Research gaps and priorities for quantitative microbial risk assessment (QMRA).

The coronavirus disease 2019 pandemic highlighted the need for more rapid and routine application of modeling approaches such as quantitative microbial risk assessment (QMRA) for protecting public health. QMRA is a transdisciplinary science dedicated to understanding, predicting, and mitigating infectious disease risks. To better equip QMRA researchers to inform policy and public health management, an Advances in Research for QMRA workshop was held to synthesize a path forward for QMRA research. We summarize insights from 41 QMRA researchers and experts to clarify the role of QMRA in risk analysis by (1) identifying key research needs, (2) highlighting emerging applications of QMRA; and (3) describing data needs and key scientific efforts to improve the science of QMRA. Key identified research priorities included using molecular tools in QMRA, advancing dose-response methodology, addressing needed exposure assessments, harmonizing environmental monitoring for QMRA, unifying a divide between disease transmission and QMRA models, calibrating and/or validating QMRA models, modeling co-exposures and mixtures, and standardizing practices for incorporating variability and uncertainty throughout the source-to-outcome continuum. Cross-cutting needs identified were to: develop a community of research and practice, integrate QMRA with other scientific approaches, increase QMRA translation and impacts, build communication strategies, and encourage sustainable funding mechanisms. Ultimately, a vision for advancing the science of QMRA is outlined for informing national to global health assessments, controls, and policies.

Aerosol and surface contamination assessment of a novel ventilated infectious aerosol containment device.

Healthcare personnels (HCPs) are at risk of respiratory infectious diseases during patient care activities. HCPs rely primarily on personal protective equipment to prevent pathogen exposures, but there is a need to develop alternative, or complementary control strategies, including engineering controls. The objective of this study was to evaluate the ability of the 3 designs (denoted D1A, D1B, and D2) of the University of Utah Containment Ventilation for Exposure Reduction (U-COVER), a protective barrier enclosure device to contain respirable aerosols when placed over a simulated patient. The 2 primary performance metrics were the percent reduction in: (i) the concentration of respirable aerosols in the simulated breathing zone of an HCP, and (ii) surface contamination outside the device, which were tested using salt aerosols and fluorescein aerosols, respectively. Briefly, salt or fluorescein aerosols were generated as though expelled by a prone patient under 3 conditions: (i) no device (control), (ii) with the device but without exhaust ventilation, and (iii) with the device with exhaust ventilation. Device D2 was also tested under simulated use conditions, in which cardboard "arms" were placed inside the device ports. All 3 device designs showed the ability to reduce particle concentrations in the simulated HCP breathing zone and on surfaces by >99% with exhaust ventilation compared to the control condition. Without exhaust ventilation, device performance was lower and highly variable. Under simulated use conditions, device D2 reduced particle concentrations in the simulated HCP breathing zone by ≥91% and on surfaces by >99% relative to control for all combinations of "arms" tested. The U-COVER device demonstrates excellent aerosol containment and warrants further testing with dynamic simulated or actual use conditions.

Surveillance of Mpox Cases Attending Sexual Health Services in England (SOMASS): design, implementation and initial findings from the SOMASS data collection tool, 2022.

OBJECTIVES: We aimed to design and implement a data collection tool to support the 2022 mpox (monkeypox) outbreak, and to describe clinical and epidemiological data from individuals with mpox attending sexual health services (SHSs) in England. METHODS: The UK Health Security Agency and the British Association for Sexual Health and HIV established the Surveillance of Mpox Cases Attending Sexual Health Services in England (SOMASS) system.Descriptive data were collected via a secure web-based data collection tool, completed by SHS clinicians following consultation with individuals with suspected mpox. Data were collected on patient demographics, clinical presentation and severity, exposures and behavioural characteristics. RESULTS: As of 17 November 2022, 276 SOMASS responses were submitted from 31 SHSs in England.Where recorded, most (245 of 261; 94%) individuals identified as gay, bisexual or men who have sex with men (GBMSM), of whom two-thirds were HIV negative (170 of 257; 66%) and taking HIV pre-exposure prophylaxis (87 of 140; 62%), with a median age of 37 years (IQR: 30-43). Where known, thirty-nine per cent (63 of 161) had a concurrent sexually transmitted infection (STI) at the time of their mpox diagnosis.For 46% of individuals (127 of 276), dermatological lesions were the initial symptom. Lesions were mostly asymmetrical and polymorphic, predominately affecting the genital area and perianal areas.Nine per cent (24 of 276) of individuals were hospitalised. We report an association between receptive anal intercourse among GBMSM and proctitis (27 of 115; 24% vs 7 of 130; 5%; p<0.0001), and the presence of perianal lesions as the primary lesion site (46 of 115; 40% vs 25 of 130; 19%; p=0.0003). CONCLUSIONS: We demonstrate multidisciplinary and responsive working to develop a robust data collection tool, which improved surveillance and strengthened the knowledge base. The SOMASS tool will allow data collection if mpox resurges in England. The model for developing the tool can be adapted to facilitate the preparedness and response to future STI outbreaks.

