Health inequalities at the intersection of multiple social determinants among under five children residing Nairobi urban slums: An application of multilevel analysis of individual heterogeneity and discriminatory accuracy (MAIHDA).

In this analysis we examine through an intersectionality lens how key social determinants of health (SDOH) are associated with health conditions among under-five children (<5y) residing in Nairobi slums, Kenya. We used cross-sectional data collected from Nairobi slums between June and November 2012 to explore how multiple interactions of SDoH shape health inequalities in slums. We applied multilevel analysis of individual heterogeneity and discriminatory accuracy (MAIHDA) approach. We constructed intersectional strata for each health condition from combinations of significant SDoH obtained using univariate analyses. We then estimated the intersectional effects of health condition in a series of MAIHDA logistic regression models distinguishing between additive and interaction effects. We quantified discriminatory accuracy (DA) of the intersectional strata by means of the variance partitioning coefficient (VPC) and the area under the receiver operating characteristic curve (AUC-ROC). The total participants were 2,199 <5y, with 120 records (5.5%) dropped because health conditions were recorded as "not applicable". The main outcome variables were three health conditions: 1) whether a child had diarrhea or not, 2) whether a child had fever or not, and 3) whether a child had cough or not in the previous two weeks. We found non-significant intersectional effects for each health condition. The head of household ethnic group was significantly associated with each health condition. We found good DA for diarrhea (VPC = 9.0%, AUC-ROC = 76.6%) an indication of large intersectional effects. However, fever (VPC = 1.9%, AUC-ROC = 66.3%) and cough (VPC = 0.5%, AUC-ROC = 61.8%) had weak DA indicating existence of small intersectional effects. Our study shows pathways for SDoH that affect diarrhea, cough, and fever for <5y living in slums are multiplicative and shared. The findings show that <5y from Luo and Luhya ethnic groups, recent migrants (less than 2 years), and households experiencing CHE are more likely to face worse health outcomes. We recommend relevant stakeholders to develop strategies aimed at identifying these groups for targeted proportionate universalism based on the level of their need.

Voices and challenges of marginalized and vulnerable groups in urban informal settlements in Nairobi, Kenya: building on a spectrum of community-based participatory research approaches.

Urbanization is rapidly increasing across Africa, including in Nairobi, Kenya. Many people, recent migrants and long-term residents, live within dense and dynamic urban informal settlements. These contexts are fluid and heterogeneous, and deepening the understanding of how vulnerabilities and marginalization are experienced is important to inform pointed action, service delivery and policy priorities. The aim of this paper is to explore vulnerabilities and marginalization within Korogocho and Viwandani informal settlements in Nairobi and generate lessons on the value of a spectrum of community based participatory research approaches for understanding health and well-being needs and pinpointing appropriate interventions. In the exploratory stages of our ARISE consortium research, we worked with co-researchers to use the following methods: social mapping, governance diaries, and photo voice. Social mapping (including the use of Focus Group Discussions) identified key vulnerable groups: marginalized and precarious child heads of households (CHHs), Persons with disability who face multiple discrimination and health challenges, and often isolated older adults; and their priority needs, including health, education, water and sanitation. The governance diaries generated an understanding of the perceptions of the particularly vulnerable and marginalized informal settlement residents regarding the various people and institutions with the power to influence health and wellbeing; while photo voice highlighted the lived experiences of vulnerability and marginality. Understanding and responding to fluid and intersecting marginalities and vulnerabilities within growing urban informal settlements is particularly critical to achieving inclusive urbanization, where no one is left behind, a theme central to the Sustainable Development Goals and Kenya's Vision 2030.

Social inclusion of persons with disability in employment: what would it take to socially support employed persons with disability in the labor market?

