Browsing by Subject "sub-Saharan Africa"
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- ItemOpen AccessA bibliometric analysis of childhood immunization research productivity in Africa since the onset of the Expanded Program on Immunization in 1974(BioMed Central, 2013-03-14) Wiysonge, Charles S; Uthman, Olalekan A; Ndumbe, Peter M; Hussey, Gregory DBackground: The implementation of strategic immunization plans whose development is informed by available locally-relevant research evidence should improve immunization coverage and prevent disease, disability and death in Africa. In general, health research helps to answer questions, generate the evidence required to guide policy and identify new tools. However, factors that influence the publication of immunization research in Africa are not known. We, therefore, undertook this study to fill this research gap by providing insights into factors associated with childhood immunization research productivity on the continent. We postulated that research productivity influences immunization coverage. Methods: We conducted a bibliometric analysis of childhood immunization research output from Africa, using research articles indexed in PubMed as a surrogate for total research productivity. We used zero-truncated negative binomial regression models to explore the factors associated with research productivity. Results: We identified 1,641 articles on childhood immunization indexed in PubMed between 1974 and 2010 with authors from Africa, which represent only 8.9% of the global output. Five countries (South Africa, Nigeria, The Gambia, Egypt and Kenya) contributed 48% of the articles. After controlling for population and gross domestic product, The Gambia, Guinea-Bissau and Sao Tome and Principe were the most productive countries. In univariable analyses, the country's gross domestic product, total health expenditure, private health expenditure, and research and development expenditure had a significant positive association with increased research productivity. Immunization coverage, adult literacy rate, human development index and physician density had no significant association. In the multivarable model, only private health expenditure maintained significant statistical association with the number of immunization articles. Conclusions: Immunization research productivity in Africa is highly skewed, with private health expenditure having a significant positive association. However, the current contribution of authors from Africa to global childhood immunization research output is minimal. The lack of association between research productivity and immunization coverage may be an indication of lack of interactive communication between health decision-makers, program managers and researchers; to ensure that immunization policies and plans are always informed by the best available evidence.
- ItemOpen AccessCorrelates of tuberculosis and non-tuberculosis morbidity and immunity in sub-Saharan African HIV-exposed, uninfected infants(2024) Iwase, Saori Christina; Jaspan, Heather; Happel, Anna-UrsulaBackground: Perinatal HIV transmission has been considerably reduced due to successful intervention programs. Consequently, there is a growing population of infants who are HIV-exposed but uninfected (iHEU), particularly in sub-Saharan Africa. These infants experience an increased risk of morbidity compared to infants who are HIV-unexposed and uninfected (iHUU), predominantly due to infectious diseases. Although the mechanisms underlying this increased vulnerability remain unclear, it may be associated with their altered immunity and/or gut microbiota. Bacillus Calmette-Guérin (BCG) vaccination is an effective intervention to prevent severe tuberculosis (TB) disease in children. BCG vaccination also enhances heterologous protective immunity against infections through epigenetic reprogramming of innate immune cells (known as “trained innate immunity”). However, whether iHEU receive comparable protection from BCG induced immunity against TB and non-TB infection as iHUU remains elusive. Gut microbiota plays a critical role in immune development during infancy. A close relationship between gut microbiota and vaccine responses has been reported in iHUU, including tetanus toxoid (TT) vaccination. However, a limited number of studies longitudinally investigated the effect of in utero HIV exposure on the gut microbiota, and results are often conflicting. In addition, not many studies have compared the trajectory of gut microbiota between iHEU and iHUU across multiple countries. While several studies have indicated reduced immune responses against TT vaccination in iHEU compared to iHUU, the interplay between HIV exposure, gut microbiota, and vaccine response is largely unexplored. Aims: In this dissertation, we examined three potential contributing factors that may underlie the higher risk of morbidity observed among iHEU in sub-Saharan Africa. The specific aims were to examine whether BCG affords the same protection against TB infection (TBI) and disease in iHEU (corresponds to Aim 1), effect of HIV exposure on longitudinal gut microbiota composition and its association with TT vaccine response (corresponds to Aim 2), and optimization of epigenetic assay protocol, intended for future investigation of BCG-induced histone modifications in iHEU (corresponds to Aim 3). Methods and results: To assess TBI prevalence