Health and Safety Regulations for COVID-19: A Policy Analysis.

The COVID-19 pandemic spurred some regulators in the USA to require occupational health and safety programs to prevent COVID-19 transmission in workplaces. The objective of this study was to describe such state and federal regulations enacted between January 2020 and January 2022. Regulations, including emergency temporary standards (ETS) and permanent standards, were identified through a search of Nexis Uni and Bloomberg Law and review of US OSHA websites and the Federal Register. Full texts were reviewed for regulatory scope, hazard and exposure definitions, determination of exposure or risk levels, and control strategies. Four state (California, Michigan, Virginia, and Oregon) and two federal regulations were identified. All regulations described respiratory aerosols as the primary source of SARS-CoV-2 and recognized person-to-person transmission by droplet, airborne, and contact routes. Only the US OSHA ETS for healthcare explicitly stated that inhalation of respiratory particles was the most likely method of COVID-19 transmission. The Virginia, Michigan, and Oregon regulations described different categories of risk defined by exposure frequency and duration or specific workplace activities. California described exposure as places and times when employees come into contact or congregate with other people. The US OSHA ETS for healthcare described exposure as involving close contact with suspected or confirmed COVID-19 patients. While all of the state regulations required strategies from across the hierarchy, only the Virginia regulations specifically incorporated the hierarchy of controls. Only the California and Virginia regulations explicitly linked control strategies to the transmission route, while Virginia demarcated control strategies by risk level. Oregon linked risk level to occupancy levels and physical distancing requirements and referred to the use of a layered approach for transmission control. The US OSHA ETS for healthcare defined droplet and airborne precautions but made no mention of the hierarchy of controls or risk levels. Respirators were discussed in most of the regulations. The first Michigan regulation explicitly required respirators appropriate to exposure risk. The California regulations noted that respirators protect the wearer while face coverings protect people around the wearer. These regulations offer insights for a permanent US OSHA infectious disease regulation, such as the need to consider a range of transmission modes including near- and far-range aerosol inhalation, endemic and novel pathogens, workplaces beyond healthcare settings, factors that contribute to exposure and risk, the hierarchy of controls, the role of vaccination, and the importance of written exposure assessment and infection prevention plans.

Community daytime noise pollution and socioeconomic differences in Chicago, IL.

Environmental noise may affect hearing and a variety of non-auditory disease processes. There is some evidence that, like other environmental hazards, noise may be differentially distributed across communities based on socioeconomic status. We aimed to a) predict daytime noise pollution levels and b) assess disparities in daytime noise exposure in Chicago, Illinois. We measured 5-minute daytime noise levels (Leq, 5-min) at 75 randomly selected sites in Chicago in March, 2019. Geographically-based variables thought to be associated with noise were obtained, and used to fit a noise land-use regression model to estimate the daytime environmental noise level at the centroid of the census blocks. Demographic and socioeconomic data were obtained from the City of Chicago for the 77 community areas, and associations with daytime noise levels were assessed using spatial autoregressive models. Mean sampled noise level (Leq, 5-min) was 60.6 dBA. The adjusted R2 and root mean square error of the noise land use regression model and the validation model were 0.60 and 4.67 dBA and 0.51 and 5.90 dBA, respectively. Nearly 75% of city blocks and 85% of city communities have predicted daytime noise level higher than 55 dBA. Of the socioeconomic variables explored, only community per capita income was associated with mean community predicted noise levels, and was highest for communities with incomes in the 2nd quartile. Both the noise measurements and land-use regression modeling demonstrate that Chicago has levels of environmental noise likely contributing to the total burden of environmental stressors. Noise is not uniformly distributed across Chicago; it is associated with proximity to roads and public transportation, and is higher among communities with mid-to-low incomes per capita, which highlights how socially and economically disadvantaged communities may be disproportionately impacted by this environmental exposure.

