Effectiveness of BNT162b2 and ChAdOx1 against SARS-CoV-2 household transmission: a prospective cohort study in England.

Background: The ability of SARS-CoV-2 vaccines to protect against infection and onward transmission determines whether immunisation can control global circulation. We estimated the effectiveness of Pfizer-BioNTech mRNA vaccine (BNT162b2) and Oxford AstraZeneca adenovirus vector vaccine (ChAdOx1) vaccines against acquisition and transmission of the Alpha and Delta variants in a prospective household study in England. Methods: Households were recruited based on adult purported index cases testing positive after reverse transcription-quantitative (RT-q)PCR testing of oral-nasal swabs. Purported index cases and their household contacts took oral-nasal swabs on days 1, 3 and 7 after enrolment and a subset of the PCR-positive swabs underwent genomic sequencing conducted on a subset. We used Bayesian logistic regression to infer vaccine effectiveness against acquisition and transmission, adjusted for age, vaccination history and variant. Results: Between 2 February 2021 and 10 September 2021, 213 index cases and 312 contacts were followed up. After excluding households lacking genomic proximity (N=2) or with unlikely serial intervals (N=16), 195 households with 278 contacts remained, of whom 113 (41%) became PCR positive. Delta lineages had 1.53 times the risk (95% Credible Interval: 1.04 - 2.20) of transmission than Alpha; contacts older than 18 years old were 1.48 (1.20 - 1.91) and 1.02 (0.93 - 1.16) times more likely to acquire an Alpha or Delta infection than children. Effectiveness of two doses of BNT162b2 against transmission of Delta was 36% (-1%, 66%) and 49% (18%, 73%) for ChAdOx1, similar to their effectiveness for Alpha. Protection against infection with Alpha was higher than for Delta, 69% (9%, 95%) vs. 18% (-11%, 59%), respectively, for BNT162b2 and 24% (-41%, 72%) vs. 9% (-15%, 42%), respectively, for ChAdOx1. Conclusions: BNT162b2 and ChAdOx1 reduce transmission of the Delta variant from breakthrough infections in the household setting, although their protection against infection within this setting is low.

Optimal age targeting for pneumococcal vaccination in older adults; a modelling study.

Invasive pneumococcal disease (IPD) risk increases with age for older adults whereas the population size benefiting from pneumococcal vaccines and robustness of immunogenic response to vaccination decline. We estimate how demographics, vaccine efficacy/effectiveness (VE), and waning VE impact on optimal age for a single-dose pneumococcal vaccination. Age- and vaccine-serotype-specific IPD cases from routine surveillance of adults ≥ 55 years old (y), ≥ 4-years after infant-pneumococcal vaccine introduction and before 2020, and VE data from prior studies were used to estimate IPD incidence and waning VE which were then combined in a cohort model of vaccine impact. In Brazil, Malawi, South Africa and England 51, 51, 54 and 39% of adults older than 55 y were younger than 65 years old, with a smaller share of annual IPD cases reported among < 65 years old in England (4,657; 20%) than Brazil (186; 45%), Malawi (4; 63%), or South Africa (134, 48%). Vaccination at 55 years in Brazil, Malawi, and South Africa, and at 70 years in England had the greatest potential for IPD prevention. Here, we show that in low/middle-income countries, pneumococcal vaccines may prevent a substantial proportion of residual IPD burden if administered earlier in adulthood than is typical in high-income countries.

Ultrafine particle exposure and biomarkers of effect on small airways in children.

