Browsing by Author "Mokaya, Jolynne"

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    Ambient air pollution and health in Sub-Saharan Africa : current evidence, perspectives and a call to action
    (Elsevier, 2019) Katoto, Patrick D. M. C.; Byamungu, Liliane; Brand, Amanda S.; Mokaya, Jolynne; Strijdom, Hans; Goswami, Nandu; De Boever, Patrick; Nawrot, Tim S.; Nemery, Benoit
    Background: People from low- and middle-income countries are disproportionately affected by the global burden of adverse health effects caused by ambient air pollution (AAP). However, data from Sub-Saharan Africa (SSA) are still scarce. We systematically reviewed the literature to describe the existing knowledge on AAP and health outcomes in SSA. Methods: We searched PubMed, Medline-OVID, EMBASE and Scopus databases to identify studies of AAP and health outcomes published up to November 15, 2017. We used a systematic review approach to critically analyze and summarize levels of outdoor air pollutants, and data on health effects associated with AAP. We excluded occupational and indoor exposure studies. Results: We identified 60 articles, with 37 only describing levels of AAP and 23 assessing the association between air pollution and health outcomes. Most studies (75%) addressing the relation between AAP and disease were cross-sectional. In general, exposure data were only obtained for selected cities in the framework of temporary international collaborative research initiatives without structural long-term continuation. Measurements of AAP revealed 10–20 fold higher levels than WHO standards. Of the 23 studies reporting health effects, 14 originated from South Africa, and most countries within SSA contributed no data at all. No studies, except from South Africa, were based on reliable morbidity or mortality statistics at regional or country level. The majority of studies investigated self-reported respiratory symptoms. Children and the elderly were found to be more susceptible to AAP. Conclusion: AAP and its negative health effects have been understudied in SSA compared with other continents. The limited direct measurements of air pollutants indicate that AAP in SAA cities is high compared with international standards. Efforts are needed to monitor AAP in African cities, to identify its main sources, and to reduce adverse health effects by enforcing legislation.
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    Beliefs, knowledge and attitudes towards Parkinson's disease among a Xhosa speaking black population in South Africa : a cross-sectional study
    (Elsevier, 2017-08) Mokaya, Jolynne; Carr, Jonathan; Gray, Keith
    PD is a progressive neurodegenerative disorder characterized by tremor, rigidity, bradykinesia and postural instability [1]. It is classically defined as a motor disorder, however there are a range of non- motor symptoms that occur with advancing age and disease severity[2].
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    Hepatitis B virus infection as a neglected tropical disease
    (Public Library of Science, 2017-10-05) O'Hara, Geraldine A.; McNaughton, Anna L.; Maponga, Tongai; Jooste, Pieter; Ocama, Ponsiano; Chileng, Roma; Mokaya, Jolynne; Liyayi, Mitchell I.; Wachira, Tabitha; Gikungi, David M.; Burbridge, Lela; O'Donnel, Denise; Akiror, Connie S.; Sloan, Derek; Torimiro, Judith; Yindom, Louis Marie; Walton, Robert; Andersson, Monique; Marsh, Kevin; Newton, Robert; Matthews, Philippa C.
    ENGLISH ABSTRACT: The Global Hepatitis Health Sector Strategy is aiming for “elimination of viral hepatitis as a public health threat” by 2030 [1], while enhanced elimination efforts for hepatitis are also promoted under the broader remit of global Sustainable Development Goals (SDGs) [2]. This is an enormous challenge for hepatitis B virus (HBV) given the estimated global burden of 260 million chronic carriers, of whom the majority are unaware of their infection [3] (Fig 1). We here present HBV within the framework for neglected tropical diseases (NTDs) [4] in order to highlight the ways in which HBV meets NTD criteria and to discuss the ways in which the NTD management paradigm could be used to strengthen a unified global approach to HBV elimination [5]. The major burden of morbidity and mortality from HBV is now borne by tropical and subtropical countries [6]. Many African populations epitomize specific vulnerability to HBV [7], so we here focus particular attention on Africa, both through focus on the existing published literature and through presentation of a unique data set of opinion and experience (see S1 Supporting Information). However, the themes we represent are transferable to other low- and middle-income settings and are relevant on the global stage.
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    Hepatitis B virus seroepidemiology data for Africa : modelling intervention strategies based on a systematic review and meta-analysis
    (Public Library of Science, 2021-04-21) McNaughton, Anna L.; Lourenco, Jose; Bester, Phillip Armand; Mokaya, Jolynne; Lumley, Sheila F.; Obolski, Uri; Forde, Donall; Maponga, Tongai G.; Katumba, Kenneth R.; Goedhals, Dominique; Gupta, Sunetra; Seeley, Janet; Newton, Robert; Ocama, Ponsiano; Matthews, Philippa C.