Respirators, face masks, and their risk reductions via multiple transmission routes for first responders within an ambulance.

First responders may have high SARS-CoV-2 infection risks due to working with potentially infected patients in enclosed spaces. The study objective was to estimate infection risks per transport for first responders and quantify how first responder use of N95 respirators and patient use of cloth masks can reduce these risks. A model was developed for two Scenarios: an ambulance transport with a patient actively emitting a virus in small aerosols that could lead to airborne transmission (Scenario 1) and a subsequent transport with the same respirator or mask use conditions, an uninfected patient; and remaining airborne SARS-CoV-2 and contaminated surfaces due to aerosol deposition from the previous transport (Scenario 2). A compartmental Monte Carlo simulation model was used to estimate the dispersion and deposition of SARS-CoV-2 and subsequent infection risks for first responders, accounting for variability and uncertainty in input parameters (i.e., transport duration, transfer efficiencies, SARS-CoV-2 emission rates from infected patients, etc.). Infection risk distributions and changes in concentration on hands and surfaces over time were estimated across sub-Scenarios of first responder respirator use and patient cloth mask use. For Scenario 1, predicted mean infection risks were reduced by 69%, 48%, and 85% from a baseline risk (no respirators or face masks used) of 2.9 × 10-2 ± 3.4 × 10-2 when simulated first responders wore respirators, the patient wore a cloth mask, and when first responders and the patient wore respirators or a cloth mask, respectively. For Scenario 2, infection risk reductions for these same Scenarios were 69%, 50%, and 85%, respectively (baseline risk of 7.2 × 10-3 ± 1.0 × 10-2). While aerosol transmission routes contributed more to viral dose in Scenario 1, our simulations demonstrate the ability of face masks worn by patients to additionally reduce surface transmission by reducing viral deposition on surfaces. Based on these simulations, we recommend the patient wear a face mask and first responders wear respirators, when possible, and disinfection should prioritize high use equipment.

Relative contributions of transmission routes for COVID-19 among healthcare personnel providing patient care.

The routes of COVID-19 transmission to healthcare personnel from infected patients is the subject of debate, but is critical to the selection of personal protective equipment. The objective of this paper was to explore the contributions of three transmission routes-contact, droplet, and inhalation-to the risk of occupationally acquired COVID-19 infection among healthcare personnel (HCP). The method was quantitative microbial risk assessment, and an exposure model, where possible model parameters were based on data specific to the SARS-CoV-2 virus when available. The key finding was that droplet and inhalation transmission routes predominate over the contact route, contributing 35%, 57%, and 8.2% of the probability of infection, on average, without use of personal protective equipment. On average, 80% of inhalation exposure occurs when HCP are near patients. The relative contribution of droplet and inhalation depends upon the emission of SARS-CoV-2 in respirable particles (<10 µm) through exhaled breath, and inhalation becomes predominant, on average, when emission exceeds five gene copies per min. The predicted concentration of SARS-CoV-2 in the air of the patient room is low (< 1 gene copy per m3 on average), and likely below the limit of quantification for many air sampling methods. The findings demonstrate the value of respiratory protection for HCP, and that field sampling may not be sensitive enough to verify the contribution of SARS-CoV-2 inhalation to the risk of occupationally acquired COVID-19 infection among healthcare personnel. The emission and infectivity of SARS-CoV-2 in respiratory droplets of different sizes is a critical knowledge gap for understanding and controlling COVID-19 transmission.

The cost of providing mechanical thrombectomy in the UK NHS: a micro-costing study.