The small size and large surface area of ultrafine particles (UFP) enhance their ability to deposit in the lung periphery and their reactivity. The Ultrafine Particles from Traffic Emissions and Children's Health (UPTECH) cross-sectional study was conducted in 8-11-year-old schoolchildren attending 25 primary (elementary) schools, randomly selected from the Brisbane Metropolitan Area, Queensland, Australia. Main study findings outlined indirect evidence of distal airway deposition (raised C reactive protein) but as yet, there is no direct evidence in the literature of effects of UFP exposure on peripheral airway function. We present further UPTECH study data from two sensitive peripheral airway function tests, Oscillometry and Multiple Breath Nitrogen Washout (MBNW), performed in 577 and 627 children (88% and 96% of UPTECH study cohort) respectively: mean(SD) age 10.1(0.9) years, 46% male, with 50% atopy and 14% current asthma. Bayesian generalised linear mixed effects regression models were used to estimate the effect of UFP particle number count (PNC) exposure on key oscillometry (airway resistance, (Rrs), and reactance, (Xrs)) and MBNW (lung clearance index, (LCI) and functional residual capacity, (FRC)) indices. We adjusted for age, sex, and height, and potential confounders including socio-economic disadvantage, PM2.5 and NO2 exposure. All models contained an interaction term between UFP PNC exposure and atopy, allowing estimation of the effect of exposure on non-atopic and atopic students. Increasing UFP PNC was associated with greater lung stiffness as evidenced by a decrease in Xrs [mean (95% credible interval) -1.63 (-3.36 to -0.05)%] per 1000#.cm-3]. It was also associated with greater lung stiffness (decrease in Xrs) in atopic subjects across all models [mean change ranging from -2.06 to -2.40% per 1000#.cm-3]. A paradoxical positive effect was observed for Rrs across all models [mean change ranging from -1.55 to -1.70% per 1000#.cm-3] (decreases in Rrs indicating an increase in airway calibre), which was present for both atopic and non-atopic subjects. No effects on MBNW indices were observed. In conclusion, a modest detrimental effect of UFP on peripheral airway function among atopic subjects, as assessed by respiratory system reactance, was observed extending the main UPTECH study findings which reported a positive association with a biomarker for systemic inflammation, C-reactive protein (CRP). Further studies are warranted to explore the pathophysiological mechanisms underlying increased respiratory stiffness, and whether it persists through to adolescence and adulthood.

Using trained dogs and organic semi-conducting sensors to identify asymptomatic and mild SARS-CoV-2 infections: an observational study.

BACKGROUND: A rapid, accurate, non-invasive diagnostic screen is needed to identify people with SARS-CoV-2 infection. We investigated whether organic semi-conducting (OSC) sensors and trained dogs could distinguish between people infected with asymptomatic or mild symptoms, and uninfected individuals, and the impact of screening at ports-of-entry. METHODS: Odour samples were collected from adults, and SARS-CoV-2 infection status confirmed using RT-PCR. OSC sensors captured the volatile organic compound (VOC) profile of odour samples. Trained dogs were tested in a double-blind trial to determine their ability to detect differences in VOCs between infected and uninfected individuals, with sensitivity and specificity as the primary outcome. Mathematical modelling was used to investigate the impact of bio-detection dogs for screening. RESULTS: About, 3921 adults were enrolled in the study and odour samples collected from 1097 SARS-CoV-2 infected and 2031 uninfected individuals. OSC sensors were able to distinguish between SARS-CoV-2 infected individuals and uninfected, with sensitivity from 98% (95% CI 95-100) to 100% and specificity from 99% (95% CI 97-100) to 100%. Six dogs were able to distinguish between samples with sensitivity ranging from 82% (95% CI 76-87) to 94% (95% CI 89-98) and specificity ranging from 76% (95% CI 70-82) to 92% (95% CI 88-96). Mathematical modelling suggests that dog screening plus a confirmatory PCR test could detect up to 89% of SARS-CoV-2 infections, averting up to 2.2 times as much transmission compared to isolation of symptomatic individuals only. CONCLUSIONS: People infected with SARS-CoV-2, with asymptomatic or mild symptoms, have a distinct odour that can be identified by sensors and trained dogs with a high degree of accuracy. Odour-based diagnostics using sensors and/or dogs may prove a rapid and effective tool for screening large numbers of people.Trial Registration NCT04509713 (clinicaltrials.gov).

Strategies to reduce the risk of SARS-CoV-2 importation from international travellers: modelling estimations for the United Kingdom, July 2020.

BackgroundTo mitigate SARS-CoV-2 transmission risks from international air travellers, many countries implemented a combination of up to 14 days of self-quarantine upon arrival plus PCR testing in the early stages of the COVID-19 pandemic in 2020.AimTo assess the effectiveness of quarantine and testing of international travellers to reduce risk of onward SARS-CoV-2 transmission into a destination country in the pre-COVID-19 vaccination era.MethodsWe used a simulation model of air travellers arriving in the United Kingdom from the European Union or the United States, incorporating timing of infection stages while varying quarantine duration and timing and number of PCR tests.ResultsQuarantine upon arrival with a PCR test on day 7 plus a 1-day delay for results can reduce the number of infectious arriving travellers released into the community by a median 94% (95% uncertainty interval (UI): 89-98) compared with a no quarantine/no test scenario. This reduction is similar to that achieved by a 14-day quarantine period (median > 99%; 95% UI: 98-100). Even shorter quarantine periods can prevent a substantial amount of transmission; all strategies in which travellers spend at least 5 days (mean incubation period) in quarantine and have at least one negative test before release are highly effective (median reduction 89%; 95% UI: 83-95)).ConclusionThe effect of different screening strategies impacts asymptomatic and symptomatic individuals differently. The choice of an optimal quarantine and testing strategy for unvaccinated air travellers may vary based on the number of possible imported infections relative to domestic incidence.

Quarantine and testing strategies in contact tracing for SARS-CoV-2: a modelling study.

BACKGROUND: In most countries, contacts of confirmed COVID-19 cases are asked to quarantine for 14 days after exposure to limit asymptomatic onward transmission. While theoretically effective, this policy places a substantial social and economic burden on both the individual and wider society, which might result in low adherence and reduced policy effectiveness. We aimed to assess the merit of testing contacts to avert onward transmission and to replace or reduce the length of quarantine for uninfected contacts. METHODS: We used an agent-based model to simulate the viral load dynamics of exposed contacts, and their potential for onward transmission in different quarantine and testing strategies. We compared the performance of quarantines of differing durations, testing with either PCR or lateral flow antigen (LFA) tests at the end of quarantine, and daily LFA testing without quarantine, against the current 14-day quarantine strategy. We also investigated the effect of contact tracing delays and adherence to both quarantine and self-isolation on the effectiveness of each strategy. FINDINGS: Assuming moderate levels of adherence to quarantine and self-isolation, self-isolation on symptom onset alone can prevent 37% (95% uncertainty interval [UI] 12-56) of onward transmission potential from secondary cases. 14 days of post-exposure quarantine reduces transmission by 59% (95% UI 28-79). Quarantine with release after a negative PCR test 7 days after exposure might avert a similar proportion (54%, 95% UI 31-81; risk ratio [RR] 0·94, 95% UI 0·62-1·24) to that of the 14-day quarantine period, as would quarantine with a negative LFA test 7 days after exposure (50%, 95% UI 28-77; RR 0·88, 0·66-1·11) or daily testing without quarantine for 5 days after tracing (50%, 95% UI 23-81; RR 0·88, 0·60-1·43) if all tests are returned negative. A stronger effect might be possible if individuals isolate more strictly after a positive test and if contacts can be notified faster. INTERPRETATION: Testing might allow for a substantial reduction in the length of, or replacement of, quarantine with a small excess in transmission risk. Decreasing test and trace delays and increasing adherence will further increase the effectiveness of these strategies. Further research is required to empirically evaluate the potential costs (increased transmission risk, false reassurance) and benefits (reduction in the burden of quarantine, increased adherence) of such strategies before adoption as policy. FUNDING: National Institute for Health Research, UK Research and Innovation, Wellcome Trust, EU Horizon 2021, and the Bill & Melinda Gates Foundation.

COVID-19 length of hospital stay: a systematic review and data synthesis.