Introduction: One of the major challenges that persons with disabilities (PWDs) are facing globally is unemployment. The challenge is attributed to systems that are not built with inclusivity in mind by employers. As such, the work of inclusion is not inviting PWDs to do more but to make a difference through social support. Most research on inclusion in the employment of PWDs in low-income settings has been concentrated upon the labor "supply" side, and to the best of our knowledge, no specific studies moved toward inclusion in employment issues from the employers' perspective in informal settlements. Notably, our research question is: "what would it take to socially support employed PWD in informal settlements building from the perspectives of employers." Methods: This paper used data from in-depth interviews with 38 service providers in the education, health, water, sanitation, and solid waste management sectors and two sub-county officials in two informal settlements in Nairobi, Kenya. The service providers were employers or entrepreneurs who had hired PWDs in their workspaces and the sub-county officials that had vast experiences with employed PWDs. Data from transcripts were analyzed by the research team using content analysis. Results: The social support offered to employed PWDs included listening to them with a concern; identifying their strengths and obstacles; planning for them based on their qualities, knowledge, and experience and linking them with existing opportunities; creating specific opportunities and facilitating their access to opportunities; gradual withdrawal of support by support group; and, lastly, compromise by employers with PWD inclusion strategies. Study participants described how misdirected and inadequate resources, dissatisfaction and unhappiness, and conflicts at the workplace associated with non-inclusion were constraints to social support. Employment matters affecting PWDs are complex and require multi-pronged context-specific social support approaches. Essential to the functioning of an inclusive workplace for PWDs were communication, coordination, sharing of the workload, and supporting individual PWD. Conclusion: Inclusion of PWDs in the labor market is about generating a supportive workplace where people are valued and appreciated without judgement for what they can contribute. Notably, in the absence of jobs for everyone and high unemployment rates among every segment of the population, there is a need for an awareness creation, mobilization, and sensitization of employers and investors around the competencies of PWDs and their need to socially support on an impartial basis. On the other hand, employment centers could establish stations in low-income areas to advise and support PWDs on career opportunities that are disability-friendly and partner with employers to avail information about the capabilities of PWDs. Conversely, the government should provide some tax-related benefits to employers to upsurge employer incentives for hiring PWDs and empower employers on benefits and positive culture of employing PWDs. At all times, employers should be hands-on and involve diverse stakeholders to implement current policies and frameworks in different work contexts across the country and beyond.

Mapping social accountability actors and networks and their roles in water, sanitation and hygiene (WASH) in childcare centres within Nairobi's informal settlements: A governance diaries approach.

INTRODUCTION: Despite many institutions gaining access to improved water sanitation and hygiene (WASH) services, childcare centres in informal settlements have low access and poor condition of WASH services. It is imperative to understand how existing actors and social networks operate in the WASH sector in childcare centres in Nairobi's informal settlements. OBJECTIVE: To empirically map and understand how different actors within informal settlements influence the provision of adequate and quality water, sanitation and hygiene services within childcare centres in Nairobi's informal settlements. METHODS: This was a qualitative study. We conducted an ethnographic study using governance diaries with 24 participants from Korogocho and Viwandani informal settlements in Nairobi, Kenya. The governance diaries approach involved conducting bi-weekly governance in-depth interviews (IDIs) with study participants for 4 months, complemented with observations, reflections, participant diaries and informal discussions. We used a framework analysis which is partly deductive, informed by the governance framework and stakeholder framework. RESULTS: Social accountability actors were individuals or groups involved in WASH service provision in childcare centres. The actors included both key actors (actors who are primary to meeting the day-to-day WASH service needs of children) and non-key actors (actors operating in the WASH sector but not always present for day-to-day provision in childcare centres). The key actors were unanimously identified as childcare centre owners/teachers and parents/guardians as they had a more direct role in the provision of WASH services in childcare centres. The actors had direct, possible or desired networks, with the direct networks portrayed more by the parents and childcare centre owners, whose roles included acting as a voice and responding to the WASH service needs of children as it relates to access and quality. Centre owners had more power/authority over WASH services for children in childcare centres than the parents. Key actors derived power by their discretion depending on whether a decision was beneficial to children or not. Lastly, the interest of key actors were diverse ranging from income generation, access to WASH services by children, compliance with government regulations, and promotion of child health, to the prevention of the spread of diseases. CONCLUSION: Our study highlights that parents and childcare owners play an important role in WASH service provision. While service providers and other players may be statutorily given primary responsibilities for WASH provision, and more visible in official standing, among study participants they are not seen as primary actors but secondary players with ancillary responsibilities. We conclude that WASH service provision in child care centres may be realised when key actors have a voice and work within networks to demand WASH services from desired networks including the government. We also conclude that developing more direct networks and converting desired and potential networks into direct networks in WASH service provision is critical for the success of WASH service delivery. Lastly, actors in WASH services in childcare centres may need to collaborate in identifying potential avenues for strengthening existing networks that enhance access and quality of WASH services in childcare centres.

Effects of social determinants on children's health in informal settlements in Bangladesh and Kenya through an intersectionality lens: a study protocol.

INTRODUCTION: Several studies have shown that residents of urban informal settlements/slums are usually excluded and marginalised from formal social systems and structures of power leading to disproportionally worse health outcomes compared to other urban dwellers. To promote health equity for slum dwellers, requires an understanding of how their lived realities shape inequities especially for young children 0-4 years old (ie, under-fives) who tend to have a higher mortality compared with non-slum children. In these proposed studies, we aim to examine how key Social Determinants of Health (SDoH) factors at child and household levels combine to affect under-five health conditions, who live in slums in Bangladesh and Kenya through an intersectionality lens. METHODS AND ANALYSIS: The protocol describes how we will analyse data from the Nairobi Cross-sectional Slum Survey (NCSS 2012) for Kenya and the Urban Health Survey (UHS 2013) for Bangladesh to explore how SDoH influence under-five health outcomes in slums within an intersectionality framework. The NCSS 2012 and UHS 2013 samples will consist of 2199 and 3173 under-fives, respectively. We will apply Multilevel Analysis of Individual Heterogeneity and Discriminatory Accuracy approach. Some of SDoH characteristics to be considered will include those of children, head of household, mothers and social structure characteristics of household. The primary outcomes will be whether a child had diarrhoea, cough, fever and acute respiratory infection (ARI) 2 weeks preceding surveys. ETHICS AND DISSEMINATION: The results will be disseminated in international peer-reviewed journals and presented in events organised by the Accountability and Responsiveness in Informal Settlements for Equity consortium and international conferences. Ethical approval was not required for these studies. Access to the NCSS 2012 has been given by Africa Population and Health Center and UHS 2013 is freely available.

Demand and supply-side barriers and opportunities to enhance access to healthcare for urban poor populations in Kenya: a qualitative study.

OBJECTIVE: To explore the barriers to and options for improving access to quality healthcare for the urban poor in Nairobi, Kenya. DESIGN AND PARTICIPANTS: This was a qualitative approach. In-depth interviews (n=12), focus group discussions with community members (n=12) and key informant interviews with health providers and policymakers (n=25) were conducted between August 2019 and September 2020. Four feedback and validation workshops were held in December 2019 and April-June 2021. SETTING: Korogocho and Viwandani urban slums in Nairobi, Kenya. RESULTS: The socioe-conomic status of individuals and their families, such as poverty and lack of health insurance, interact with community-level factors like poor infrastructure, limited availability of health facilities and insecurity; and health system factors such as limited facility opening hours, health providers' attitudes and skills and limited public health resources to limit healthcare access and perpetuate health inequities. Limited involvement in decision-making processes by service providers and other key stakeholders was identified as a major challenge with significant implications on how limited health system resources are managed. CONCLUSION: Despite many targeted interventions to improve the health and well-being of the urban poor, slum residents are still unable to obtain quality healthcare because of persistent and new barriers due to the COVID-19 pandemic. In a devolved health system, paying attention to health services managers' abilities to assess and respond to population health needs is vital. The limited use of existing accountability mechanisms requires attention to ensure that the mechanisms enhance, rather than limit, access to health services for the urban slum residents. The uniqueness of poor urban settings also requires in-depth and focused attention to social determinants of health within these contexts. To address individual, community and system-level barriers to quality healthcare in this and related settings and expand access to health services for all, multisectoral strategies tailored to each population group are needed.

Community advisory committee as a facilitator of health and wellbeing: A qualitative study in informal settlements in Nairobi, Kenya.

Introduction: A range of community engagement initiatives to advance health and wellbeing are currently taking place in informal settlements in low and middle income countries (LMICs), including community and stakeholder meetings, use of radio, film, TV programs and other information, education and communication materials (IECs) organized by different stakeholders. While these initiatives tend to focus on unidirectional flow of information to communities, the need to incorporate initiatives focusing on bi or multi-directional flow of information have been identified. Despite the extensive body of literature on community engagement, the role of Community Advisory Committees (CACs) in advancing health and wellbeing in informal settlements is still a puzzle, occasioned by considerable ambiguity. A community advisory committee is a dedicated group of volunteers to support health and wellbeing needs of their community using a community approach. Researchers and project implementers work in partnership with CACs to successfully implement their activities within the target community. Methods: In this paper, using in-depth interviews, we document the roles of CACs in advancing health and wellbeing in Korogocho and Viwandani informal settlements in Nairobi, Kenya. Results: Study participants described the role of CAC in advancing health and wellbeing through education and awareness creation, advisory roles in research and implementation goals, protecting community interests and acting as gatekeepers and collaborators to community partners. Identified barriers to achieving CAC roles include lack of finance and other field resources, being labeled as organization staff and low involvement by some upcoming and emerging local leaders on issues which involve the CAC constituents. Enablers of CACs in their roles include possession of appropriate skills and values by members; involvement of the community in the selection of members, regular consultative and advisory meetings, representativeness in the composition of CAC membership and knowledge about the community. Conclusion: We conclude that CACs play key roles in advancing health and wellbeing in informal settlements and that existing CACs mechanisms and operations need to be given due consideration by researchers, project implementers and local authorities right from project conceptualization. CACs need recognition beyond consultations and placations during research and project implementation to a veritable social structure for community's social viability and survival as well as partners in development for inclusive urbanization process. While CACs have contributed in advancing health and wellbeing in informal settlements, there is need for a long-term strategy to optimize their impact and reduce puzzles around their roles.

Co-creation and self-evaluation: An accountability mechanism process in water, sanitation and hygiene services delivery in childcare centres in Nairobi's informal settlements.

Background: Accountability strategies are expected to enhance access to water, sanitation and hygiene (WASH) service delivery in low-and middle-income countries (LMIC). Conventional formal social accountability mechanisms (SAMs) for WASH service delivery have been inadequate to meet the needs of residents in informal settlements in LMICs. This has prompted growing interest in alternative informal SAMs (iSAMs) in Nairobi's informal settlements. To date, iSAMs have shown a limited effect, often due to implementation failures and poor contextual fit. In childcare centers in Nairobi's informal settlements, co-creation of the iSAMs process, where parents, childcare managers, researchers and other WASH stakeholders, contribute to the design and implementation of iSAMs, is an approach with the potential to meet urgent WASH needs. However, to our knowledge, no study has documented (1) co-creating iSAMs processes for WASH service delivery in childcare centers and (2) self-evaluation of the co-creation process in the informal settlements. Methods: We used a qualitative approach where we collected data through workshops and focus group discussions to document and inform (a) co-creation processes of SAMs for WASH service delivery in childcare centers and (b) self-evaluation of the co-creation process. We used a framework approach for data analysis informed by Coleman's framework. Results: Study participants co-created an iSAM process that entailed: definition; action and sharing information; judging and assessing; and learning and adapting iSAMs. The four steps were considered to increase the capability to meet WASH needs in childcare centers. We also documented a self-evaluation appraisal of the iSAM process. Study participants described that the co-creation process could improve understanding, inclusion, ownership and performance in WASH service delivery. Negative appraisals described included financial, structural, social and time constraints. Conclusion: We conclude that the co-creation process could address contextual barriers which are often overlooked, as it allows understanding of issues through the 'eyes' of people who experience service delivery issues. Further, we conclude that sustainable and equitable WASH service delivery in childcare centers in informal settlements needs research that goes beyond raising awareness to fully engage and co-create to ensure that novel solutions are developed at an appropriate scale to meet specific needs. We recommend that actors should incorporate co-creation in identification of feasible structures for WASH service delivery in childcare centers and other contexts.

Complementarity of formal and informal actors and their networks in support of vulnerable populations in informal settlements: Governance diaries approach.

Introduction: Beyond several interests and speculations on the relationship between formal and informal actors and their networks in support of vulnerable populations, most studies do not conclusively establish whether the two types of support are substitutes or complements. While informal care and formal care may be substitutes in general, they are complements among the vulnerable groups. Despite how some studies have described complementarity, further insights on the synergy between formal and informal actors and networks are needed to pinpoint how to maximize policy and interventions to alleviate the challenges facing vulnerable groups in informal settlements. Methods: We conducted an ethnography using governance diaries with 24 participants in Korogocho and Viwandani informal settlements in Nairobi, Kenya. The governance diaries approach involved conducting bi-weekly governance in-depth interviews (IDIs) with study participants for 4 months, complemented with observations, reflections, participant diaries and informal discussions. We used framework analysis approach. Findings: Informal actors identified include family, neighbors, friends, community groups and community members, and their direct networks. Formal actors on the other hand included government institutions, individuals and authorities that make policies and rules and their desired and possible networks. Both the formal and informal actors and their networks had complementary roles that were beneficial to the vulnerable populations living and working in informal settlements. The complementarities between formal and informal actors and networks in supporting vulnerable groups were portrayed in roles and responsibilities to the vulnerable groups; rules, regulations and governance in supporting vulnerable groups; knowledge, skills and dynamic workforces among formal and informal actors and their networks; information flow on health and wellbeing to the vulnerable populations; transition of actors in supporting vulnerable groups; availability, access and involvement of formal and informal actors and networks to support vulnerable groups. The complementarities allowed for maximum support of the vulnerable populations than otherwise. Conclusion: We conclude that informal social support is needed regardless of the availability of formal social support. Moreover, a combination of formal and informal actors and related networks are essential to support vulnerable persons. Formal actors should establish, support, or maintain the informal actors and related networks through goodwill and sundry incentives as a vital dimension of building with local community structures and enhancing inclusion, participation and ownership of policy and program interventions by marginalized and vulnerable groups.

Mobile consulting as an option for delivering healthcare services in low-resource settings in low- and middle-income countries: A mixed-methods study.

OBJECTIVE: Remote or mobile consulting is being promoted to strengthen health systems, deliver universal health coverage and facilitate safe clinical communication during coronavirus disease 2019 and beyond. We explored whether mobile consulting is a viable option for communities with minimal resources in low- and middle-income countries. METHODS: We reviewed evidence published since 2018 about mobile consulting in low- and middle-income countries and undertook a scoping study (pre-coronavirus disease) in two rural settings (Pakistan and Tanzania) and five urban slums (Kenya, Nigeria and Bangladesh), using policy/document review, secondary analysis of survey data (from the urban sites) and thematic analysis of interviews/workshops with community members, healthcare workers, digital/telecommunications experts, mobile consulting providers, and local and national decision-makers. Project advisory groups guided the study in each country. RESULTS: We reviewed four empirical studies and seven reviews, analysed data from 5322 urban slum households and engaged with 424 stakeholders in rural and urban sites. Regulatory frameworks are available in each country. Mobile consulting services are operating through provider platforms (n = 5-17) and, at the community level, some direct experience of mobile consulting with healthcare workers using their own phones was reported - for emergencies, advice and care follow-up. Stakeholder willingness was high, provided challenges are addressed in technology, infrastructure, data security, confidentiality, acceptability and health system integration. Mobile consulting can reduce affordability barriers and facilitate care-seeking practices. CONCLUSIONS: There are indications of readiness for mobile consulting in communities with minimal resources. However, wider system strengthening is needed to bolster referrals, specialist services, laboratories and supply chains to fully realise the continuity of care and responsiveness that mobile consulting services offer, particularly during/beyond coronavirus disease 2019.

Impact of the societal response to COVID-19 on access to healthcare for non-COVID-19 health issues in slum communities of Bangladesh, Kenya, Nigeria and Pakistan: results of pre-COVID and COVID-19 lockdown stakeholder engagements.

INTRODUCTION: With COVID-19, there is urgency for policymakers to understand and respond to the health needs of slum communities. Lockdowns for pandemic control have health, social and economic consequences. We consider access to healthcare before and during COVID-19 with those working and living in slum communities. METHODS: In seven slums in Bangladesh, Kenya, Nigeria and Pakistan, we explored stakeholder perspectives and experiences of healthcare access for non-COVID-19 conditions in two periods: pre-COVID-19 and during COVID-19 lockdowns. RESULTS: Between March 2018 and May 2020, we engaged with 860 community leaders, residents, health workers and local authority representatives. Perceived common illnesses in all sites included respiratory, gastric, waterborne and mosquitoborne illnesses and hypertension. Pre-COVID, stakeholders described various preventive, diagnostic and treatment services, including well-used antenatal and immunisation programmes and some screening for hypertension, tuberculosis, HIV and vectorborne disease. In all sites, pharmacists and patent medicine vendors were key providers of treatment and advice for minor illnesses. Mental health services and those addressing gender-based violence were perceived to be limited or unavailable. With COVID-19, a reduction in access to healthcare services was reported in all sites, including preventive services. Cost of healthcare increased while household income reduced. Residents had difficulty reaching healthcare facilities. Fear of being diagnosed with COVID-19 discouraged healthcare seeking. Alleviators included provision of healthcare by phone, pharmacists/drug vendors extending credit and residents receiving philanthropic or government support; these were inconsistent and inadequate. CONCLUSION: Slum residents' ability to seek healthcare for non-COVID-19 conditions has been reduced during lockdowns. To encourage healthcare seeking, clear communication is needed about what is available and whether infection control is in place. Policymakers need to ensure that costs do not escalate and unfairly disadvantage slum communities. Remote consulting to reduce face-to-face contact and provision of mental health and gender-based violence services should be considered.

How to prevent and address safeguarding concerns in global health research programmes: practice, process and positionality in marginalised spaces.

Safeguarding is rapidly rising up the international development agenda, yet literature on safeguarding in related research is limited. This paper shares processes and practice relating to safeguarding within an international research consortium (the ARISE hub, known as ARISE). ARISE aims to enhance accountability and improve the health and well-being of marginalised people living and working in informal urban spaces in low-income and middle-income countries (Bangladesh, India, Kenya and Sierra Leone). Our manuscript is divided into three key sections. We start by discussing the importance of safeguarding in global health research and consider how thinking about vulnerability as a relational concept (shaped by unequal power relations and structural violence) can help locate fluid and context specific safeguarding risks within broader social systems. We then discuss the different steps undertaken in ARISE to develop a shared approach to safeguarding: sharing institutional guidelines and practice; facilitating a participatory process to agree a working definition of safeguarding and joint understandings of vulnerabilities, risks and mitigation strategies and share experiences; developing action plans for safeguarding. This is followed by reflection on our key learnings including how safeguarding, ethics and health and safety concerns overlap; the challenges of referral and support for safeguarding concerns within frequently underserved informal urban spaces; and the importance of reflective practice and critical thinking about power, judgement and positionality and the ownership of the global narrative surrounding safeguarding. We finish by situating our learning within debates on decolonising science and argue for the importance of an iterative, ongoing learning journey that is critical, reflective and inclusive of vulnerable people.

Mobile consulting (mConsulting) and its potential for providing access to quality healthcare for populations living in low-resource settings of low- and middle-income countries.

OBJECTIVE: The poorest populations of the world lack access to quality healthcare. We defined the key components of consulting via mobile technology (mConsulting), explored whether mConsulting can fill gaps in access to quality healthcare for poor and spatially marginalised populations (specifically rural and slum populations) of low- and middle-income countries, and considered the implications of its take-up. METHODS: We utilised realist methodology. First, we undertook a scoping review of mobile health literature and searched for examples of mConsulting. Second, we formed our programme theories and identified potential benefits and hazards for deployment of mConsulting for poor and spatially marginalised populations. Finally, we tested our programme theories against existing frameworks and identified published evidence on how and why these benefits/hazards are likely to accrue. RESULTS: We identified the components of mConsulting, including their characteristics and range. We discuss the implications of mConsulting for poor and spatially marginalised populations in terms of competent care, user experience, cost, workforce, technology, and the wider health system. CONCLUSIONS: For the many dimensions of mConsulting, how it is structured and deployed will make a difference to the benefits and hazards of its use. There is a lack of evidence of the impact of mConsulting in populations that are poor and spatially marginalised, as most research on mConsulting has been undertaken where quality healthcare exists. We suggest that mConsulting could improve access to quality healthcare for these populations and, with attention to how it is deployed, potential hazards for the populations and wider health system could be mitigated.

Modelling changing population distributions: an example of the Kenyan Coast, 1979-2009.

Large-scale gridded population datasets are usually produced for the year of input census data using a top-down approach and projected backward and forward in time using national growth rates. Such temporal projections do not include any subnational variation in population distribution trends and ignore changes in geographical covariates such as urban land cover changes. Improved predictions of population distribution changes over time require the use of a limited number of covariates that are time-invariant or temporally explicit. Here we make use of recently released multi-temporal high-resolution global settlement layers, historical census data and latest developments in population distribution modelling methods to reconstruct population distribution changes over 30 years across the Kenyan Coast. We explore the methodological challenges associated with the production of gridded population distribution time-series in data-scarce countries and show that trade-offs have to be found between spatial and temporal resolutions when selecting the best modelling approach. Strategies used to fill data gaps may vary according to the local context and the objective of the study. This work will hopefully serve as a benchmark for future developments of population distribution time-series that are increasingly required for population-at-risk estimations and spatial modelling in various fields.

The impact of urbanization and population density on childhood Plasmodium falciparum parasite prevalence rates in Africa.