INTRODUCTION: The clinical efficacy and cost-effectiveness of mechanical thrombectomy (MT) for the treatment of large vessel occlusion stroke is well established, but uncertainty remains around the true cost of delivering this treatment within the NHS. The aim of this study was to establish the cost of providing MT within the hyperacute phase of care and to explore differences in resources used and costs across different neuroscience centres in the UK. METHOD: This was a multicentre retrospective study using micro-costing methods to enable a precise assessment of the costs of MT from an NHS perspective. Data on resources used and their costs were collected from five UK neuroscience centres between 2015 and 2018. RESULTS: Data were collected on 310 patients with acute ischaemic stroke treated with MT. The mean total cost of providing MT and inpatient care within 24 hours was £10,846 (95% confidence interval (CI) 10,527-11,165) per patient. The main driver of cost was MT procedure costs, accounting for 73% (£7,943; 95% CI 7,649-8,237) of the total 24-hour cost. Costs were higher for patients treated under general anaesthesia (£11,048; standard deviation (SD) 2,654) than for local anaesthesia (£9,978; SD 2,654), mean difference £1,070 (95% CI 381-1,759; p=0.003); admission to an intensive care unit (ICU; £12,212; SD 3,028) against for admission elsewhere (£10,179; SD 2,415), mean difference £2,032 (95% CI 1,345-2,719; p<0001).The mean cost within 72 hours was £12,440 (95% CI 10,628-14,252). The total costs for the duration of inpatient care before discharge from a thrombectomy centre was £14,362 (95% CI 13,603-15,122). CONCLUSIONS: Major factors contributing to costs of MT for stroke include consumables and staff for intervention, use of general anaesthesia and ICU admissions. These findings can inform the reimbursement, provision and strategic planning of stroke services and aid future economic evaluations.

Experience of Chicagoland acute care hospitals in preparing for Ebola virus disease, 2014-2015.

During the 2014-2015 Ebola Virus Disease (EVD) outbreak, hospitals in the United States selected personal protective equipment (PPE) and trained healthcare personnel (HCP) in anticipation of receiving EVD patients. To improve future preparations for high-consequence infectious diseases, it was important to understand factors that affected PPE selection and training in the context of the EVD outbreak. Semistructured interviews were conducted with HCP involved with decision-making during EVD preparations at acute care hospitals in the Chicago, IL area to gather information about the PPE selection and training process. HCP who received training were surveyed about elements of training and their perceived impact and overall experience by email invitation. A total of 28 HCP from 15 hospitals were interviewed, and 55 HCP completed the survey. Factors affecting PPE selection included: changing guidance, vendor supply, performance evaluations, and perceived risk and comfort for HCP. Cost did not affect selection. PPE acquisition challenges were mitigated by: sharing within hospital networks, reusing PPE during training, and improvising with existing PPE stock. Selected PPE ensembles were similar across sites. Training included hands-on activities with trained observers, instructional videos, and simulations/drills, which were felt to increase HCP confidence. Many felt refresher training would be helpful. Hands-on training was perceived to be effective, but there is a need to establish the appropriate frequency of refresher training frequency to maintain competence. Lacking confidence in the CDC guidance, interviewed trainers described turning to other sources of information and developing independent PPE evaluation and selection. Response to emerging and/or high consequence infectious diseases would be enhanced by transparent, risk-based guidance for PPE selection and training that addresses protection level, ease of use, ensembles, and availability.

Estimate of incidence and cost of recreational waterborne illness on United States surface waters.

BACKGROUND: Activities such as swimming, paddling, motor-boating, and fishing are relatively common on US surface waters. Water recreators have a higher rate of acute gastrointestinal illness, along with other illnesses including respiratory, ear, eye, and skin symptoms, compared to non-water recreators. The quantity and costs of such illnesses are unknown on a national scale. METHODS: Recreational waterborne illness incidence and severity were estimated using data from prospective cohort studies of water recreation, reports of recreational waterborne disease outbreaks, and national water recreation statistics. Costs associated with medication use, healthcare provider visits, emergency department (ED) visits, hospitalizations, lost productivity, long-term sequelae, and mortality were aggregated. RESULTS: An estimated 4 billion surface water recreation events occur annually, resulting in an estimated 90 million illnesses nationwide and costs of $2.2- $3.7 billion annually (central 90% of values). Illnesses of moderate severity (visit to a health care provider or ED) were responsible for over 65% of the economic burden (central 90% of values: $1.4- $2.4 billion); severe illnesses (result in hospitalization or death) were responsible for approximately 8% of the total economic burden (central 90% of values: $108- $614 million). CONCLUSION: Recreational waterborne illnesses are associated with a substantial economic burden. These findings may be useful in cost-benefit analysis for water quality improvement and other risk reduction initiatives.

