Imperial College London

ProfessorSimonGregson

Faculty of MedicineSchool of Public Health

Professor in Demography and Behavioural Science
 
 
 
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Contact

 

+44 (0)20 7594 3279s.gregson

 
 
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Location

 

LG27Praed StreetSt Mary's Campus

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Summary

 

Publications

Publication Type
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262 results found

Wolock T, Flaxman S, Risher K, Dadirai T, Gregson S, Eaton Jet al., 2021, Evaluating distributional regression strategies for modelling self-reported sexual age-mixing, eLife, Vol: 10, Pages: 1-38, ISSN: 2050-084X

The age dynamics of sexual partnership formation determine patterns of sexually transmitted disease transmission and have long been a focus of researchers studying human immunodeficiency virus. Data on self-reported sexual partner age distributions are available from a variety of sources. We sought to explore statistical models that accurately predict the distribution of sexual partner ages over age and sex. We identified which probability distributions and outcome specifications best captured variation in partner age and quantified the benefits of modelling these data using distributional regression. We found that distributional regression with a sinh-arcsinh distribution replicated observed partner age distributions most accurately across three geographically diverse data sets. This framework can be extended with well-known hierarchical modelling tools and can help improve estimates of sexual age-mixing dynamics.

Journal article

Davis K, Perez Guzman P, Hoyer A, Brinks R, Gregg E, Althoff KN, Justice AC, Reiss P, Gregson S, Smit Met al., 2021, Association between HIV infection and hypertension: a global systematic review and meta-analysis of cross-sectional studies, BMC Medicine, Vol: 19, ISSN: 1741-7015

Background:Improved access to effective antiretroviral therapy has meant that people living with HIV (PLHIV) are surviving to older ages. However, PLHIV may be ageing differently to HIV-negative individuals, with dissimilar burdens of non-communicable diseases, such as hypertension. While some observational studies have reported a higher risk of prevalent hypertension among PLHIV compared to HIV-negative individuals, others have found a reduced burden. To clarify the relationship between HIV and hypertension, we identified observational studies and pooled their results to assess whether there is a difference in hypertension risk by HIV status.Methods:We performed a global systematic review and meta-analysis of published cross-sectional studies that examined hypertension risk by HIV status among adults aged > 15 (PROSPERO: CRD42019151359). We searched MEDLINE, EMBASE, Global Health and Cochrane CENTRAL to August 23, 2020, and checked reference lists of included articles. Our main outcome was the risk ratio for prevalent hypertension in PLHIV compared to HIV-negative individuals. Summary estimates were pooled with a random effects model and meta-regression explored whether any difference was associated with study-level factors.Results:Of 21,527 identified studies, 59 were eligible (11,101,581 participants). Crude global hypertension risk was lower among PLHIV than HIV-negative individuals (risk ratio 0.90, 95% CI 0.85–0.96), although heterogeneity between studies was high (I2 = 97%, p < 0.0001). The relationship varied by continent, with risk higher among PLHIV in North America (1.12, 1.02–1.23) and lower among PLHIV in Africa (0.75, 0.68–0.83) and Asia (0.77, 0.63–0.95). Meta-regression revealed strong evidence of a difference in risk ratios when comparing North American and European studies to African ones (North America 1.45, 1.21–1.74; Europe 1.20, 1.03–1.40).Conclusions:Our findings suggest that the r

Journal article

Gregson S, Moorhouse L, Dadirai T, Sheppard H, Mayini J, Beckmann N, Skovdal M, Dzangare J, Moyo B, Maswera R, Pinsky B, Mharakurwa S, Francis I, Mugurungi O, Nyamukapa Cet al., 2021, Comprehensive investigation of sources of misclassification errors in routine HIV testing in Zimbabwe, Journal of the International AIDS Society, Vol: 24, ISSN: 1758-2652

IntroductionMisclassification errors have been reported in rapid diagnostic HIV tests (RDTs) in sub‐Saharan African countries. These errors can lead to missed opportunities for prevention‐of‐mother‐to‐child‐transmission (PMTCT), early infant diagnosis and adult HIV‐prevention, unnecessary lifelong antiretroviral treatment (ART) and wasted resources. Few national estimates or systematic quantifications of sources of errors have been produced. We conducted a comprehensive assessment of possible sources of misclassification errors in routine HIV testing in Zimbabwe.MethodsRDT‐based HIV test results were extracted from routine PMTCT programme records at 62 sites during national antenatal HIV surveillance in 2017. Positive‐ (PPA) and negative‐percent agreement (NPA) for HIV RDT results and the false‐HIV‐positivity rate for people with previous HIV‐positive results (“known‐positives”) were calculated using results from external quality assurance testing done for HIV surveillance purposes. Data on indicators of quality management systems, RDT kit performance under local climatic conditions and user/clerical errors were collected using HIV surveillance forms, data‐loggers and a Smartphone camera application (7 sites). Proportions of cases with errors were compared for tests done in the presence/absence of potential sources of errors.ResultsNPA was 99.9% for both pregnant women (N = 17224) and male partners (N = 2173). PPA was 90.0% (N = 1187) and 93.4% (N = 136) for women and men respectively. 3.5% (N = 1921) of known‐positive individuals on ART were HIV negative. