Levels Of Population Coverage Research Articles

The influence of health insurance on coverage of a country’s population with medical services

One of the effective ways to increase the level of population coverage with medical services is health insurance. The paper aims to determine what type of health insurance (compulsory, social, or voluntary) has the greatest impact on a country’s ability to provide large-scale and timely medical services to citizens, as measured by the number of unmet needs for medical examination, treatable and preventable mortality. The control variables included a country’s population size, the level of economic well-being, and the scale of the public health system (number of doctors and hospital beds) based on EUROSTAT data for all 27 EU countries in 2012–2021. Modelling (regression models of panel data with fixed and random effects in STATA 18, Wald test, Hausman test, Breusch and Pagan test) proved that only one of three researched types of insurance – voluntary health insurance – positively influences a country’s ability to provide large-scale and timely medical services to citizens: an increase in its volume by 1% leads to a decrease in unmet needs in medical examination on average across all EU countries by 0.26%, treatable mortality rate by 0.08%, preventive mortality rate by 0.27%. The influence of the other two types – compulsory and social – was not confirmed (received regression coefficients for these variables are not statistically significant). This emphasizes the importance of citizens’ conscious attitude to their health (due to the increase in voluntary health insurance) both in strengthening public health and in ensuring faster and better access to medical services.

FINANCIAL LEVERAGES OF THE REGULATION OF RESIDENTIAL CONSTRUCTION

The increasing level of population coverage with housing has traditionally been among the most relevant and challenging issues for the national economy of Ukraine. The military conflict, now in its second year, is changing the priorities of the public housing policy and requiring the search for new efficient methods of restoring the lost housing stock and regulating housing construction. The article addresses the volume of capital investment in residential construction in Ukraine and explains the financial framework for residential construction regulation. World best practices in the use of financial instruments in the regulation of the industry are systematized. The authors' view of the system of financial leverage of residential construction regulation is offered. The analysis of the housing affordability indicators shows that the average household income is insufficient to purchase housing and repay a mortgage. Meanwhile, the research indicates that a mortgage is one of the most common financial instruments for the purchase of housing for Ukrainians. The analysis of the level and dynamics of mortgage interest rates shows that they are 4.6 times higher in the euro than in the EU countries. The study of modern housing practices in Ukraine emphasizes the need to introduce new principles of sustainable financial regulation in residential construction. The article substantiates a set of these principles and recommends their implementation. The assessment of modern realities and consequences of hostilities in Ukraine reveals significant losses of housing stock (about 40%) and the need to change the priorities and tasks of public housing policy. An examination of the country's recovery and post-war housing programs allows the identification of the principles of transparency, openness, inclusivity, energy efficiency, resource efficiency, and sustainability as key strategic priorities in financial regulation.

Evaluation of Clinical and Economic Efficiency and Impact of Mass Fluorography Screening on Tuberculosis Epidemiological Rates in Four Federal Districts of the Russian Federation with Different Levels of Population Coverage with Mass Fluorography Screening

The objective: analysis of clinical cases of tuberculous spondylitis in HIV-infected patients with the detection of HIV RNA in the focus of vertebral bodies destruction.Subjects and Methods. Medical records of 2 HIV-infected patients who underwent surgery for verified tuberculous spondylitis were analyzed. Parts of the vertebral bodies collected during surgery were examined (PCR, microbiological and histological tests), those were parts with destruction and fragments of healthy iliac bone necessary to fill the implant during corporodesis.Results. RNA HIV was detected in the foci of bone destructionas as well as M. tuberculosis DNA. The viral load in the fragments of healthy iliac bone and peripheral blood of these patients was undetectable.

A step towards harmonising human biomonitoring study setup on European level: Materials provided and lessons learnt in HBM4EU.

Internal exposure of the human body to potentially harmful chemical substances can be assessed by Human Biomonitoring (HBM). HBM can be used to generate conclusive data that may provide an overview of exposure levels in entire or specific population groups. This knowledge can promote the understanding of potential risks of the substances of interest or help monitoring the success of regulatory measures taken on the political level. Study planning and design are key elements of any epidemiologic study to generate reliable data. In the field of HBM, this has been done using differing approaches on various levels of population coverage so far. Comparison and combined usage of the resulting data would contribute to understanding exposure and its factors on a larger scale, however, the differences between studies make this a challenging and somewhat limited endeavour. This article presents templates for documents that are required to set up an HBM study, thus facilitating the generation of harmonised HBM data as a step towards standardisation of HBM in Europe. They are designed to be modular and adaptable to the specific needs of a single study while emphasising minimum requirements to ensure comparability. It further elaborates on the challenges encountered during the process of creating these documents during the runtime of the European Joint Programme HBM4EU in a multi-national expert team and draws up lessons learnt in the context of knowledge management.

Evaluation of Clinical and Economic Efficiency and Impact of Mass Fluorography Screening on Tuberculosis Epidemiological Rates in Four Federal Districts of the Russian Federation with Different Levels of Population Coverage with Mass Fluorography Screening

The objective: to evaluate the clinical and economic efficiency and impact of mass fluorography screening of the population on tuberculosis mortality and rates of timely tuberculosis detection in four federal districts of the Russian Federation with different levels of tuberculosis detection and coverage of the population with fluorography mass screening.Subjects and Methods. Analytical materials of the Federal Center for Monitoring of Tuberculosis Transmission Control in the Russian Federation posted on official websites were used. The rates were analyzed by applied statistics methods. All statistical calculations were performed with 0.95 significance.Results. A correlation analysis was performed between the coverage, effectiveness of tuberculosis detection by mass fluorography screening of the population and main rates reflecting the epidemic situation and timeliness of tuberculosis detection in the Russian Federation and its four federal districts. There was no correlation between the detection effectiveness and main markers of timeliness of tuberculosis detection. It was found out that against the background of increased costs for mass fluorography screening, its implementation did not provide significant positive results in reducing tuberculosis incidence and mortality which indicated their low clinical and economic efficiency.

Pattern of population coverage of a social health insurance scheme in a Southwest Nigeria State: A 3-year post implementation evaluation

Aims: Social health insurance scheme is capable of minimizing inequity of access to health services, and thereby enhance an improvement in population health outcomes. Recently the National Health Insurance Scheme (NHIS) of Nigeria decentralized its management to the sub-national levels, thus the emergence of State Health Insurance Schemes (SHIS). The SHIS of Oyo State Nigeria started operations about three years ago (June 2017). There is limited/sparse evidence on the performance of the scheme since its inception. Therefore, the aim of this study was to assess the scheme’s level of population coverage in the first three years of implementation. The findings will also provide an evidence base to inform the repositioning of the scheme for improved performance and enable it achieve the purpose of its establishment. Methods: Service data from the server of Oyo SHIS were downloaded, collated and analyzed with excel software. Data extraction, cleaning and analysis covered a period of three months (September – October, 2020). Descriptive statistics were used to summarise the data. Population coverage distributions were expressed as frequency and percentages. Frequency tables and graphs were generated to disaggregate the findings. Conclusion: Stakeholders in the Oyo State SHIS need to re-strategize to reposition the scheme for an accelerated population coverage as a proxy for performance assessment. Acknowledgements: Authors wish to acknowledge Oyo State Health Insurance Agency for the permission to make use of the data and to submit the manuscript for publication. We authors would like to sincerely acknowledge the contributions of Prof. Charles Wiysonge and that of Dr. Chukwudi Nnaji for the comprehensive review and suggestions made on this manuscript. Many thanks. Authors' contributions: David Adewole conceived and designed the study. Wuraola Ladepo and Temitope Ilori did data collection and analysis. Adewole, Owolabi and Akande contributed equally to the manuscript write up. All authors read through the manuscript draft the second time. All authors agreed to the final manuscript. Conflict of interests: None declared.

Analysis and Outlook for the Development of Measles Epidemic Situation during the COVID-19 Pandemic

Relevance. The success of the global community in the fight against measles through vaccination at the beginning of the twentyfirst century allowed WHO to declare the goal of eliminating this infection by 2010. However, ten years later, the problem of the growing incidence of measles has become relevant again for all countries of the world. The pandemic of the new coronavirus infection (COVID-19) has affected all spheres of human life and has exacerbated the situation in the fight against other infections, including those managed with the help of specific prophylaxis. Since the measles contagiosity index and mortality rate are significantly higher than similar characteristics of COVID-19, the risk of increasing the incidence of this infection in the coming years is difficult to overestimate.Aim of the study: to assess the epidemic situation of measles in the context of the COVID-19 pandemic, as well as the prospects for its development; to propose preventive measures.Materials and methods. The article analyzes the statistical materials available on the official websites of the WHO (WHO). https://www.who.int/data/), the CDC US (https://www. cdc.gov) and the Federal Service of Rospotrebnadzor (https://www.rospotrebnadzor.ru/) on vaccination coverage and measles incidence in 13 countries in the WHO European Region and the United States. The epidemic situation on measles, as well as the level of population coverage with vaccination against its pathogen in the Russian Federation, were assessed according to the Federal State Statistical Observation forms 2010 – 2020: Form 2 «Information on infectious and parasitic diseases» and Form 6 «Information on the populations of children and adults vaccinated against infectious diseases».Results. It has been established that the increase in the measles incidence occurred in 2017–2019 worldwide, including European countries with a population coverage of two vaccine doses at the 97% level between 2010 and 2019. The prevalence of measles cases in children under the age of 10 is shown, as well as the wide range (from 56.9% to 10.9%) in the proportion of vaccinated persons among them. The results obtained indicate the existence of problems in the organization of modern vaccine prevention. The introduction of widespread restrictive and quarantine measures against the COVID-19 pandemic, on the one hand, has reduced the incidence of measles and, on the other hand, has exacerbated the difficulties in implementing measles prevention. Thus, the results indicate a possible increase in measles incidence in the population after the end of the COVID-19 pandemic.Conclusion. It is necessary to immediately develop an action plan to catch up on the coverage and increase the rate of routine vaccination, to improve the statistical record of persons subject to the introduction of the vaccine and vaccinated, as well as to overcome anti-vaccination attitude among the population.

Advances in mapping population and demographic characteristics at small-area levels.

Temporally and spatially highly resolved information on population characteristics, including demographic profile (e.g. age and sex), ethnicity and socio-economic status (e.g. income, occupation, education), are essential for observational health studies at the small-area level. Time-relevant population data are critical as denominators for health statistics, analytics and epidemiology, to calculate rates or risks of disease. Demographic and socio-economic characteristics are key determinants of health and important confounders in the relationship between environmental contaminants and health.In many countries, census data have long been the source of small-area population denominators and confounder information. A strength of the traditional census model has been its careful design and high level of population coverage, allowing high-quality detailed data to be released for small areas periodically, e.g. every 10 years. The timeliness of data, however, becomes a challenge when temporally and spatially highly accurate annual (or even more frequent) data at high spatial resolution are needed, for example, for health surveillance and epidemiological studies. Additionally, the approach to collecting demographic population information is changing in the era of open and big data and may eventually evolve to using combinations of administrative and other data, supplemented by surveys.We discuss different approaches to address these challenges including (i) the US American Community Survey, a rolling sample of the US population census, (ii) the use of spatial analysis techniques to compile temporally and spatially high-resolution demographic data and (iii) the use of administrative and big data sources as proxies for demographic characteristics.

Logistics of carpet recycling in the U.S.: designing the collection network

Efficient collection of post-consumer carpet is an important part of the carpet recycling process that helps to reduce the cost of recycled materials as well as provide sufficient volumes of carpet for recycling facilities. This paper focuses on the design of a collection network for carpet in the U.S. The location set covering optimization model formulated in the paper allows locating the minimum number of collection centers throughout the U.S. to reach a specific level of population coverage and as a result, a target collection rate. To solve real-scale instances of the problem, a novel randomized greedy heuristic is developed. The heuristic is shown to perform better than existing greedy heuristics in the literature. In addition, the paper presents the resulting nationwide carpet collection networks for different levels of population coverage. The results of the study can be used for U.S. carpet recycling policy-making decisions.

Population characteristics and geographic coverage of primary care facilities

BackgroundThe location of General Practitioner (GP) facilities is an important aspect in the design of healthcare systems to ensure they are accessible by populations with healthcare needs. A key consideration in the facility location decision involves matching the population need for the services with the supply of healthcare resources. The literature points to several factors which may be important in the decision making process, such as deprivation, transportation, rurality, and population age.MethodsThis study uses two approaches to examine the factors associated with GP accessibility in Northern Ireland. The first uses multinomial regression to examine the factors associated with GP coverage, measured as the proportion of people who live within 1.5 km road network distance from the nearest GP practice. The second focuses on the factors associated with the average travel distance to the nearest GP practice, again measured using network distance. The empirical research is carried out using population and geospatial data from Northern Ireland, across 890 Super Output Areas and 343 GP practices.ResultsIn 19% of Super Output Areas, all of the population live within 1.5 km of a GP practice, whilst in 24% none of the population live within 1.5 km. The regression results show that there are higher levels of population coverage in more deprived areas, smaller areas, and areas that have more elderly populations. Similarly, the average travel distance is related to deprivation, population age, and area size.ConclusionsThe results indicate that GP practices are located in areas with higher levels of service need, but also that care needs to be taken to ensure rural populations have sufficient access to services, whether delivered through GP practices or through alternative services where GP practices are less accessible. The methodology and results should be considered by policy makers and healthcare managers when making decisions about GP facility location and service provision.

Bangladesh policy on prevention and control of non-communicable diseases: a policy analysis

BackgroundThis paper is aimed at critically assessing the extent to which Non-Communicable Disease NCD-related policies introduced in Bangladesh align with the World Health Organization’s (WHO) 2013–2020 Action Plan for the Global Strategy for the Prevention and Control of NCDs.MethodsThe authors reviewed all relevant policy documents introduced by the Government of Bangladesh since its independence in 1971. The literature review targeted scientific and grey literature documents involving internet-based search, and expert consultation and snowballing to identify relevant policy documents. Information was extracted from the documents using a specific matrix, mapping each document against the six objectives of the WHO 2013–2020 Action Plan for the Global Strategy for the Prevention and Control of NCDs.ResultsA total of 51 documents were identified. Seven (14%) were research and/or surveys, nine were on established policies (17%), while seventeen (33%) were on action programmes. Five (10%) were related to guidelines and thirteen (25%) were strategic planning documents from government and non-government agencies/institutes. The study covered documents produced by the Government of Bangladesh as well as those by quasi-government and non-government organizations irrespective of the extent to which the intended policies were implemented.ConclusionsThe policy analysis findings suggest that although the government has initiated many NCD-related policies or programs, they lacked proper planning, implementation and monitoring. Consequently, Bangladesh over the years had little success in effectively addressing the growing burden of non-communicable diseases. It is imperative that future research critically assess the effectiveness of national NCD policies by monitoring their implementation and level of population coverage.

Community engagement and the social context of targeted malaria treatment: a qualitative study in Kayin (Karen) State, Myanmar

BackgroundThe spread of artemisinin-resistance in Plasmodium falciparum is a threat to current global malaria control initiatives. Targeted malaria treatment (TMT), which combines mass anti-malarial administration with conventional malaria prevention and control measures, has been proposed as a strategy to tackle this problem. The effectiveness of TMT depends on high levels of population coverage and is influenced by accompanying community engagement activities and the local social context. The article explores how these factors influenced attitudes and behaviours towards TMT in Kayin (Karen) State, Myanmar.MethodsSemi-structured interviews were conducted with villagers from study villages (N = 31) and TMT project staff (N = 14) between March and July 2015.ResultsCommunity engagement consisted of a range of activities to communicate the local malaria situation (including anti-malarial drug resistance and asymptomatic malaria), the aims of the TMT project, and its potential benefits. Community engagement was seen by staff as integral to the TMT project as a whole and not a sub-set of activities. Attitudes towards TMT (including towards community engagement) showed that developing trusting relationships helped foster participation. After initial wariness, staff received hospitality and acceptance among villagers. Offering healthcare alongside TMT proved mutually beneficial for the study and villagers. A handful of more socially-mobile and wealthy community members were reluctant to participate. The challenges of community engagement included time constraints and the isolation of the community with its limited infrastructure and a history of conflict.ConclusionsCommunity engagement had to be responsive to the local community even though staff faced time constraints. Understanding the social context of engagement helped TMT to foster respectful and trusting relationships. The complex relationship between the local context and community engagement complicated evaluation of the community strategy. Nonetheless, the project did record high levels of population coverage.

Effectiveness of a triple-drug regimen for global elimination of lymphatic filariasis: a modelling study

Lymphatic filariasis is targeted for elimination as a public health problem by 2020. The principal approach used by current programmes is annual mass drug administration with two pairs of drugs with a good safety profile. However, one dose of a triple-drug regimen (ivermectin, diethylcarbamazine, and albendazole) has been shown to clear the transmissible stage of the helminth completely in treated individuals. The aim of this study was to use modelling to assess the potential value of mass drug administration with the triple-drug regimen for accelerating elimination of lymphatic filariasis in different epidemiological settings. We used three different transmission models to compare the number of rounds of mass drug administration needed to achieve a prevalence of microfilaraemia less than 1% with the triple-drug regimen and with current two-drug regimens. In settings with a low baseline prevalence of lymphatic filariasis (5%), the triple-drug regimen reduced the number of rounds of mass drug administration needed to reach the target prevalence by one or two rounds, compared with the two-drug regimen. For areas with higher baseline prevalence (10-40%), the triple-drug regimen strikingly reduced the number of rounds of mass drug administration needed, by about four or five, but only at moderate-to-high levels of population coverage (>65%) and if systematic non-adherence to mass drug administration was low. Simulation modelling suggests that the triple-drug regimen has potential to accelerate the elimination of lymphatic filariasis if high population coverage of mass drug administration can be achieved and if systematic non-adherence with mass drug administration is low. Future work will reassess these estimates in light of more clinical trial data and to understand the effect on an individual country's programme. Bill & Melinda Gates Foundation.

What Is Needed to Eradicate Lymphatic Filariasis? A Model-Based Assessment on the Impact of Scaling Up Mass Drug Administration Programs.

BackgroundLymphatic filariasis (LF) is a neglected tropical disease for which more than a billion people in 73 countries are thought to be at-risk. At a global level, the efforts against LF are designed as an elimination program. However, current efforts appear to aim for elimination in some but not all endemic areas. With the 2020 goal of elimination looming, we set out to develop plausible scale-up scenarios to reach global elimination and eradication. We predict the duration of mass drug administration (MDA) necessary to reach local elimination for a variety of transmission archetypes using an existing model of LF transmission, estimate the number of treatments required for each scenario, and consider implications of rapid scale-up.MethodologyWe have defined four scenarios that differ in their geographic coverage and rate of scale-up. For each scenario, country-specific simulations and calculations were performed that took into account the pre-intervention transmission intensity, the different vector genera, drug regimen, achieved level of population coverage, previous progress toward elimination, and potential programmatic delays due to mapping, operations, and administration.Principal FindingsOur results indicate that eliminating LF by 2020 is unlikely. If MDA programs are drastically scaled up and expanded, the final round of MDA for LF eradication could be delivered in 2028 after 4,159 million treatments. However, if the current rate of scale-up is maintained, the final round of MDA to eradicate LF may not occur until 2050.Conclusions/SignificanceRapid scale-up of MDA will decrease the amount of time and treatments required to reach LF eradication. It may also propel the program towards success, as the risk of failure is likely to increase with extended program duration.

Effectiveness of a combination prevention strategy for HIV risk reduction with men who have sex with men in Central America: a mid-term evaluation

BackgroundDespite over a decade of research and programming, little evidence is available on effective strategies to reduce HIV risks among Central American men who have sex with men (MSM). The Pan-American Social Marketing Organization (PASMO) and partners are implementing a HIV Combination Prevention Program to provide key populations with an essential package of prevention interventions and services: 1) behavioral, including interpersonal communications, and online outreach; 2) biomedical services including HIV testing and counseling and screening for STIs; and 3) complementary support, including legal support and treatment for substance abuse. Two years into implementation, we evaluated this program’s effectiveness for MSM by testing whether exposure to any or a combination of program components could reduce HIV risks.MethodsPASMO surveyed MSM in 10 cities across Guatemala, El Salvador, Nicaragua, Costa Rica, and Panama in 2012 using respondent-driven sampling. We used coarsened exact matching to create statistically equivalent groups of men exposed and non-exposed to the program, matching on education, measures of social interaction, and exposure to other HIV prevention programs. We estimated average treatment effects of each component and all combined to assess HIV testing and condom use outcomes, using multivariable logistic regression. We also linked survey data to routine service data to assess program coverage.ResultsExposure to any program component was 32% in the study area (n = 3531). Only 2.8% of men received all components. Men exposed to both behavioral and biomedical components were more likely to use condoms and lubricant at last sex (AOR 3.05, 95% CI 1.08, 8.64), and those exposed to behavioral interventions were more likely to have tested for HIV in the past year (AOR 1.76, 95% CI 1.01, 3.10).ConclusionsPASMO’s strategies to reach MSM with HIV prevention programming are still achieving low levels of population coverage, and few men are receiving the complete essential package. However, those reached are able to practice HIV prevention. Combination prevention is a promising approach in Central America, requiring expansion in coverage and intensity.

Advancing the application of systems thinking in health: understanding the growing complexity governing immunization services in Kerala, India.

BackgroundGoverning immunization services in a way that achieves and maintains desired population coverage levels is complex as it involves interactions of multiple actors and contexts. In one of the Indian states, Kerala, after routine immunization had reached high coverage in the late 1990s, it started to decline in some of the districts. This paper describes an application of complex adaptive systems theory and methods to understand and explain the phenomena underlying unexpected changes in vaccination coverage.MethodsWe used qualitative methods to explore the factors underlying changes in vaccination coverage in two districts in Kerala, one with high and one with low coverage. Content analysis was guided by features inherent to complex adaptive systems such as phase transitions, feedback, path dependence, and self-organization. Causal loop diagrams were developed to depict the interactions among actors and critical events that influenced the changes in vaccination coverage.ResultsWe identified various complex adaptive system phenomena that influenced the change in vaccination coverage levels in the two districts. Phase transition describes how initial acceptability to vaccination is replaced by a resistance in northern Kerala, which involved new actors; actors attempting to regain acceptability and others who countered it created several feedback loops. We also describe how the authorities have responded to declining immunization coverage and its impact on vaccine acceptability in the context of certain highly connected actors playing disproportionate influence over household vaccination decisions.Theoretical exposition of our findings reveals the important role of trust in health workers and institutions that shape the interactions of actors leading to complex adaptive system phenomena.ConclusionsAs illustrated in this study, a complex adaptive system lens helps to uncover the ‘real’ drivers for change. This approach assists researchers and decision makers to systematically explore the driving forces and factors in each setting and develop appropriate and timely strategies to address them. The study calls for greater consideration of dynamics of vaccine acceptability while formulating immunization policies and program strategies. The analytical approaches adopted in this study are not only applicable to immunization or Kerala but to all complex interventions, health systems problems, and contexts.

MHealth Series: Measuring maternal newborn and child health coverage by text messaging – a county–level model for China

BackgroundEffective interventions in maternal, newborn and child health (MNCH), if achieving high level of population coverage, could prevent most of deaths in children under five years of age. High–quality measurements of MNCH coverage are essential for tracking progress and making evidence–based decisions.MethodsMNCH coverage data are mainly collected through fieldworkers’ interview with preselected households in standard programs of Demographic and Health Surveys (DHS) or Multiple Indicator Cluster Surveys (MICS) in most low– and middle–income countries. Household surveys will continue to be the major data source for MNCH coverage in the foreseeable future. However, face–to–face data collection broadly used in household surveys is labor–intensive, time–consuming and expensive. Mobile phones are drawing more and more interest in medical research with the rapid increase in usage and text messaging could be an innovative way of data collection, that is, we could collect DHS data through mHealth method. We refer to it as “mDHS”.FindingWe propose in this paper a conceptual model for measuring MNCH coverage by text messaging in China. In developing this model, we considered resource constraints, sample representativeness, sample size and survey bias. The components of the model are text messaging platform, routine health information system, health facilities, communities and households.ConclusionsMeasuring MNCH interventions coverage by text messaging could be advantageous in many ways and establish a much larger evidence–base for MNCH health policies in China. Before mDHS could indeed be launched, research priorities would include a systematic assessment of routine health information systems and exploring feasibility to collect name lists, mobile phone numbers and general demographic and socio–economic data; qualitative interviews with health workers and caregivers; assessment of data validity of all indicators to be collected by text messaging; and exploring approaches to increase participation rate.

The need for scaling up research on effective strategies for delivering child-survival interventions

Considerations as to the feasibility with which child survival interventions can be delivered at high levels of population coverage, have been described as a central criterion of interventions intended to reduce child mortality...

Optimising bait-station delivery of population-control agents to brushtail possums: field test of spatial model predictions

Context Low-volume control agents based on new biotechnologies are likely to be point-delivered to wildlife populations using devices such as bait stations. However, data and theory to underpin the development of strategies for such a use of bait stations are lacking. Aims In a large-scale replicated field trial of brushtail possum (Trichosurus vulpecula) populations, we estimated the levels of coverage achieved with bait-station grids at three densities (0.2, 0.6 and 1.0 ha–1), with and without pre-feeding, to test the predictions of an existing model of bait-station delivery based on relationships derived from leghold trapping. Methods We first marked possums using conventional capture–mark–recapture techniques, and then estimated population coverage by recovering animals poisoned by encapsulated cyanide delivered by the bait stations. Key results The two key model predictions, that 90% population coverage could be achieved at 0.6 bait stations per hectare and that pre-feeding was not required to achieve this level, were not upheld by the field trials. Instead, there was a poor fit between model predictions and observed levels of population coverage. An investigation of key model assumptions demonstrated issues with both model structure and parameterisation. Conclusions Neither previously documented relationships for possum interactions with leghold traps, nor correlations between possum interaction rates with such devices and bait stations, are generically applicable across all populations. Implications While the existing model of bait-station delivery to possums fits the data for some field operations and trials, it is not applicable to all populations. Incorporating habitat and seasonal effects on possum home-range behaviour could potentially improve model prediction. Our results also have implications for the accuracy of index-based methods of possum population monitoring that use leghold traps, such as the Residual Trap Catch Index.

The potential impact of an HIV vaccine with rapidly waning protection on the epidemic in Southern Africa: Examining the RV144 trial results

Background The prime-boost HIV vaccine regimen used in the recent RV144 trial resulted in modest efficacy of 31% over 3.5 years, but was substantially higher in the first year post-vaccination. We sought to explore the potential impact of a vaccine with rapidly waning efficacy in a South African population. Methods We explored two strategies using a dynamic compartmental epidemic model for heterosexual transmission of HIV: [1] vaccination of a single cohort (30%, 60% or 90% of the initial population), with exponentially waning efficacy, but booster vaccinations at 5- or 2-year intervals, and [2] continuous vaccination of the unvaccinated population at the same coverage levels (30%, 60% or 90%) but with a constant efficacy vaccine of short duration. We also examined potential changes in post-vaccination condom use. Results The single cohort vaccination strategies did not have a substantial impact on HIV prevalence, although without boosters they still prevented 2–6% of the expected infections at 20 years, depending on the population coverage. The 5-year and 2-year booster strategies prevented 8–24% and 17–45% of the expected infections, respectively. Continuous vaccination to maintain population coverage levels resulted in more substantial reductions in population HIV prevalence and greater numbers of infections prevented: HIV prevalence at 20 years was reduced from 23% to 8–14% and the number of expected infections was decreased by 34–59%, depending on the population coverage level. Moderate changes in post-vaccination condom use did not substantially affect these outcomes. Conclusions An HIV vaccine with partial efficacy and declining protection similar to the RV144 vaccine could prevent a substantial proportion of HIV infections if booster vaccinations were effective and available. Our estimates of the population impact of vaccination would be improved by further understanding of the duration of protection, the effectiveness of booster vaccination, and whether the vaccine efficacy varies between subpopulations at higher and lower risk of exposure.