Estimated Costs of Sporadic Gastrointestinal Illness Associated with Surface Water Recreation: A Combined Analysis of Data from NEEAR and CHEERS Studies.

BACKGROUND: The burden of illness can be described by addressing both incidence and illness severity attributable to water recreation. Monetized as cost, attributable disease burden estimates can be useful for environmental management decisions. OBJECTIVES: We characterize the disease burden attributable to water recreation using data from two cohort studies using a cost of illness (COI) approach and estimate the largest drivers of the disease burden of water recreation. METHODS: Data from the NEEAR study, which evaluated swimming and wading in marine and freshwater beaches in six U.S. states, and CHEERS, which evaluated illness after incidental-contact recreation (boating, canoeing, fishing, kayaking, and rowing) on waterways in the Chicago area, were used to estimate the cost per case of gastrointestinal illness and costs attributable to water recreation. Data on health care and medication utilization and missed days of work or leisure were collected and combined with cost data to construct measures of COI. RESULTS: Depending on different assumptions, the cost of gastrointestinal symptoms attributable to water recreation are estimated to be $1,220 for incidental-contact recreation (range $338-$1,681) and $1,676 for swimming/wading (range $425-2,743) per 1,000 recreators. Lost productivity is a major driver of the estimated COI, accounting for up to 90% of total costs. CONCLUSIONS: Our estimates suggest gastrointestinal illness attributed to surface water recreation at urban waterways, lakes, and coastal marine beaches is responsible for costs that should be accounted for when considering the monetary impact of efforts to improve water quality. The COI provides more information than the frequency of illness, as it takes into account disease incidence, health care utilization, and lost productivity. Use of monetized disease severity information should be included in future studies of water quality and health. Citation: DeFlorio-Barker S, Wade TJ, Jones RM, Friedman LS, Wing C, Dorevitch S. 2017. Estimated costs of sporadic gastrointestinal illness associated with surface water recreation: a combined analysis of data from NEEAR and CHEERS Studies. Environ Health Perspect 125:215-222; http://dx.doi.org/10.1289/EHP130.

Modeling risk of occupational zoonotic influenza infection in swine workers.

Zoonotic transmission of influenza A virus (IAV) between swine and workers in swine production facilities may play a role in the emergence of novel influenza strains with pandemic potential. Guidelines to prevent transmission of influenza to swine workers have been developed but there is a need for evidence-based decision-making about protective measures such as respiratory protection. A mathematical model was applied to estimate the risk of occupational IAV exposure to swine workers by contact and airborne transmission, and to evaluate the use of respirators to reduce transmission. The Markov model was used to simulate the transport and exposure of workers to IAV in a swine facility. A dose-response function was used to estimate the risk of infection. This approach is similar to methods previously used to estimate the risk of infection in human health care settings. This study uses concentration of virus in air from field measurements collected during outbreaks of influenza in commercial swine facilities, and analyzed by polymerase chain reaction. It was found that spending 25 min working in a barn during an influenza outbreak in a swine herd could be sufficient to cause zoonotic infection in a worker. However, this risk estimate was sensitive to estimates of viral infectivity to humans. Wearing an excellent fitting N95 respirator reduced this risk, but with high aerosol levels the predicted risk of infection remained high under certain assumptions. The results of this analysis indicate that under the conditions studied, swine workers are at risk of zoonotic influenza infection. The use of an N95 respirator could reduce such risk. These findings have implications for risk assessment and preventive programs targeting swine workers. The exact level of risk remains uncertain, since our model may have overestimated the viability or infectivity of IAV. Additionally, the potential for partial immunity in swine workers associated with repeated low-dose exposures or from previous infection with other influenza strains was not considered. Further studies should explore these uncertainties.