among iHEU and iHUU, a total of 418 mother-infant pairs from South Africa and Botswana were included. All infants received BCG vaccination at birth as per standard of care. T-SPOT.TB (ELISpot-based interferon-gamma release assay) was performed using cryopreserved peripheral blood mononuclear cells (PBMCs) from infants aged 9-18 months. The prevalence of TBI did not differ by the infant HIV exposure status, with 10 cases (3.4%) among iHEU and four cases (3.2%) among iHUU, none with symptoms of active TB disease. This trend was the same across two different African countries where the burden of HIV and TB is high. However, because of the lower T-SPOT.TB positivity than initially anticipated, we were under powered to conclude the effect. To assess whether gut microbial succession alters immunity in iHEU, we profiled longitudinal gut microbiota composition and associated this with TT vaccine responses in 354 mother-infant pairs from South Africa and Nigeria. Stool samples were collected at 1 and 15 weeks of life, and 16S ribosomal ribonucleic acid (rRNA) gene sequencing was performed. Plasma IgG anti-tetanus antibody titers were measured by enzyme-linked immunosorbent assay (ELISA). The effect of HIV exposure on infant gut microbiota composition was relatively modest compared to the impact of age and geographical factors. However, HIV exposure and specific gut microbes were independently associated with the TT vaccine response at 15 weeks of age. Results for South Africa and Nigeria differed, possibly due to higher maternal anti-tetanus IgG titers and hence infant baseline titers in Nigeria. To optimize an epigenetic assay that can be applied to infant samples, monocytes and natural killer (NK) cells were isolated from cryopreserved PBMCs using fluorescence-activated cell sorting (FACS). Cleavage Under Targets and Tagmentation (CUT&Tag) was optimized for assessing the histone modifications, acetylation of histone H3 at lysine 27 (H3K27Ac), trimethylation of histone H3 at lysine 4 (H3K4me3), and trimethylation of histone H3 at lysine 27 (H3K27me3; also used as a positive control). The optimized protocol was then applied to a subset of infant samples (n = 14; aged between six and seven weeks). Optimal input cell number, polymerase chain reaction (PCR) cycles, and sequencing depth were carefully determined for the CUT&Tag assay. These adjustments were necessary to achieve the assay's feasibility and data quality. The optimized CUT&Tag protocol and fine-tuned data analysis strategy successfully exhibited its capability to analyze multiple histone modifications using only 5,000 infant monocytes or NK cells as an input sample. Conclusions: Prenatal HIV exposure and gut microbiota may independently influence infant TT vaccine response. This supports the existing notion that iHEU exhibit altered immunity. Although previous studies have indicated that iHEU experience a higher risk of infection than iHUU, our data suggested that BCG vaccination was equally protective against TBI, irrespective of HIV exposure status. The optimized CUT&Tag protocol will offer a useful tool for investigating histone modifications using ultra-low input samples. This will be employed in the future study to explore whether iHEU exhibit comparable epigenetic modifications induced by BCG vaccination as for iHUU, providing valuable insight into whether iHEU receive similar non-specific protection from BCG vaccination compared to iHUU.
- ItemOpen AccessDoes Education Matter for Income Inequality? Evidence from Sub-Saharan Africa(2021) Panton-Ntshona, Sherine; Alhassan, Abdul LatifThe issue of income equality has become of great concern on a global scale. Since the 2008 global financial crisis, economists and other socioeconomic analysts have observed the state of the income and wealth gap between the top ten percent rich and the lower forty percent poor of populations, and its far-reaching impact on the lives of ordinary people. Income inequality has become a global challenge and the effects are felt in both developed and developing countries. The socioeconomic disparity between the rich and poor is pronounced in developing countries, and recent trends of growing inequality are being observed in developed countries. This research examines the effect of education on income inequality and GDP per capita, using a panel dataset of 18 selected sub-Saharan countries for the period from 1994 to 2015. The panel models are estimated, using the fixed effects, random effects and generalised methods of moments estimation techniques. The results show that the relationship of education and its impact on income inequality is dependent on the level of education being assessed. High resource input in tertiary education increases income inequality, while high resource input in lower educational levels reduces income inequality. Overall, increases in government expenditure on education lead to increase in inequality and a fall in GDP per capita. These results show possible inefficiencies in the allocation of educational resources in sub-Saharan countries during the period of investigation. Government spending on education does not reduce inequality or boost income unless it is done efficiently. To reduce income inequality and increase average income, educational resources must be efficiently allocated with priority given to the educational levels of the highest proportions of the population.
