olfactory sensory neurons relative to olfactory epithelial sustentacular cells. These findings indicate that T cell-mediated inflammation persists in the olfactory epithelium long after SARS-CoV-2 has been eliminated from the tissue, suggesting a mechanism for long-term post-COVID-19 smell loss.

Ameliorating Atopy by Compensating Micronutritional Deficiencies in Immune Cells: A Double-Blind Placebo-Controlled Pilot Study.

BACKGROUND: Functional iron deficiency facilitates allergy development and amplifies the symptom burden in people experiencing allergies. Previously we selectively delivered micronutrients to immune cells with ß-lactoglobulin as carrier (holoBLG), resulting in immune resilience and allergy prevention. OBJECTIVE: The clinical efficacy of a food for special medical purposes-lozenge containing ß-lactoglobulin with iron, polyphenols, retinoic acid, and zinc (holoBLG lozenge) was assessed in allergic women. METHODS: In a randomized, double-blind, placebo-controlled pilot study, grass- and/or birch pollen-allergic women (n = 51) were given holoBLG or placebo lozenges over 6 months. Before and after dietary supplementation, participants were nasally challenged and the blood was analyzed for immune and iron parameters. Daily symptoms, medications, pollen concentrations, and well-being were recorded by an electronic health application. RESULTS: Total nasal symptom score after nasal provocations improved by 42% in the holoBLG group versus 13% in the placebo group. The combined symptom medication score during the birch peak and entire season as well as the entire grass pollen season improved in allergic subjects supplemented with the holoBLG lozenge by 45%, 31%, and 40%, respectively, compared with the placebo arm. Participants ingesting the holoBLG lozenge had improved iron status with increased hematocrit values, decreased red cell distribution width, and higher iron levels in circulating CD14+ cells compared with the placebo group. CONCLUSIONS: Targeted micronutrition with the holoBLG lozenge seemed to be effective in elevating the labile iron levels in immune cells and reducing the symptom burden in allergic women in this pilot study. The underlying allergen-independent mechanism provides evidence that dietary nutritional supplementation of the immune system is one of the ways to combat atopy.

Complete (Humoral and Cellular) Response to Vaccination against COVID-19 in a Group of Healthcare Workers-Assessment of Factors Affecting Immunogenicity

Vaccination is the best way to limit the extent of the COVID pandemic. Knowledge of the duration of the immune response will allow the planning of a vaccination protocol. This study aims to validate the complete (humoral and cellular) immune responses over time in large population groups following the full vaccination of healthcare professionals in real-life conditions and to assess the relationship between antibody levels and T-cell activity in relation to the characteristics of the study group. The samples for the study were obtained from volunteers (staff of two hospitals) on three occasions: before vaccination, T0, then 4-9 weeks after full vaccination (two doses BNT162b2), T1, and 7-9 months after vaccination, T2. The humoral response was investigated by the titre of anti-SARS-CoV-2 IgG antibodies to S1 protein. Assays were performed three times at intervals. The cellular response was assessed in a subgroup of 189 subjects by QuanT-Cell SARS-CoV-2 (IGRA). The assay was performed once. A group of 344 subjects fully vaccinated with the BNT162b2 vaccine were included in the study. The humoral response was observed in 100% of subjects at both 4-7 weeks and 7-9 months, but antibody titres fell by almost 90% in this interval. The cellular response was observed in 94% (177/189) of subjects 7-9 months after the second dose of vaccine. In subjects with a negative cellular response, eight out of 12 smoked. A factor associated with greater immunogenicity of vaccination was past SARS-CoV-2 infection. The administration of full BNT162b2 vaccination (two doses) induces humoral and cellular responses detectable even more than six months after vaccination. Smoking may be a factor associated with impaired cellular response to vaccination.

Persistent post-COVID-19 smell loss is associated with inflammatory infiltration and altered olfactory epithelial gene expression (preprint)

Most human subjects infected by SARS-CoV-2 report an acute alteration in their sense of smell, and more than 25% of COVID patients report lasting olfactory dysfunction. While animal studies and human autopsy tissues have suggested mechanisms underlying acute loss of smell, the pathophysiology that underlies persistent smell loss remains unclear. Here we combine objective measurements of smell loss in patients suffering from post-acute sequelae of SARS-CoV-2 infection (PASC) with single cell sequencing and histology of the olfactory epithelium (OE). This approach reveals that the OE of patients with persistent smell loss harbors a diffuse infiltrate of T cells expressing interferon-gamma; gene expression in sustentacular cells appears to reflect a response to inflammatory signaling, which is accompanied by a reduction in the number of olfactory sensory neurons relative to support cells. These data identify a persistent epithelial inflammatory process associated with PASC, and suggests mechanisms through which this T cell-mediated inflammation alters the sense of smell.