Occupational exposures to influenza among healthcare workers in the United States.

The objective of this study is to estimate the annual number of occupational exposures to influenza among healthcare workers that result from providing direct and supportive care to influenza patients in acute care, home care and long-term care settings. Literature review was used to identify healthcare utilization for influenza, and worker activity patterns. This information was used, with Monte Carlo simulation, to tabulate the mean annual number of occupational exposures. Given a medium-sized epidemic with a 6% annual symptomatic influenza incidence proportion, the mean number of occupational exposures was estimated to be 81.8 million annually. Among the approximately 14 million healthcare workers, this corresponds to 5.8 exposures per worker annually, on average. Exposures, however, are likely concentrated among subsets of healthcare workers. Occupational exposures were most numerous in ambulatory care settings (38%), followed by long-term care facilities (30%) and home care settings (21%). The annual number of occupational exposures to influenza is high, but not every occupational exposure will result in infection. Some infection control activities, like patient isolation, can reduce the number of occupational exposures.

The clinical and cost-effectiveness of brief advice for excessive alcohol consumption among people attending sexual health clinics: a randomised controlled trial.

OBJECTIVES: To examine the clinical and cost-effectiveness of brief advice for excessive alcohol consumption among people who attend sexual health clinics. METHODS: Two-arm, parallel group, assessor blind, pragmatic, randomised controlled trial. 802 people aged 19 years or over who attended one of three sexual health clinics and were drinking excessively were randomised to either brief advice or control treatment. Brief advice consisted of feedback on alcohol and health, written information and an offer of an appointment with an Alcohol Health Worker. Control participants received a leaflet on health and lifestyle. The primary outcome was mean weekly alcohol consumption during the previous 90 days measured 6 months after randomisation. The main secondary outcome was unprotected sex during this period. RESULTS: Among the 402 randomised to brief advice, 397 (99%) received it. The adjusted mean difference in alcohol consumption at 6 months was -2.33 units per week (95% CI -4.69 to 0.03, p=0.053) among those in the active compared to the control arm of the trial. Unprotected sex was reported by 154 (53%) of those who received brief advice, and 178 (59%) controls (adjusted OR=0.89, 95% CI 0.63 to 1.25, p=0.496). There were no significant differences in costs between study groups at 6 months. CONCLUSIONS: Introduction of universal screening and brief advice for excessive alcohol use among people attending sexual health clinics does not result in clinically important reductions in alcohol consumption or provide a cost-effective use of resources. TRIAL REGISTRATION NUMBER: Current Controlled Trials ISRCTN 99963322.

Multiple imputation for assessment of exposures to drinking water contaminants: evaluation with the Atrazine Monitoring Program.

BACKGROUND: Drinking water may contain pollutants that harm human health. The frequency of pollutant monitoring may occur quarterly, annually, or less frequently, depending upon the pollutant, the pollutant concentration, and community water system. However, birth and other health outcomes are associated with narrow time-windows of exposure. Infrequent monitoring impedes linkage between water quality and health outcomes for epidemiological analyses. OBJECTIVES: To evaluate the performance of multiple imputation to fill in water quality values between measurements in community water systems (CWSs). METHODS: The multiple imputation method was implemented in a simulated setting using data from the Atrazine Monitoring Program (AMP, 2006-2009 in five Midwestern states). Values were deleted from the AMP data to leave one measurement per month. Four patterns reflecting drinking water monitoring regulations were used to delete months of data in each CWS: three patterns were missing at random and one pattern was missing not at random. Synthetic health outcome data were created using a linear and a Poisson exposure-response relationship with five levels of hypothesized association, respectively. The multiple imputation method was evaluated by comparing the exposure-response relationships estimated based on multiply imputed data with the hypothesized association. RESULTS: The four patterns deleted 65-92% months of atrazine observations in AMP data. Even with these high rates of missing information, our procedure was able to recover most of the missing information when the synthetic health outcome was included for missing at random patterns and for missing not at random patterns with low-to-moderate exposure-response relationships. CONCLUSIONS: Multiple imputation appears to be an effective method for filling in water quality values between measurements.

Benchmarking of a Markov multizone model of contaminant transport.

A Markov chain model previously applied to the simulation of advection and diffusion process of gaseous contaminants is extended to three-dimensional transport of particulates in indoor environments. The model framework and assumptions are described. The performance of the Markov model is benchmarked against simple conventional models of contaminant transport. The Markov model is able to replicate elutriation predictions of particle deposition with distance from a point source, and the stirred settling of respirable particles. Comparisons with turbulent eddy diffusion models indicate that the Markov model exhibits numerical diffusion in the first seconds after release, but over time accurately predicts mean lateral dispersion. The Markov model exhibits some instability with grid length aspect when turbulence is incorporated by way of the turbulent diffusion coefficient, and advection is present. However, the magnitude of prediction error may be tolerable for some applications and can be avoided by incorporating turbulence by way of fluctuating velocity (e.g. turbulence intensity).

Experimental evaluation of a Markov multizone model of particulate contaminant transport.

The performance of a Markov chain model of the three-dimensional transport of particulates in indoor environments is evaluated against experimentally measured supermicrometer particle deposition. Previously, the model was found to replicate the predictions of relatively simple particle transport and fate models; and this work represents the next step in model evaluation. The experiments modeled were (i) the release of polydispersed particles inside a building lobby, and (ii) the release of monodispersed fluorescein-tagged particles inside an experimental chamber under natural and forced mixing. The Markov model was able to reproduce the spatial patterns of particle deposition in both experiments, though the model predictions were sensitive to the parameterization of the particle release mechanism in the second experiment. Overall, the results indicate that the Markov model is a plausible tool for modeling the fate and transport of supermicrometer particles.

The clinical effectiveness and cost-effectiveness of brief intervention for excessive alcohol consumption among people attending sexual health clinics: a randomised controlled trial (SHEAR).

BACKGROUND: Excessive use of alcohol is associated with poor sexual health, but the clinical effectiveness and cost-effectiveness of brief alcohol intervention in this setting has not been investigated. OBJECTIVE: To examine the effects and cost-effectiveness of brief intervention for excessive alcohol consumption among people who attend sexual health clinics. DESIGN: A two-arm, parallel-group, single-blind, pragmatic, randomised controlled trial. Participants were randomised via an independent and remote telephone randomisation service using permuted blocks, stratified by clinic. SETTING: Study participants were recruited from three sexual health clinics in central and west London. PARTICIPANTS: For inclusion, potential participants had to be aged ≥ 19 years, drink excessive alcohol according to the Modified-Single Alcohol Screening Question, and be willing to provide written informed consent. We excluded those who were unable to communicate in English sufficiently well to complete the baseline assessment and those who could not provide contact details for the follow-up assessment. INTERVENTIONS: Brief advice was delivered by the treating clinician and comprised feedback on the possible health consequences of excessive drinking, a discussion of whether the participant's clinic attendance was linked to current alcohol use, written information on alcohol and health and an offer of an appointment with an alcohol health worker (AHW). Appointments with AHWs took place either in person or by telephone, lasted up to 30 minutes, and used the 'FRAMES' (Feedback about the adverse effects of alcohol, an emphasis on personal Responsibility for changing drinking behaviour, Advice about alcohol consumption, a Menu of options for further help and advice, an Empathic stance towards the patient and an emphasis on Self-efficacy) approach. Those in the control arm of the trial were offered a copy of a leaflet providing general information on health and lifestyle. MAIN OUTCOME MEASURES: Outcomes were assessed 6 months after randomisation. The primary outcome was mean weekly alcohol consumption during the previous 90 days. The main secondary outcome was unprotected sex during this period. RESULTS: Eight hundred and two people were recruited to the study of whom 592 (74%) were followed up 6 months later. Among 402 participants who were randomised to brief intervention, 397 (99%) received brief advice from the treating clinician and 81 (20%) also received input from an AHW. The adjusted mean difference in alcohol consumption after 6 months was -2.33 units per week [95% confidence interval (CI) -4.69 to 0.03 units per week, p = 0.053] for those in the active arm compared with the control arm. Unprotected sex was reported by 154 (53%) of those who received brief intervention and by 178 (59%) of controls (adjusted odds ratio 0.89, 95% CI 0.63 to 1.25, p = 0.496). Participants randomised to brief intervention reported drinking a mean of 10.4 units of alcohol per drinking day compared with 9.3 units among control participants (difference 1.10, 95% CI 0.29 to 1.96, p = 0.009). We found no statistically significant differences in other outcomes. Brief intervention (brief advice and input from an AHW) cost on average £12.60 per person to deliver and did not appear to provide a cost-effective use of resources. CONCLUSIONS: Introduction of universal screening and brief intervention for excessive alcohol use among people who attend sexual health clinics does not result in clinically important reductions in alcohol consumption or provide a cost-effective use of resources. While people attending sexual health clinics may want to achieve better sexual health, attempts to reduce alcohol consumption may not be seen by them as a necessary means of trying to achieve this aim. TRIAL REGISTRATION: This trial is registered as ISRCTN 99963322. FUNDING: This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 30. See the NIHR Journals Library website for further project information.