BACKGROUND: Although malaria has been traditionally regarded as less of a problem in urban areas compared to neighbouring rural areas, the risk of malaria infection continues to exist in densely populated, urban areas of Africa. Despite the recognition that urbanization influences the epidemiology of malaria, there is little consensus on urbanization relevant for malaria parasite mapping. Previous studies examining the relationship between urbanization and malaria transmission have used products defining urbanization at global/continental scales developed in the early 2000s, that overestimate actual urban extents while the population estimates are over 15 years old and estimated at administrative unit level. METHODS AND RESULTS: This study sought to discriminate an urbanization definition that is most relevant for malaria parasite mapping using individual level malaria infection data obtained from nationally representative household-based surveys. Boosted regression tree (BRT) modelling was used to determine the effect of urbanization on malaria transmission and if this effect varied with urbanization definition. In addition, the most recent high resolution population distribution data was used to determine whether population density had significant effect on malaria parasite prevalence and if so, could population density replace urban classifications in modelling malaria transmission patterns. The risk of malaria infection was shown to decline from rural areas through peri-urban settlements to urban central areas. Population density was found to be an important predictor of malaria risk. The final boosted regression trees (BRT) model with urbanization and population density gave the best model fit (Tukey test p value <0.05) compared to the models with urbanization only. CONCLUSION: Given the challenges in uniformly classifying urban areas across different countries, population density provides a reliable metric to adjust for the patterns of malaria risk in densely populated urban areas. Future malaria risk models can, therefore, be improved by including both population density and urbanization which have both been shown to have significant impact on malaria risk in this study.

Mapping intra-urban malaria risk using high resolution satellite imagery: a case study of Dar es Salaam.

BACKGROUND: With more than half of Africa's population expected to live in urban settlements by 2030, the burden of malaria among urban populations in Africa continues to rise with an increasing number of people at risk of infection. However, malaria intervention across Africa remains focused on rural, highly endemic communities with far fewer strategic policy directions for the control of malaria in rapidly growing African urban settlements. The complex and heterogeneous nature of urban malaria requires a better understanding of the spatial and temporal patterns of urban malaria risk in order to design effective urban malaria control programs. In this study, we use remotely sensed variables and other environmental covariates to examine the predictability of intra-urban variations of malaria infection risk across the rapidly growing city of Dar es Salaam, Tanzania between 2006 and 2014. METHODS: High resolution SPOT satellite imagery was used to identify urban environmental factors associated malaria prevalence in Dar es Salaam. Supervised classification with a random forest classifier was used to develop high resolution land cover classes that were combined with malaria parasite prevalence data to identify environmental factors that influence localized heterogeneity of malaria transmission and develop a high resolution predictive malaria risk map of Dar es Salaam. RESULTS: Results indicate that the risk of malaria infection varied across the city. The risk of infection increased away from the city centre with lower parasite prevalence predicted in administrative units in the city centre compared to administrative units in the peri-urban suburbs. The variation in malaria risk within Dar es Salaam was shown to be influenced by varying environmental factors. Higher malaria risks were associated with proximity to dense vegetation, inland water and wet/swampy areas while lower risk of infection was predicted in densely built-up areas. CONCLUSIONS: The predictive maps produced can serve as valuable resources for municipal councils aiming to shrink the extents of malaria across cities, target resources for vector control or intensify mosquito and disease surveillance. The semi-automated modelling process developed can be replicated in other urban areas to identify factors that influence heterogeneity in malaria risk patterns and detect vulnerable zones. There is a definite need to expand research into the unique epidemiology of malaria transmission in urban areas for focal elimination and sustained control agendas.

The changing risk of Plasmodium falciparum malaria infection in Africa: 2000-10: a spatial and temporal analysis of transmission intensity.