- ItemOpen AccessEast African cassava mosaic-like viruses from Africa to Indian ocean islands: molecular diversity, evolutionary history and geographical dissemination of a bipartite begomovirus(BioMed Central Ltd, 2012) De Bruyn, Alexandre; Villemot, Julie; Lefeuvre, Pierre; Villar, Emilie; Hoareau, Murielle; Harimalala, Mireille; Abdoul-Karime, Anli; Abdou-Chakour, Chadhouliati; Reynaud, Bernard; Harkins, Gordon; Varsani, Arvind; Martin, Darren; Lett, Jean-MichelBACKGROUND: Cassava (Manihot esculenta) is a major food source for over 200 million sub-Saharan Africans. Unfortunately, its cultivation is severely hampered by cassava mosaic disease (CMD). Caused by a complex of bipartite cassava mosaic geminiviruses (CMG) species (Family: Geminivirideae; Genus: Begomovirus) CMD has been widely described throughout Africa and it is apparent that CMG's are expanding their geographical distribution. Determining where and when CMG movements have occurred could help curtail its spread and reveal the ecological and anthropic factors associated with similar viral invasions. We applied Bayesian phylogeographic inference and recombination analyses to available and newly described CMG sequences to reconstruct a plausible history of CMG diversification and migration between Africa and South West Indian Ocean (SWIO) islands. RESULTS: The isolation and analysis of 114 DNA-A and 41 DNA-B sequences demonstrated the presence of three CMG species circulating in the Comoros and Seychelles archipelagos (East African cassava mosaic virus, EACMV; East African cassava mosaic Kenya virus, EACMKV; and East African cassava mosaic Cameroon virus, EACMCV). Phylogeographic analyses suggest that CMG's presence on these SWIO islands is probably the result of at least four independent introduction events from mainland Africa occurring between 1988 and 2009. Amongst the islands of the Comoros archipelago, two major migration pathways were inferred: One from Grande Comore to Moheli and the second from Mayotte to Anjouan. While only two recombination events characteristic of SWIO islands isolates were identified, numerous re-assortments events were detected between EACMV and EACMKV, which seem to almost freely interchange their genome components. CONCLUSIONS: Rapid and extensive virus spread within the SWIO islands was demonstrated for three CMG complex species. Strong evolutionary or ecological interaction between CMG species may explain both their propensity to exchange components and the absence of recombination with non-CMG begomoviruses. Our results suggest an important role of anthropic factors in CMGs spread as the principal axes of viral migration correspond with major routes of human movement and commercial trade. Finer-scale temporal analyses of CMGs to precisely scale the relative contributions of human and insect transmission to their movement dynamics will require further extensive sampling in the SWIO region.