Community drinking water quality monitoring data: utility for public health research and practice.

CONTEXT: Environmental Public Health Tracking (EPHT) tracks the occurrence and magnitude of environmental hazards and associated adverse health effects over time. The EPHT program has formally expanded its scope to include finished drinking water quality. OBJECTIVES: Our objective was to describe the features, strengths, and limitations of using finished drinking water quality data from community water systems (CWSs) for EPHT applications, focusing on atrazine and nitrogen compounds in 8 Midwestern states. METHODS: Water quality data were acquired after meeting with state partners and reviewed and merged for analysis. RESULTS: Data and the coding of variables, particularly with respect to censored results (nondetects), were not standardized between states. Monitoring frequency varied between CWSs and between atrazine and nitrates, but this was in line with regulatory requirements. Cumulative distributions of all contaminants were not the same in all states (Peto-Prentice test P < .001). Atrazine results were highly censored in all states (76.0%-99.3%); higher concentrations were associated with increased measurement frequency and surface water as the CWS source water type. Nitrate results showed substantial state-to-state variability in censoring (20.5%-100%) and in associations between concentrations and the CWS source water type. CONCLUSIONS: Statistical analyses of these data are challenging due to high rates of censoring and uncertainty about the appropriateness of parametric assumptions for time-series data. Although monitoring frequency was consistent with regulations, the magnitude of time gaps coupled with uncertainty about CWS service areas may limit linkage with health outcome data.

A model to systematically employ professional judgment in the Bayesian Decision Analysis for a semiconductor industry exposure assessment.

Bayesian Decision Analysis (BDA) uses Bayesian statistics to integrate multiple types of exposure information and classify exposures within the exposure rating categorization scheme promoted in American Industrial Hygiene Association (AIHA) publications. Prior distributions for BDA may be developed from existing monitoring data, mathematical models, or professional judgment. Professional judgments may misclassify exposures. We suggest that a structured qualitative risk assessment (QLRA) method can provide consistency and transparency in professional judgments. In this analysis, we use a structured QLRA method to define prior distributions (priors) for BDA. We applied this approach at three semiconductor facilities in South Korea, and present an evaluation of the performance of structured QLRA for determination of priors, and an evaluation of occupational exposures using BDA. Specifically, the structured QLRA was applied to chemical agents in similar exposure groups to identify provisional risk ratings. Standard priors were developed for each risk rating before review of historical monitoring data. Newly collected monitoring data were used to update priors informed by QLRA or historical monitoring data, and determine the posterior distribution. Exposure ratings were defined by the rating category with the highest probability--i.e., the most likely. We found the most likely exposure rating in the QLRA-informed priors to be consistent with historical and newly collected monitoring data, and the posterior exposure ratings developed with QLRA-informed priors to be equal to or greater than those developed with data-informed priors in 94% of comparisons. Overall, exposures at these facilities are consistent with well-controlled work environments. That is, the 95th percentile of exposure distributions are ≤50% of the occupational exposure limit (OEL) for all chemical-SEG combinations evaluated; and are ≤10% of the limit for 94% of chemical-SEG combinations evaluated.