BACKGROUND: Over a decade ago, the Roll Back Malaria Partnership was launched, and since then there has been unprecedented investment in malaria control. We examined the change in malaria transmission intensity during the period 2000-10 in Africa. METHODS: We assembled a geocoded and community Plasmodium falciparum parasite rate standardised to the age group 2-10 years (PfPR2-10) database from across 49 endemic countries and territories in Africa from surveys undertaken since 1980. The data were used within a Bayesian space-time geostatistical framework to predict PfPR2-10 in 2000 and 2010 at a 1 × 1 km spatial resolution. Population distribution maps at the same spatial resolution were used to compute populations at risk by endemicity class and estimate population-adjusted PfPR2-10 (PAPfPR2-10) for each of the 44 countries for which predictions were possible for each year. FINDINGS: Between 2000 and 2010, the population in hyperendemic (>50% to 75% PfPR2-10) or holoendemic (>75% PfPR2-10) areas decreased from 218·6 million (34·4%) of 635·7 million to 183·5 million (22·5%) of 815·7 million across 44 malaria-endemic countries. 280·1 million (34·3%) people lived in areas of mesoendemic transmission (>10% to 50% PfPR2-10) in 2010 compared with 178·6 million (28·1%) in 2000. Population in areas of unstable or very low transmission (<5% PfPR2-10) increased from 131·7 million people (20·7%) in 2000 to 219·0 million (26·8%) in 2010. An estimated 217·6 million people, or 26·7% of the 2010 population, lived in areas where transmission had reduced by at least one PfPR2-10 endemicity class. 40 countries showed a reduction in national mean PAPfPR2-10. Only ten countries contributed 87·1% of the population living in areas of hyperendemic or holoendemic transmission in 2010. INTERPRETATION: Substantial reductions in malaria transmission have been achieved in endemic countries in Africa over the period 2000-10. However, 57% of the population in 2010 continued to live in areas where transmission remains moderate to intense and global support to sustain and accelerate the reduction of transmission must remain a priority. FUNDING: Wellcome Trust.

Childhood malaria admission rates to four hospitals in Malawi between 2000 and 2010.

INTRODUCTION: The last few years have witnessed rapid scaling-up of key malaria interventions in several African countries following increases in development assistance. However, there is only limited country-specific information on the health impact of expanded coverage of these interventions. METHODS: Paediatric admission data were assembled from 4 hospitals in Malawi reflecting different malaria ecologies. Trends in monthly clinical malaria admissions between January 2000 and December 2010 were analysed using time-series models controlling for covariates related to climate and service use to establish whether changes in admissions can be related to expanded coverage of interventions aimed at reducing malaria infection. RESULTS: In 3 of 4 sites there was an increase in clinical malaria admission rates. Results from time series models indicate a significant month-to-month increase in the mean clinical malaria admission rates at two hospitals (trend P<0.05). At these hospitals clinical malaria admissions had increased from 2000 by 41% to 100%. Comparison of changes in malaria risk and ITN coverage appear to correspond to a lack of disease declines over the period. Changes in intervention coverage within hospital catchments showed minimal increases in ITN coverage from <6% across all sites in 2000 to maximum of 33% at one hospital site by 2010. Additionally, malaria transmission intensity remained unchanged between 2000-2010 across all sites. DISCUSSION: Despite modest increases in coverage of measures to reduce infection there has been minimal changes in paediatric clinical malaria cases in four hospitals in Malawi. Studies across Africa are increasingly showing a mixed set of impact results and it is important to assemble more data from more sites to understand the wider implications of malaria funding investment. We also caution that impact surveillance should continue in areas where intervention coverage is increasing with time, for example Malawi, as decline may become evident within a period when coverage reaches optimal levels.

A global map of dominant malaria vectors.

BACKGROUND: Global maps, in particular those based on vector distributions, have long been used to help visualise the global extent of malaria. Few, however, have been created with the support of a comprehensive and extensive evidence-based approach. METHODS: Here we describe the generation of a global map of the dominant vector species (DVS) of malaria that makes use of predicted distribution maps for individual species or species complexes. RESULTS: Our global map highlights the spatial variability in the complexity of the vector situation. In Africa, An. gambiae, An. arabiensis and An. funestus are co-dominant across much of the continent, whereas in the Asian-Pacific region there is a highly complex situation with multi-species coexistence and variable species dominance. CONCLUSIONS: The competence of the mapping methodology to accurately portray DVS distributions is discussed. The comprehensive and contemporary database of species-specific spatial occurrence (currently available on request) will be made directly available via the Malaria Atlas Project (MAP) website from early 2012.

The changing limits and incidence of malaria in Africa: 1939-2009.

Understanding the historical, temporal changes of malaria risk following control efforts in Africa provides a unique insight into what has been and might be archived towards a long-term ambition of elimination on the continent. Here, we use archived published and unpublished material combined with biological constraints on transmission accompanied by a narrative on malaria control to document the changing incidence of malaria in Africa since earliest reports pre-second World War. One result is a more informed mapped definition of the changing margins of transmission in 1939, 1959, 1979, 1999 and 2009.