- ItemOpen AccessImpact of energy reforms on the poor in Southern Africa(University of Cape Town, 2006) Prasad, Gisela; Visagie, EugeneMost poor households in sub-Saharan Africa cannot afford an electricity connection and even if they get a connection they can only afford to use electricity predominantly for lighting, television and radio. They cannot afford to use it for their most energy-intensive use: cooking. Some countries in Southern Africa have approved policies to assist the poor to get access to electricity. South Africa, Botswana and Malawi have successfully implemented energy reforms and strategies aimed at this, though with different approaches in the three countries. South Africa has a strong economic base and the capacity to provide efficient energy services and highly subsidised electricity access. Botswana’s rural electrification programme is based on cost recovery for the utility: as a result of extending the loan period for the connection fee and adapting the monthly repayment amount to the ability of poor households to pay, electricity connections increased significantly. In Malawi a fixed-rate tariff and a limited-current supply was introduced. The repayment for the ready board was amortised over five years and added to the fixed monthly payment, the amount being adjusted to the ability of the households to pay. In Access II populations were divided into poor and non-poor. These broad categories limited a more differentiated analysis of the impact of power sector reform. In countries which have a high proportion of poor people – in some cases up to 80% of the population – we need to divide them into groups of very poor and not so poor. In this study the poor are ranked by income, and the division into different income groups permitted a more differentiated analysis than just looking at ‘poor’ and ‘non-poor’. The very poor who need further support can be targeted for further assistance. The analysis of the South African data also revealed that the higher urban income groups among the poor can afford to use electricity for most of their energy requirements and need no additional policy support. The analysis also showed how the poor change their energy portfolios as their income improves. The persistent use of fuelwood for cooking among all income groups of poor rural households has remained a matter of concern, particularly as the burning of fuelwood leads to indoor air pollution and affects the health of women and children. The sustainability of fuelwood supplies are also not guaranteed as population increases and fuelwood becomes more commercialised putting pressure on rural areas supplying cities. Even after electrification, households continue to use fuelwood for cooking. The income-differentiated analysis shows that as incomes rise, fewer households use fuelwood and substitute it by kerosene, electricity and gas.
- ItemOpen AccessMortality in patients treated for tuberculous pericarditis in sub-Saharan Africa.(Health & Medical Publishing Group, 2008) Mayosi, Bongani M; Wiysonge, Charles Shey; Ntsekhe, Mpiko; Gumedze, Freedom; Volmink Jimmy A; Maartens, Gary; Aje, Akinyemi; Thomas, Baby M; Thomas, Kandathil M; Awotedu, Abolade A; Bongani, Thembela; Mntla, Phindile; Maritz, Frans; Blackett, Kathleen Ngu; Nkouonlack, Duquesne C; Burch, Vanessa C; Rebe, Kevin; Parrish, Andy; Sliwa, Karen; Vezi, Brian Z; Alam, Nowshad; Brown, Basil G; Gould, Trevor; Visser, Tim; Magula, Nombulelo P; Commerford, Patrick JTuberculous pericarditis is one of the most severe forms of extrapulmonary tuberculosis, causing death or disability in a substantial proportion of affected people.1,2 In Africa, the incidence of tuberculous pericarditis is rising as a result of the HIV epidemic.3 The effect of HIV infection on survival in patients with tuberculous pericarditis is unknown.2,4 Whereas some investigators have suggested that HIV-infected patients with tuberculous pericarditis have a similar outcome to non-infected cases,5 others have shown that there may be an increase in mortality in HIV associated with tuberculous pericarditis.2,6,7 We established a prospective observational study, the Investigation of the Management of Pericarditis in Africa (IMPI Africa) registry, to obtain current information on the diagnosis, management and outcome of patients with presumed tuberculous pericarditis living in sub-Saharan Africa, where the burden of HIV infection is the greatest in the world.4,8-10 In this paper, we report the mortality rate and its predictors during the 6 months of antituberculosis treatment among patients enrolled in the regist
