Modelling workplace contact networks: the effects of organizational structure, architecture, and reporting errors on epidemic predictions

Face-to-face social contacts are potentially important transmission routes for acute respiratory infections, and understanding the contact network can improve our ability to predict, contain, and control epidemics. Although workplaces are important settings for infectious disease transmission, few studies have collected workplace contact data and estimated workplace contact networks. We use contact diaries, architectural distance measures, and institutional structures to estimate social contact networks within a Swiss research institute. Some contact reports were inconsistent, indicating reporting errors. We adjust for this with a latent variable model, jointly estimating the true (unobserved) network of contacts and duration-specific reporting probabilities. We find that contact probability decreases with distance, and research group membership, role, and shared projects are strongly predictive of contact patterns. Estimated reporting probabilities were low only for 0-5 minute contacts. Adjusting for reporting error changed the estimate of the duration distribution, but did not change the estimates of covariate effects and had little effect on epidemic predictions. Our epidemic simulation study indicates that inclusion of network structure based on architectural and organizational structure data can improve the accuracy of epidemic forecasting models.Comment: 36 pages, 4 figure

Prioritätenliste und Kontingentberechnung : Pandemievorbereitung in der Schweiz

Eine Studie im Auftrag des Bundesamts für Gesundheit (BAG). Veröffentlichung in ZHAW digitalcollection mit freundlicher Genehmigung der ETH Zürich. 2. revidierte Fassung vom Oktober 2018Bei der Zuteilung knapper medizinischer Güter und Dienstleitungen stellen sich ethische Fragen: Wem, und gestützt auf welche Kriterien, sollen beispielsweise während einer Influenza Epidemie prioritär Impfdosen zugeordnet werden, wenn es zu Knappheiten kommt und nicht alle Bedürftigen Leistungen erhalten können? Dilemmata rund um die Zuteilung knapper Impfstoffe oder anderweitiger medikamentöser Prävention bzw. Behandlung von Infektionskrankheiten können jedoch nicht isoliert als Problem der Gesundheitsethik betrachtet werden. Vielmehr müssen medizinisch-biologische Faktoren, gesundheitsökonomische Faktoren und ethische Überlegungen aufeinander bezogen werden. Das Epidemiengesetz und die -verordnung regeln im Grundsatz die Zuteilung von Heilmitteln; der Pandemieplan Schweiz skizziert Priorisierungrichtlinien. Vorliegende Studie soll mögliche Priorisierungen im Pandemiefall konkretisieren und die Zuteilung auf die Kantone spezifizieren. Ziele sind entsprechend: (i) die Erarbeitung einer Prioritätenliste, die anerkannte medizinische und ethische Kriterien erfüllt; (ii) sowie die Festlegung der kantonalen Bedarfscharakteristika und Kontingente. Die Arbeit beinhaltet die Beschreibung: (1) der ethischen und medizinischen Grundlagen; (2) basierend darauf von Pandemie-Szenarien; (3) von Verteilungsalgorithmen mit Input von verschiedenen Priorisierungsprinzipien; sowie (4) der kantonalen Bedarfscharakteristika und Kontingente

Liste des priorités et calcul des contingents : préparation aux pandémies en Suisse

Une étude mandatée par l’Office fédéral de la santé publique. Publication dans ZHAW digitalcollection avec l'aimable autorisation de l'ETH Zurich. 2e version révisée d'octobre 2018.Des questions d’ordre éthique se posent lors de la distribution de substances et services médicaux en cas de pénurie: Qui, et sur la base de quels critères, doit par exemple recevoir en priorité des doses vaccinales pendant une épidémie de grippe, lorsque la pénurie guette et que toutes celles et ceux pour qui une vaccination se justifie ne peuvent recevoir une dose? Les dilemmes liés à la distribution de vaccins et d’autres moyens de prévention médicale ou de traitement des maladies infectieuses en cas de pénurie ne peuvent être considérés de manière isolée comme problème de l’éthique de la santé. Il s’agit bien plus de prendre en compte un ensemble de facteurs médico-biologiques, de facteurs liés aux coûts de la santé et de réflexions éthiques. La Loi et l’Ordonnance sur les épidémies réglementent en principe la distribution des substances thérapeutiques; Motivation et objectifs le Plan suisse de pandémie esquisse des directives pour l’élaboration de priorités. La présente étude vise à concrétiser de possibles ordres de priorité en case de pandémie et préciser la répartition entre les cantons. Les buts de l’étude sont donc: (i) l’élaboration d’une liste de priorités, qui satisfait à des critères médicaux et éthiques reconnus; (ii) ainsi que la définition de profils de besoins et contingents propres à chaque canton. L’étude contient la description (1) des bases éthiques et médicales ; (2) des scénarios de pandémies élaborés en fonction de ces dernières ; (3) d’algorithmes de distribution reflétant différents principes de priorités ; ainsi que (4) des profils de besoins et des contingents de chaque canton