Direkte Katalytische C‐Glykosylierung von Arenen: beschleunigte Synthese des Remdesivir‐Nucleosids

Seit Beginn des Jahres 2020 wird nach einer effektiven Lösung im Kampf gegen SARS‐CoV‐2 gesucht, vor allem durch Entwicklung verlässlicher Impfstoffe, welche die Verbreitung des Virus verhindern, und durch die Untersuchung bereits für andere Indikationen zugelassener Wirkstoffe. Diesbezüglich ist die Anwendung der antiviralen Prodrug Remdesivir immer noch am weitesten verbreitet, allerdings beschränkt sich die Synthese auf Schutzgruppen, sauerstoffsensitive Reagenzien und kryogene Temperaturen, weshalb eine kosteneffiziente Herstellung nicht immer gewährleistet werden kann. Um zur Lösung dieses Problems beizutragen, konzentrierten wir uns auf die Entwicklung einer direkten Addition von (Hetero)arenen an ungeschützte Zucker. Hier berichten wir von einer silyliumkatalysierten und vollkommen stereoselektiven C‐Glykosylierung, die zunächst offenkettige Polyole liefert, welche schließlich durch Cyclisierung unter kinetischer oder thermodynamischer Kontrolle zur α‐ oder β‐Furanose umgesetzt werden. Die Methode ermöglicht raschen Zugang zu Remdesivir‐Intermediat GS‐441524 nach anschließender Mn‐katalysierter C−H‐Oxidation sowie Deoxycyanierung.

Safety of extracurricular activities in times of pandemic by SARS-CoV-2. Prospective study in pediatric population

Introduction: the coronavirus disease 2019 pandemic has compelled the implementation of various measures to mitigate the impact of an inevitable increase in COVID-19 cases, such as the closure of schools. Upon their reopening, given that physical activity in childhood and adolescence is crucial for optimal development, we considered whether extracurricular athletic activities are safe in the COVID age. Material and methods: we conducted a longitudinal, observational and descriptive study. We followed up 717 students and instructors from a municipal sports organization that participated in sports activities offered between September and December 2020. When a positive case was identified, the staff contacted the family, filling in the data collection form and monitoring the students. Results: there was only 1 detected case SARS-CoV-2 infection among the 679 students and 38 adult instructors included in the study. It occurred in an adolescent aged 13 years that played basketball and acquired the infection from a family member and developed mild symptoms;both the boy and the peers in his consistent contact group were quarantined for 10 days without identification of additional cases. Discussion: our results suggests that if athletic activities are carried out in controlled groups in optimi-sed environments and adhering to health standards, sports facilities can be safe spaces for the paedia-tric population with a low SARS-CoV-2 transmission rate. We did not identify any outbreaks in the sample, having implemented the appropriate preventive measures and verified strict adherence by the students. Nevertheless, it is important to keep accurate records of current students for contact tracing and to guide the implementation of preventive measures, both general and specific to particular sports activities, with the aim of minimising risk. © 2021, Spanish Association of Primary Care Pediatrics. All rights reserved.

A review of the clinical assistant workforce at a district general hospital during the COVID-19 pandemic.

INTRODUCTION: In April 2020, a new workforce of clinical assistants (CAs), comprising predominantly of medical students, began work at Northampton General Hospital. Clinical-years students had a role similar to final-year student assistants; pre-clinical students were offered a healthcare assistant role. This research aimed to evaluate both CAs' and clinicians' perceptions of this programme. METHODS: Separate questionnaires were developed for CAs and clinicians, assessing the scheme's successes and failures. Data analysis was carried out using MS Excel and SPSS. RESULTS AND DISCUSSION: Forty-nine CAs and 60 clinicians responded. CAs of all years were completing the higher-level role. They were perceived to improve continuity of care (74% CA agreement; 88% clinician agreement), reduce clinician workload (90% clinician agreement) and felt significantly more confident with practical and administrative tasks. Sixty-eight per cent of CAs and 72% of clinicians believed the role should be available to students before their final year.

The COVID‐19 risk in the Chinese option market

The COVID‐19 pandemic has increased fear of a financial market crash in China. We use an implied volatility slope measure, which proxies the cost of option protection against and therefore trader's fear of crash risk, using the Shanghai Shenzhen CSI 300 Index options. We show that this measure is positively related to new cases and deaths of the pandemic during the COVID‐19 outbreak in China. Option traders are willing to pay more for hedging downside tail risk as the pandemic worsens, and are no longer as concerned by news of cases and deaths after the lift of the lockdown.

Direct and Catalytic C-Glycosylation of Arenes: Expeditious Synthesis of the Remdesivir Nucleoside.