- ItemOpen AccessTask sharing for the care of severe mental disorders in a low-income country (TaSCS): study protocol for a randomised, controlled, non-inferiority trial(BioMed Central, 2016-02-11) Hanlon, Charlotte; Alem, Atalay; Medhin, Girmay; Shibre, Teshome; Ejigu, Dawit A; Negussie, Hanna; Dewey, Michael; Wissow, Lawrence; Prince, Martin; Susser, Ezra; Lund, Crick; Fekadu, AbebawBackground: Task sharing mental health care through integration into primary health care (PHC) is advocated as a means of narrowing the treatment gap for mental disorders in low-income countries. However, the effectiveness, acceptability, feasibility and sustainability of this service model for people with a severe mental disorder (SMD) have not been evaluated in a low-income country. Methods/Design: A randomised, controlled, non-inferiority trial will be carried out in a predominantly rural area of Ethiopia. A sample of 324 people with SMD (diagnoses of schizophrenia, schizoaffective disorder, bipolar disorder or major depressive disorder) with an ongoing need for mental health care will be recruited from 1) participants in a population-based cohort study and 2) people attending a psychiatric nurse-led out-patient clinic. The intervention is a task-sharing model of locally delivered mental health care for people with SMD integrated into PHC delivered over 18 months. Participants in the active control arm will receive the established and effective model of specialist mental health care delivered by psychiatric nurses at an out-patient clinic within a centrally located general hospital. The hypothesis is that people with SMD who receive mental health care integrated into PHC will have a non-inferior clinical outcome, defined as a mean symptom score on the Brief Psychiatric Rating Scale, expanded version, of no more than six points higher, compared to participants who receive the psychiatric nurse-led service, after 12 months. The primary outcome is change in symptom severity. Secondary outcomes are functional status, relapse, service use costs, service satisfaction, drop-out and medication adherence, nutritional status, physical health care, quality of care, medication side effects, stigma, adverse events and cost-effectiveness. Sustainability and costeffectiveness will be further evaluated at 18 months. Randomisation will be stratified by health centre catchment area using random permuted blocks. The outcome assessors and investigators will be masked to allocation status. Discussion: Evidence about the effectiveness of task sharing mental health care for people with SMD in a rural, low-income African country will inform the World Health Organisation’s mental health Gap Action Programme to scale-up mental health care globally.
- ItemOpen AccessThe Burden of Hepatitis B Among People Living with HIV in East Africa: Evidence from 2016?2019 Population-Based HIV Impact Assessment Surveys(2025) Genamo, Mitiku Tamre; Madlala, Hlengiwe; Myer, LandonBackground: Hepatitis B Virus (HBV) co-infection remains a critical public health challenge among people living with HIV (PLWH), particularly in sub-Saharan Africa (SSA). Africa, which is second to Asia in chronic HBV prevalence, globally it was reported approximately 60 million cases in 2017, with nearly 74% of global HBV/HIV co-infections occurring in the SSA region. In East Africa, hepatitis B surface antigen (HBsAg) prevalence rates are as follows: Ethiopia (6.03%), Uganda (9.19%), Kenya (5.16%), Rwanda (6.67%), and Tanzania (7.17%). In countries like Kenya, the infection rates surpass 5%, and Africa accounts for 70% of all new cases of HBV infections globally. Despite extensive research on the HIV epidemic, data on HBV co-infections among PLWH remain limited. Objectives: This study aimed to estimate the prevalence of HBV co-infection among PLWH in East Africa and identify related sociodemographic and clinical factors. Methods: Part A of this Minor dissertation details the research protocol, covering the rationale for the study in the introduction, objectives, methodology, statistical analysis plan, and ethical considerations. Part B provides a comprehensive literature review of studies conducted in sub-Saharan Africa (SSA), exploring the available research on the burden of Hepatitis B and its risk factors among people living with HIV (PLWH). Part C presents the study findings in a journal-formatted manuscript, including results, discussions, limitations, and recommendations. Part D covers the materials used in Parts A, B, and C as appendices, followed by the PLOS ONE journal's instructions to authors. Finally, Part E is the policy brief to inform decision-making. The entire thesis follows the Vancouver referencing style, in line with the requirements of the selected journal for manuscript formatting. A cross-sectional analysis of secondary data from the PHIA surveys conducted in Ethiopia, Kenya, Rwanda, Tanzania, and Uganda from 2016 to 2019 by Colombia university. Data for secondary analysis was extracted from the PHIA dataset between April 2024 – August 2024. The