    Background: International Sustainable Development Goals (SDGs) for elimination of hepatitis B virus (HBV) infection set ambitious targets for 2030. In African populations, infant immunisation has been fundamental to reducing incident infections in children, but overall population prevalence of chronic hepatitis B (CHB) infection remains high. In high-prevalence populations, adult catch-up vaccination has sometimes been deployed, but an alternative Test and Treat (T&T) approach could be used as an intervention to interrupt transmission. Universal T&T has not been previously evaluated as a population intervention for HBV infection, despite high-profile data supporting its success with human immunodeficiency virus (HIV). Methods and findings: We set out to investigate the relationship between prevalence of HBV infection and exposure in Africa, undertaking a systematic literature review in November 2019. We identified published seroepidemiology data representing the period 1995–2019 from PubMed and Web of Science, including studies of adults that reported prevalence of both hepatitis B surface antigen (HBsAg; prevalence of HBV infection) and antibody to hepatitis B core antigen (anti-HBc; prevalence of HBV exposure). We identified 96 studies representing 39 African countries, with a median cohort size of 370 participants and a median participant age of 34 years. Using weighted linear regression analysis, we found a strong relationship between the prevalence of infection (HBsAg) and exposure (anti-HBc) (R2 = 0.45, p < 0.001). Region-specific differences were present, with estimated CHB prevalence in Northern Africa typically 30% to 40% lower (p = 0.007) than in Southern Africa for statistically similar exposure rates, demonstrating the need for intervention strategies to be tailored to individual settings. We applied a previously published mathematical model to investigate the effect of interventions in a high-prevalence setting. The most marked and sustained impact was projected with a T&T strategy, with a predicted reduction of 33% prevalence by 20 years (95% CI 30%–37%) and 62% at 50 years (95% CI 57%–68%), followed by routine neonatal vaccination and prevention of mother to child transmission (PMTCT; at 100% coverage). In contrast, the impact of catch-up vaccination in adults had a negligible and transient effect on population prevalence. The study is constrained by gaps in the published data, such that we could not model the impact of antiviral therapy based on stratification by specific clinical criteria and our model framework does not include explicit age-specific or risk-group assumptions regarding force of transmission. Conclusions: The unique data set collected in this study highlights how regional epidemiology data for HBV can provide insights into patterns of transmission, and it provides an evidence base for future quantitative research into the most effective local interventions. In combination with robust neonatal immunisation programmes, ongoing PMTCT efforts, and the vaccination of high-risk groups, diagnosing and treating HBV infection is likely to be of most impact in driving advances towards elimination targets at a population level.
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    Modelling cost-effectiveness of tenofovir for prevention of mother to child transmission of hepatitis B virus (HBV) infection in South Africa
    (BMC (part of Springer Nature), 2019-06-26) Mokaya, Jolynne; Burn, Edward A. O.; Tamandjou Tchuem, Cynthia; Goedhals, Dominique; Barnes, Eleanor J.; Andersson, Monique; Pinedo-Villanueva, Rafael; Matthews, Philippa C.
    Background: International sustainable development goals for the elimination of viral hepatitis as a public health problem by 2030 highlight the need to optimize strategies for prevention, diagnosis and treatment of hepatitis B virus (HBV) infection. An important priority for Africa is to have affordable, accessible and sustainable prevention of mother to child transmission (PMTCT) programmes, delivering screening and treatment for antenatal women and implementing timely administration of HBV vaccine for their babies. Methods: We developed a decision-analytic model simulating 10,000 singleton pregnancies to assess the costeffectiveness of three possible strategies for deployment of tenofovir in pregnancy, in combination with routine infant vaccination: S1: no screening nor antiviral therapy; S2: screening and antiviral prophylaxis for all women who test HBsAg-positive; S3: screening for HBsAg, followed by HBeAg testing and antiviral prophylaxis for women who are HBsAg-positive and HBeAg-positive. Our outcome was cost per infant HBV infection avoided and the analysis followed a healthcare perspective. Results: Based on 10,000 pregnancies, S1 predicts 45 infants would be HBV-infected at six months of age, compared to 21 and 28 infants in S2 and S3, respectively. Relative to S1, S2 had an incremental cost of $3940 per infection avoided. S3 led to more infections and higher costs. Conclusion: Given the long-term health burden for individuals and economic burden for society associated with chronic HBV infection, screening pregnant women and providing tenofovir for all who test HBsAg+ may be a costeffective strategy for South Africa and other low/middle income settings.