Since early 2020, scientists have strived to find an effective solution to fight SARS-CoV-2, in particular by developing reliable vaccines that inhibit the spread of the disease and repurposing drugs for combatting its effects on the human body. The antiviral prodrug Remdesivir is still the most widely used therapeutic during the early stages of the infection. However, the current synthetic routes rely on the use of protecting groups, air-sensitive reagents, and cryogenic conditions, thus impeding a cost-efficient supply to patients. We have, therefore, focused on the development of a straightforward, direct addition of (hetero)arenes to unprotected sugars. Here we report a silylium-catalyzed and completely stereoselective C-glycosylation that initially yields the open-chain polyols, which can be selectively cyclized to provide either the kinetic α-furanose or the thermodynamically favored ß-anomer. The method significantly expedites the synthesis of Remdesivir precursor GS-441524 after a subsequent Mn-catalyzed C-H oxidation and deoxycyanation.

Nachhaltige Strategien gegen die COVID-19-Pandemie in Deutschland im Winter 2021/2022 (preprint)

In this position paper, a large group of interdisciplinary experts outlines response strategies against the spread of SARS-CoV-2 in the winter of 2021/2022 in Germany. We review the current state of the COVID-19 pandemic, from incidence and vaccination efficacy to hospital capacity. Building on this situation assessment, we illustrate various possible scenarios for the winter, and detail the mechanisms and effectiveness of the non-pharmaceutical interventions, vaccination, and booster. With this assessment, we want to provide orientation for decision makers about the progress and mitigation of COVID-19.

Predicting the effects of COVID-19 related interventions in urban settings by combining activity-based modelling, agent-based simulation, and mobile phone data.

Epidemiological simulations as a method are used to better understand and predict the spreading of infectious diseases, for example of COVID-19. This paper presents an approach that combines a well-established approach from transportation modelling that uses person-centric data-driven human mobility modelling with a mechanistic infection model and a person-centric disease progression model. The model includes the consequences of different room sizes, air exchange rates, disease import, changed activity participation rates over time (coming from mobility data), masks, indoors vs. outdoors leisure activities, and of contact tracing. It is validated against the infection dynamics in Berlin (Germany). The model can be used to understand the contributions of different activity types to the infection dynamics over time. It predicts the effects of contact reductions, school closures/vacations, masks, or the effect of moving leisure activities from outdoors to indoors in fall, and is thus able to quantitatively predict the consequences of interventions. It is shown that these effects are best given as additive changes of the reproduction number R. The model also explains why contact reductions have decreasing marginal returns, i.e. the first 50% of contact reductions have considerably more effect than the second 50%. Our work shows that is is possible to build detailed epidemiological simulations from microscopic mobility models relatively quickly. They can be used to investigate mechanical aspects of the dynamics, such as the transmission from political decisions via human behavior to infections, consequences of different lockdown measures, or consequences of wearing masks in certain situations. The results can be used to inform political decisions.

Case Study on Detecting COVID-19 Health-Related Misinformation in Social Media (preprint)

COVID-19 pandemic has generated what public health officials called an infodemic of misinformation. As social distancing and stay-at-home orders came into effect, many turned to social media for socializing. This increase in social media usage has made it a prime vehicle for the spreading of misinformation. This paper presents a mechanism to detect COVID-19 health-related misinformation in social media following an interdisciplinary approach. Leveraging social psychology as a foundation and existing misinformation frameworks, we defined misinformation themes and associated keywords incorporated into the misinformation detection mechanism using applied machine learning techniques. Next, using the Twitter dataset, we explored the performance of the proposed methodology using multiple state-of-the-art machine learning classifiers. Our method shows promising results with at most 78% accuracy in classifying health-related misinformation versus true information using uni-gram-based NLP feature generations from tweets and the Decision Tree classifier. We also provide suggestions on alternatives for countering misinformation and ethical consideration for the study.

Non-Intrusive Assessment of COVID-19 Lockdown Follow-Up and Impact Using Credit Card Information: Case Study in Chile.

In this paper, we propose and validate with data extracted from the city of Santiago, capital of Chile, a methodology to assess the actual impact of lockdown measures based on the anonymized and geolocated data from credit card transactions. Using unsupervised Latent Dirichlet Allocation (LDA) semantic topic discovery, we identify temporal patterns in the use of credit cards that allow us to quantitatively assess the changes in the behavior of the people under the lockdown measures because of the COVID-19 pandemic. An unsupervised latent topic analysis uncovers the main patterns of credit card transaction activity that explain the behavior of the inhabitants of Santiago City. The approach is non-intrusive because it does not require the collaboration of people for providing the anonymous data. It does not interfere with the actual behavior of the people in the city; hence, it does not introduce any bias. We identify a strong downturn of the economic activity as measured by credit card transactions (down to 70%), and thus of the economic activity, in city sections (communes) that were subjected to lockdown versus communes without lockdown. This change in behavior is confirmed by independent data from mobile phone connectivity. The reduction of activity emerges before the actual lockdowns were enforced, suggesting that the population was spontaneously implementing the required measures for slowing virus propagation.