study ii employed stratified multistage probability sampling to select households and participants aged 15– 64 years living with HIV. Data collection, conducted via mobile tablets, covered demographic, clinical, and HIV-related variables. HBV status was assessed through rapid diagnostic tests. Ethical approval was obtained for both primary data collection and secondary analysis per the Helsinki Declaration guidelines. Statistical analysis was performed in R, including descriptive measures, logistic regression, and significance testing (P < 0.05). Results: A total of 4,944 PLWH were included in this analysis, of the total 4,944 PLWH screened for HBV 248 (5.02%) were HBV-positive. The median age of PLWH participants was 36.5 years (IQR: 30– 45), while HBV-negative participants had a median age of 38 years (IQR: 30–47). Males accounted for 42% of HBV-positive cases, compared to 29% among HBV-negative individuals. The overall HBV prevalence among PLWH was 5.02% (95% [CI]: 4.42% – 5.66%), with different country-specific prevalence: Rwanda 3.49% (95% CI: 2.40% – 4.89%), Tanzania 4.29% (95% CI: 0.89% – 12.02%), Kenya (4.99%), Ethiopia 5.54% (95% CI: 3.86% – 7.65%), and Uganda 5.67% (95% CI: 4.65% – 6.84%). Females had higher odds of HBV infection than males (aOR 1.78, P=0.003). Additionally, those who are HBV positive exhibited higher HIV viral loads (≥1,000 copies/mL; 39% vs. 31%) and lower median CD4 counts (455 vs. 488.5 cells/μL). Participants with viral suppression had 1.4 times higher odds of HBV infection than those without viral suppression (OR = 1.40; 95% CI: 1.08–1.82; P = 0.01). Active syphilis infections were more common among HBV-positive individuals (5%) than HBV-negative participants (3%). Conclusion: HBV co-infection remains a significant concern among PLWH in East Africa, with notable country-level variations. It remains a burden that poses an additional challenge to the national health system, which is already battling various infectious and non-infectious diseases. The findings underscore the importance of enhanced HBV screening, vaccination, and integrated treatment approaches to reduce the dual burden of HIV and HBV.
- ItemOpen AccessThe impact of solar ultraviolet radiation on human health in sub-Saharan Africa(2012) Wright, Caradee Y; Norval, Mary; Summers, Beverley; Davids, Lester; Coetzee, Gerrie; Oriowo, Matthew OPhotoprotection messages and 'SunSmart' programmes exist mainly to prevent skin cancers and, more recently, to encourage adequate personal sun exposure to elicit a vitamin D response for healthy bone and immune systems. Several developed countries maintain intensive research networks and monitor solar UV radiation to support awareness campaigns and intervention development. The situation is different in sub-Saharan Africa. Adequate empirical evidence of the impact of solar UV radiation on human health, even for melanomas and cataracts, is lacking, and is overshadowed by other factors such as communicable diseases, especially HIV, AIDS and tuberculosis. In addition, the established photoprotection messages used in developed countries have been adopted and implemented in a limited number of sub-Saharan countries but with minimal understanding of local conditions and behaviours. In this review, we consider the current evidence for sun-related effects on human health in sub-Saharan Africa, summarise published research and identify key issues. Data on the prevalence of human diseases affected by solar UV radiation in all subpopulations are not generally available, financial support is insufficient and the infrastructure to address these and other related topics is inadequate. Despite these limitations, considerable progress may be made regarding the management of solar UV radiation related health outcomes in sub-Saharan Africa, provided researchers collaborate and resources are allocated appropriately.
- ItemOpen AccessWhere do HIV-infected adolescents go after transfer? – Tracking transition/transfer of HIV-infected adolescents using linkage of cohort data to a health information system platform(2017) Davies, Mary-Ann; Tsondai, Priscilla; Tiffin, Nicki; Eley, Brian; Rabie, Helena; Euvrard, Jonathan; Orrell, Catherine; Prozesky, Hans; Wood, Robin; Cogill, Dolphina; Haas, Andreas D; Sohn, Annette H; Boulle, AndrewIntroduction: To evaluate long-term outcomes in HIV-infected adolescents, it is important to identify ways of tracking outcomes after transfer to a different health facility. The Department of Health (DoH) in the Western Cape Province (WCP) of South Africa uses a single unique identifier for all patients across the health service platform. We examined adolescent outcomes after transfer by linking data from four International epidemiology Databases to Evaluate AIDS Southern Africa (IeDEA-SA) cohorts in the WCP with DoH data.