BACKGROUND: The COVID-19 pandemic has placed an unprecedented strain on health systems, with rapidly increasing demand for healthcare in hospitals and intensive care units (ICUs) worldwide. As the pandemic escalates, determining the resulting needs for healthcare resources (beds, staff, equipment) has become a key priority for many countries. Projecting future demand requires estimates of how long patients with COVID-19 need different levels of hospital care. METHODS: We performed a systematic review of early evidence on length of stay (LoS) of patients with COVID-19 in hospital and in ICU. We subsequently developed a method to generate LoS distributions which combines summary statistics reported in multiple studies, accounting for differences in sample sizes. Applying this approach, we provide distributions for total hospital and ICU LoS from studies in China and elsewhere, for use by the community. RESULTS: We identified 52 studies, the majority from China (46/52). Median hospital LoS ranged from 4 to 53 days within China, and 4 to 21 days outside of China, across 45 studies. ICU LoS was reported by eight studies-four each within and outside China-with median values ranging from 6 to 12 and 4 to 19 days, respectively. Our summary distributions have a median hospital LoS of 14 (IQR 10-19) days for China, compared with 5 (IQR 3-9) days outside of China. For ICU, the summary distributions are more similar (median (IQR) of 8 (5-13) days for China and 7 (4-11) days outside of China). There was a visible difference by discharge status, with patients who were discharged alive having longer LoS than those who died during their admission, but no trend associated with study date. CONCLUSION: Patients with COVID-19 in China appeared to remain in hospital for longer than elsewhere. This may be explained by differences in criteria for admission and discharge between countries, and different timing within the pandemic. In the absence of local data, the combined summary LoS distributions provided here can be used to model bed demands for contingency planning and then updated, with the novel method presented here, as more studies with aggregated statistics emerge outside China.

The effect of travel restrictions on the geographical spread of COVID-19 between large cities in China: a modelling study.

BACKGROUND: To contain the spread of COVID-19, a cordon sanitaire was put in place in Wuhan prior to the Lunar New Year, on 23 January 2020. We assess the efficacy of the cordon sanitaire to delay the introduction and onset of local transmission of COVID-19 in other major cities in mainland China. METHODS: We estimated the number of infected travellers from Wuhan to other major cities in mainland China from November 2019 to February 2020 using previously estimated COVID-19 prevalence in Wuhan and publicly available mobility data. We focused on Beijing, Chongqing, Hangzhou, and Shenzhen as four representative major cities to identify the potential independent contribution of the cordon sanitaire and holiday travel. To do this, we simulated outbreaks generated by infected arrivals in these destination cities using stochastic branching processes. We also modelled the effect of the cordon sanitaire in combination with reduced transmissibility scenarios to simulate the effect of local non-pharmaceutical interventions. RESULTS: We find that in the four cities, given the potentially high prevalence of COVID-19 in Wuhan between December 2019 and early January 2020, local transmission may have been seeded as early as 1-8 January 2020. By the time the cordon sanitaire was imposed, infections were likely in the thousands. The cordon sanitaire alone did not substantially affect the epidemic progression in these cities, although it may have had some effect in smaller cities. Reduced transmissibility resulted in a notable decrease in the incidence of infection in the four studied cities. CONCLUSIONS: Our results indicate that sustained transmission was likely occurring several weeks prior to the implementation of the cordon sanitaire in four major cities of mainland China and that the observed decrease in incidence was likely attributable to other non-pharmaceutical, transmission-reducing interventions.

Effectiveness of interventions targeting air travellers for delaying local outbreaks of SARS-CoV-2.

BACKGROUND: We evaluated if interventions aimed at air travellers can delay local severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) community transmission in a previously unaffected country. METHODS: We simulated infected air travellers arriving into countries with no sustained SARS-CoV-2 transmission or other introduction routes from affected regions. We assessed the effectiveness of syndromic screening at departure and/or arrival and traveller sensitisation to the COVID-2019-like symptoms with the aim to trigger rapid self-isolation and reporting on symptom onset to enable contact tracing. We assumed that syndromic screening would reduce the number of infected arrivals and that traveller sensitisation reduces the average number of secondary cases. We use stochastic simulations to account for uncertainty in both arrival and secondary infections rates, and present sensitivity analyses on arrival rates of infected travellers and the effectiveness of traveller sensitisation. We report the median expected delay achievable in each scenario and an inner 50% interval. RESULTS: Under baseline assumptions, introducing exit and entry screening in combination with traveller sensitisation can delay a local SARS-CoV-2 outbreak by 8 days (50% interval: 3-14 days) when the rate of importation is 1 infected traveller per week at time of introduction. The additional benefit of entry screening is small if exit screening is effective: the combination of only exit screening and traveller sensitisation can delay an outbreak by 7 days (50% interval: 2-13 days). In the absence of screening, with less effective sensitisation, or a higher rate of importation, these delays shrink rapidly to <4 days. CONCLUSION: Syndromic screening and traveller sensitisation in combination may have marginally delayed SARS-CoV-2 outbreaks in unaffected countries.

Using virtual reality and thermal imagery to improve statistical modelling of vulnerable and protected species.

Biodiversity loss and sparse observational data mean that critical conservation decisions may be based on little to no information. Emerging technologies, such as airborne thermal imaging and virtual reality, may facilitate species monitoring and improve predictions of species distribution. Here we combined these two technologies to predict the distribution of koalas, specialized arboreal foliovores facing population declines in many parts of eastern Australia. For a study area in southeast Australia, we complemented ground-survey records with presence and absence observations from thermal-imagery obtained using Remotely-Piloted Aircraft Systems. These field observations were further complemented with information elicited from koala experts, who were immersed in 360-degree images of the study area. The experts were asked to state the probability of habitat suitability and koala presence at the sites they viewed and to assign each probability a confidence rating. We fit logistic regression models to the ground survey data and the ground plus thermal-imagery survey data and a Beta regression model to the expert elicitation data. We then combined parameter estimates from the expert-elicitation model with those from each of the survey models to predict koala presence and absence in the study area. The model that combined the ground, thermal-imagery and expert-elicitation data substantially reduced the uncertainty around parameter estimates and increased the accuracy of classifications (koala presence vs absence), relative to the model based on ground-survey data alone. Our findings suggest that data elicited from experts using virtual reality technology can be combined with data from other emerging technologies, such as airborne thermal-imagery, using traditional statistical models, to increase the information available for species distribution modelling and the conservation of vulnerable and protected species.

Characteristics of school children's personal exposure to ultrafine particles in Heshan, Pearl River Delta, China - A pilot study.

BACKGROUND: There is a significant lack of scientific knowledge on population exposure to ultrafine particles (UFP) in China to date. This paper quantifies and characterises school children's personal UFP exposure and exposure intensity against their indoor and outdoor activities during a school day (home, school and commuting) in the city of Heshan within the Pearl River Delta (PRD) region, southern China. METHODS: Time-series of UFP number concentrations and average size were measured over 24 h for 24 children (9-13 years old), using personal monitors over two weeks in April 2016. Time-activity diaries and a questionnaire on the general home environment and potential sources of particles at home were also collected for each participating child. The analysis included concurrently measured size distributions of ambient UFP at a nearby fixed reference site (Heshan Supersite). RESULTS: Hourly average UFP concentrations exhibited three peaks in the morning, midday and evening. Time spent indoors at home was found to have the highest average exposure (1.26 × 104 cm-3 during sleeping) and exposure intensity (2.41). While there is always infiltration of outdoor particles indoors (from nearby traffic and general urban background sources), indoor exposure at home was significantly higher than outdoor exposure. Based on the collected questionnaire data, this was considered to be driven predominantly by adults smoking and the use of mosquito repellent incense during the night. Outdoor activities at school were associated with the lowest average exposure (6.87 × 102 cm-3) and exposure intensity (0.52). CONCLUSION: Despite the small sample size, this study characterised, for the first time, children's personal UFP exposure in a city downwind of major pollution sources of the PRD region in China. Particularly, the results highlighted the impact of smoking at home on children's exposure. While the study could not apportion the specific contributions of second hand-smoking and mosquito coil burning, considering the prevalence of smokers among the parents who smoke at home, smoking is a very significant factor. Exposure to second-hand smoke is avoidable, and these findings point out to the crucial role of government authorities and public health educators in engaging with the community on the role of air quality on health, and the severity of the impact of second-hand smoke on children's health.

Evaluating health facility access using Bayesian spatial models and location analysis methods.

BACKGROUND: Floating catchment methods have recently been applied to identify priority regions for Automated External Defibrillator (AED) deployment, to aid in improving Out of Hospital Cardiac Arrest (OHCA) survival. This approach models access as a supply-to-demand ratio for each area, targeting areas with high demand and low supply for AED placement. These methods incorporate spatial covariates on OHCA occurrence, but do not provide precise AED locations, which are critical to the initial intent of such location analysis research. Exact AED locations can be determined using optimisation methods, but they do not incorporate known spatial risk factors for OHCA, such as income and demographics. Combining these two approaches would evaluate AED placement impact, describe drivers of OHCA occurrence, and identify areas that may not be appropriately covered by AED placement strategies. There are two aims in this paper. First, to develop geospatial models of OHCA that account for and display uncertainty. Second, to evaluate the AED placement methods using geospatial models of accessibility. We first identify communities with the greatest gap between demand and supply for allocating AEDs. We then use this information to evaluate models for precise AED location deployment. METHODS: Case study data set consisted of 2802 OHCA events and 719 AEDs. Spatial OHCA occurrence was described using a geospatial model, with possible spatial correlation accommodated by introducing a conditional autoregressive (CAR) prior on the municipality-level spatial random effect. This model was fit with Integrated Nested Laplacian Approximation (INLA), using covariates for population density, proportion male, proportion over 65 years, financial strength, and the proportion of land used for transport, commercial, buildings, recreation, and urban areas. Optimisation methods for AED locations were applied to find the top 100 AED placement locations. AED access was calculated for current access and 100 AED placements. Priority rankings were then given for each area based on their access score and predicted number of OHCA events. RESULTS: Of the 2802 OHCA events, 64.28% occurred in rural areas, and 35.72% in urban areas. Additionally, over 70% of individuals were aged over 65. Supply of AEDs was less than demand in most areas. Priority regions for AED placement were identified, and access scores were evaluated for AED placement methodology by ranking the access scores and the predicted OHCA count. AED placement methodology placed AEDs in areas with the highest priority, but placed more AEDs in areas with more predicted OHCA events in each grid cell. CONCLUSION: The methods in this paper incorporate OHCA spatial risk factors and OHCA coverage to identify spatial regions most in need of resources. These methods can be used to help understand how AED allocation methods affect OHCA accessibility, which is of significant practical value for communities when deciding AED placements.

Serostatus testing and dengue vaccine cost-benefit thresholds.

The World Health Organization (WHO) currently recommends pre-screening for past infection prior to administration of the only licensed dengue vaccine, CYD-TDV. Using a threshold modelling analysis, we identify settings where this guidance prohibits positive net-benefits, and are thus unfavourable. Generally, however, our model shows test-then-vaccinate strategies can improve CYD-TDV economic viability: effective testing reduces unnecessary vaccination costs while increasing health benefits. With sufficiently low testing cost, those trends outweigh additional screening costs, expanding the range of settings with positive net-benefits. This work highlights two aspects for further analysis of test-then-vaccinate strategies. We found that starting routine testing at younger ages could increase benefits; if real tests are shown to sufficiently address safety concerns, the manufacturer, regulators and WHO should revisit guidance restricting use to 9-years-and-older recipients. We also found that repeat testing could improve return-on-investment (ROI), despite increasing intervention costs. Thus, more detailed analyses should address questions on repeat testing and testing periodicity, in addition to real test sensitivity and specificity. Our results follow from a mathematical model relating ROI to epidemiology, intervention strategy, and costs for testing, vaccination and dengue infections. We applied this model to a range of strategies, costs and epidemiological settings pertinent to CYD-TDV. However, general trends may not apply locally, so we provide our model and analyses as an R package available via CRAN, denvax. To apply to their setting, decision-makers need only local estimates of age-specific seroprevalence and costs for secondary infections.

Health care worker vaccination against Ebola: Vaccine acceptance and employment duration in Sierra Leone.

Health care workers (HCW) are at high risk of Ebola virus disease (EVD) infection during epidemics and may contribute to onward transmission, and therefore HCW-targeted prophylactic vaccination strategies are being considered as interventions. To assess the feasibility of preventive HCW vaccination, we conducted a pilot survey on staff turnover and vaccine acceptance amongst 305 HCW in Freetown and Kambia districts of Sierra Leone. Multivariable logistic regression demonstrated which demographic and behavioural factors were associated with acceptance of a hypothetical new vaccine. We quantified the duration of employment of HCW, and used multivariable gamma regression to detect associations with duration of employment in current or any health care position. Finally, we simulated populations of HCW, to determine the likely future immunisation coverage amongst HCW based on our estimates of vaccine acceptance and employment duration. Most HCW we surveyed had a positive opinion of EVD vaccination (76.3%). We found that being a volunteer HCW (vs being on the government payroll) was associated with increased vaccine acceptance. We found that HCW have stable employment, with a mean duration of employment in the health sector of 10.9 years (median 8.0 years). Older age and being on the government payroll (vs volunteer HCW) were associated with a longer duration of employment in the health sector. Assuming a single vaccine campaign, with 76.3% vaccine acceptance, 100% vaccine efficacy and no waning of vaccine-induced protection, immunisation coverage was sustained over 50% until 6 years after a vaccination campaign. If vaccine-induced immunity wanes at 10% per year, then the immunisation coverage among HCW would fall below 50% after 3 years. Vaccinating HCW against EVD could be feasible as employment appeared stable and vaccine acceptance high. However, even with high vaccine efficacy and long-lasting immunity, repeated campaigns or vaccination at employment start may be necessary to maintain high coverage.

Investigations into factors affecting personal exposure to particles in urban microenvironments using low-cost sensors.

Epidemiological studies have linked outdoor PM2.5 concentrations to a range of health effects, although people spend most of the time indoors. To better understand how individuals' exposure vary as they move between different indoor and outdoor microenvironments, our study investigated personal PM2.5 exposure and exposure intensity of 14 adult volunteers over one week (five weekdays and one weekend), using low-cost personal monitors, recording PM2.5 concentrations in 5 min intervals. Further, the study evaluated community perception of air pollution exposure during the recruitment and engagement with the volunteers. We found that people with tertiary education across all ages had greater interest in participating, with younger people being interested regardless of the level of education. The derived exposures and exposure intensities differed between weekdays and the weekend due to larger variations in individuals' daily routines. In general, time spent at home and engaged in indoor activities was associated with the highest personal PM2.5 exposure and exposure intensity on both, week and weekend days, implying the significance of both duration of the exposure and the indoor PM2.5 concentrations. The results showed no relationship between personal exposures and indoor characteristics of home (ventilation, building age and cooktop), which are expected to be due to the study's small sample size. The observed PM2.5 > 10 µg m-3 were significantly higher for distances <50 m to the roads for both major and minor roads, and were observed in areas with <16% open space, which were also close to a major road.

Joint-level energetics differentiate isoinertial from speed-power resistance training-a Bayesian analysis.

BACKGROUND: There is convincing evidence for the benefits of resistance training on vertical jump improvements, but little evidence to guide optimal training prescription. The inability to detect small between modality effects may partially reflect the use of ANOVA statistics. This study represents the results of a sub-study from a larger project investigating the effects of two resistance training methods on load carriage running energetics. Bayesian statistics were used to compare the effectiveness of isoinertial resistance against speed-power training to change countermovement jump (CMJ) and squat jump (SJ) height, and joint energetics. METHODS: Active adults were randomly allocated to either a six-week isoinertial (n = 16; calf raises, leg press, and lunge), or a speed-power training program (n = 14; countermovement jumps, hopping, with hip flexor training to target pre-swing running energetics). Primary outcome variables included jump height and joint power. Bayesian mixed modelling and Functional Data Analysis were used, where significance was determined by a non-zero crossing of the 95% Bayesian Credible Interval (CrI). RESULTS: The gain in CMJ height after isoinertial training was 1.95 cm (95% CrI [0.85-3.04] cm) greater than the gain after speed-power training, but the gain in SJ height was similar between groups. In the CMJ, isoinertial training produced a larger increase in power absorption at the hip by a mean 0.018% (equivalent to 35 W) (95% CrI [0.007-0.03]), knee by 0.014% (equivalent to 27 W) (95% CrI [0.006-0.02]) and foot by 0.011% (equivalent to 21 W) (95% CrI [0.005-0.02]) compared to speed-power training. DISCUSSION: Short-term isoinertial training improved CMJ height more than speed-power training. The principle adaptive difference between training modalities was at the level of hip, knee and foot power absorption.

Identification of technical problems affecting performance of DustTrak DRX aerosol monitors.

The TSI DustTrak Aerosol Monitor is a portable real-time instrument widely used for particulate matter (PM) mass concentrations monitoring. The aim of this work is to report on issues that have arisen from the use of the latest generation models DustTrak DRX (8533 and 8534) in the BREATHE, UPTECH and IMPROVE projects that can compromise data quality. The main issue we encountered was the occurrence of sudden artefact jumps in PM concentration, which can involve an increase from a few to some hundreds of µg·m-3. These artefact jumps can sometimes be easily recognised ("obvious jump"), while others can be difficult to identify because the difference in the concentrations before and after the jump might be just few µg·m-3 ("possible jump") or because the jump is sustained over the whole monitoring period and only detectable if PM concentrations are simultaneously measured by other instruments ("hidden jump"). Moreover, in areas of relatively low PM levels, the unit reported concentration of 0µg·m-3 for ambient PM concentration or even negative concentration values which may seriously compromise the dataset. These data suggest issues with the detection of low PM concentrations, which could be due to an incorrect instrument offset or the factory calibration setting being inadequate for these PM concentrations. The upward and downward artefact jumps were not related to especially dusty or clean conditions, since they have been observed in many kinds of environments: indoor and outdoor school environments, subway stations and in ambient urban background air. Therefore, PM concentration data obtained with the TSI DustTrak DRX models should be handled with care and meticulously revised before being considered valid. To prevent these issues the use of auto zero module is recommended, so the DustTrak monitor is automatic re-zeroed without requiring the presence of any user.

Polybrominated diphenyl ethers (PBDEs) in dust from primary schools in South East Queensland, Australia.

PBDE concentrations are higher in children compared to adults with exposure suggested to include dust ingestion. Besides the home environment, children spend a great deal of time in school classrooms which may be a source of exposure. As part of the "Ultrafine Particles from Traffic Emissions and Children's Health (UPTECH)" project, dust samples (n=28) were obtained in 2011/12 from 10 Brisbane, Australia metropolitan schools and analysed using GC and LC-MS for polybrominated diphenyl ethers (PBDEs) -17, -28, -47, -49, -66, -85, -99, -100, -154, -183, and -209. Σ11PBDEs ranged from 11-2163 ng/g dust; with a mean and median of 600 and 469 ng/g dust, respectively. BDE-209 (range n.d. -2034 ng/g dust; mean (median) 402 (217)ng/g dust) was the dominant congener in most classrooms. Frequencies of detection were 96%, 96%, 39% and 93% for BDE-47, -99, -100 and -209, respectively. No seasonal variations were apparent and from each of the two schools where XRF measurements were carried out, only two classroom items had detectable bromine. PBDE intake for 8-11 year olds can be estimated at 0.094 ng/day BDE-47; 0.187 ng/day BDE-99 and 0.522ng/day BDE-209 as a result of ingestion of classroom dust, based on mean PBDE concentrations. The 97.5% percentile intake is estimated to be 0.62, 1.03 and 2.14 ng/day for BDEs-47, -99 and -209, respectively. These PBDE concentrations in dust from classrooms, which are higher than in Australian homes, may explain some of the higher body burden of PBDEs in children compared to adults when taking into consideration age-dependant behaviours which increase dust ingestion.

Ultrafine Particles from Traffic Emissions and Children's Health (UPTECH) in Brisbane, Queensland (Australia): study design and implementation.

Ultrafine particles are particles that are less than 0.1 micrometres (µm) in diameter. Due to their very small size they can penetrate deep into the lungs, and potentially cause more damage than larger particles. The Ultrafine Particles from Traffic Emissions and Children's Health (UPTECH) study is the first Australian epidemiological study to assess the health effects of ultrafine particles on children's health in general and peripheral airways in particular. The study is being conducted in Brisbane, Australia. Continuous indoor and outdoor air pollution monitoring was conducted within each of the twenty five participating school campuses to measure particulate matter, including in the ultrafine size range, and gases. Respiratory health effects were evaluated by conducting the following tests on participating children at each school: spirometry, forced oscillation technique (FOT) and multiple breath nitrogen washout test (MBNW) (to assess airway function), fraction of exhaled nitric oxide (FeNO, to assess airway inflammation), blood cotinine levels (to assess exposure to second-hand tobacco smoke), and serum C-reactive protein (CRP) levels (to measure systemic inflammation). A pilot study was conducted prior to commencing the main study to assess the feasibility and reliably of measurement of some of the clinical tests that have been proposed for the main study. Air pollutant exposure measurements were not included in the pilot study.