Assessing the Dynamics and Control of Droplet- and Aerosol-Transmitted Influenza Using an Indoor Positioning System

There is increasing evidence that aerosol transmission is a major contributor to the spread of influenza. Despite this, virtually all studies assessing the dynamics and control of influenza assume that it is transmitted solely through direct contact and large droplets, requiring close physical proximity. Here, we use wireless sensors to measure simultaneously both the location and close proximity contacts in the population of a US high school. This dataset, highly resolved in space and time, allows us to model both droplet and aerosol transmission either in isolation or in combination. In particular, it allows us to computationally quantify the potential effectiveness of overlooked mitigation strategies such as improved ventilation that are available in the case of aerosol transmission. Our model suggests that recommendation-abiding ventilation could be as effective in mitigating outbreaks as vaccinating approximately half of the population. In simulations using empirical transmission levels observed in households, we find that bringing ventilation to recommended levels had the same mitigating effect as a vaccination coverage of 50% to 60%. Ventilation is an easy-to-implement strategy that has the potential to support vaccination efforts for effective control of influenza spread

Identifying English practices that are high antibiotic prescribers accounting for comorbidities and other legitimate medical reasons for variation

Background: Seeing one’s practice as a high antibiotic prescriber compared to general practices with similar patient populations can be one of the best motivators for change. Current comparisons are based on age-sex weighting of the practice population for expected prescribing rates (STAR-PU). Here, we investigate whether there is a need to additionally account for further potentially legitimate medical reasons for higher antibiotic prescribing. Methods: Publicly available data from 7,376 general practices in England between April 2014 and March 2015 were used. We built two different negative binomial regression models to compare observed versus expected antibiotic dispensing levels per practice: one including comorbidities as covariates and another with the addition of smoking prevalence and deprivation. We compared the ranking of practices in terms of items prescribed per STAR-PU according to i) conventional STAR-PU methodology, ii) observed vs expected prescribing levels using the comorbidity model, and iii) observed vs expected prescribing levels using the full model. Findings: The median number of antibiotic items prescribed per practice per STAR-PU was 1.09 (25th -75th percentile, 0.92-1.25). 1,133 practices (76.8% of 1,476) were consistently identified as being in the top 20% of high antibiotic prescribers. However, some practices that would be classified as high prescribers using the current STAR-PU methodology would not be classified as high prescribers if comorbidity was accounted for (n=269, 18.2%) and if additionally smoking prevalence and deprivation were accounted for (n=312, 21.1%). Interpretation: Current age-sex weighted comparisons of antibiotic prescribing rates in England are fair for many, but not all practices. This new metric that accounts for legitimate medical reasons for higher antibiotic prescribing may have more credibility among general practitioners and, thus, more likely to be acted upon

Actual versus 'ideal' antibiotic prescribing for common conditions in English primary care

Previous work based on guidelines and expert opinion identified 'ideal' prescribing proportions-the overall proportion of consultations that should result in an antibiotic prescription-for common infectious conditions. Here, actual condition-specific prescribing proportions in primary care in England were compared with ideal prescribing proportions identified by experts. All recorded consultations for common infectious conditions (cough, bronchitis, exacerbations of asthma or chronic obstructive pulmonary disease, sore throat, rhinosinusitis, otitis media, lower respiratory tract infection, upper respiratory tract infection, influenza-like illness, urinary tract infection, impetigo, acne, gastroenteritis) for 2013-15 were extracted from The Health Improvement Network (THIN) database. The proportions of consultations resulting in an antibiotic prescription were established, concentrating on acute presentations in patients without relevant comorbidities. These actual prescribing proportions were then compared with previously established 'ideal' proportions by condition. For most conditions, substantially higher proportions of consultations resulted in an antibiotic prescription than was deemed appropriate according to expert opinion. An antibiotic was prescribed in 41% of all acute cough consultations when experts advocated 10%. For other conditions the proportions were: bronchitis (actual 82% versus ideal 13%); sore throat (actual 59% versus ideal 13%); rhinosinusitis (actual 88% versus ideal 11%); and acute otitis media in 2- to 18-year-olds (actual 92% versus ideal 17%). Substantial variation between practices was found. This work has identified substantial overprescribing of antibiotics in English primary care, and highlights conditions where this is most pronounced, particularly in respiratory tract conditions

Understanding the gender gap in antibiotic prescribing:a cross-sectional analysis of English primary care

OBJECTIVES:To explore the causes of the gender gap in antibiotic prescribing, and to determine whether women are more likely than men to receive an antibiotic prescription per consultation. DESIGN:Cross-sectional analysis of routinely collected electronic medical records from The Health Improvement Network (THIN). SETTING:English primary care. PARTICIPANTS:Patients who consulted general practices registered with THIN between 2013 and 2015. PRIMARY AND SECONDARY OUTCOME MEASURES:Total antibiotic prescribing was measured in children (<19 years), adults (19-64 years) and the elderly (65+ years). For 12 common conditions, the number of adult consultations was measured, and the relative risk (RR) of being prescribed antibiotics when consulting as female or with comorbidity was estimated. RESULTS:Among 4.57 million antibiotic prescriptions observed in the data, female patients received 67% more prescriptions than male patients, and 43% more when excluding antibiotics used to treat urinary tract infection (UTI). These gaps were more pronounced in adult women (99% more prescriptions than men; 69% more when excluding UTI) than in children (9%; 0%) or the elderly (67%; 38%). Among adults, women accounted for 64% of consultations (62% among patients with comorbidity), but were not substantially more likely than men to receive an antibiotic prescription when consulting with common conditions such as cough (RR 1.01; 95% CI 1.00 to 1.02), sore throat (RR 1.01, 95% CI 1.00 to 1.01) and lower respiratory tract infection (RR 1.00, 95% CI 1.00 to 1.01). Exceptions were skin conditions: women were less likely to be prescribed antibiotics when consulting with acne (RR 0.67, 95% CI 0.66 to 0.69) or impetigo (RR 0.85, 95% CI 0.81 to 0.88). CONCLUSIONS:The gender gap in antibiotic prescribing can largely be explained by consultation behaviour. Although in most cases adult men and women are equally likely to be prescribed an antibiotic when consulting primary care, it is unclear whether or not they are equally indicated for antibiotic therapy

Explaining variation in antibiotic prescribing between general practices in the UK

Objectives:Primary care practices in England differ in antibiotic prescribing rates, and, anecdotally, prescribers justify high prescribing rates based on their individual case mix. The aim of this paper was to explore to what extent factors such as patient comorbidities explain this variation in antibiotic prescribing. Methods:Primary care consultation and prescribing data recorded in The Health Improvement Network (THIN) database in 2013 were used. Boosted regression trees (BRTs) and negative binomial regression (NBR) models were used to evaluate associations between predictors and antibiotic prescribing rates. The following variables were considered as potential predictors: various infection-related consultation rates, proportions of patients with comorbidities, proportion of patients with inhaled/systemic corticosteroids or immunosuppressive drugs, and demographic traits. Results:The median antibiotic prescribing rate was 65.6 (IQR 57.4-74.0) per 100 registered patients among 348 English practices. In the BRT model, consultation rates had the largest total relative influence on antibiotic prescribing rate (53.5%), followed by steroid and immunosuppressive drugs (31.6%) and comorbidities (12.2%). Only 21% of the deviance could be explained by an NBR model considering only comorbidities and age and gender, whereas 57% of the deviance could be explained by the model considering all variables. Conclusions:The majority of practice-level variation in antibiotic prescribing cannot be explained by variation in prevalence of comorbidities. Factors such as high consultation rates for respiratory tract infections and high prescribing rates for corticosteroids could explain much of the variation, and as such may be considered in determining a practice's potential to reduce prescribing

How should social mixing be measured: comparing web-based survey and sensor-based methods

Contact surveys and diaries have conventionally been used to measure contact networks in different settings for elucidating infectious disease transmission dynamics of respiratory infections. More recently, technological advances have permitted the use of wireless sensor devices, which can be worn by individuals interacting in a particular social context to record high resolution mixing patterns. To date, a direct comparison of these two different methods for collecting contact data has not been performed

Minimal models for spatially resolved population dynamics : applications to coexistence in multi – trait models

Spatial resolution is relevant for many processes in population dynamics because it may give rise to heterogeneity. Simulating the effect of space in two or three dimensions is computationally costly. Furthermore, in Euclidean space, the notion of heterogeneity is complemented by neighbourhood correlations. In this paper, we use an infinite-dimensional simplex as a minimal model of space in which heterogeneity is realized, but neighbourhood is trivial and study the coexistence of viral traits in a SIRS - model. As a function of the migration parameter, multiple regimes are observed. We further discuss the relevance of minimal models for decision support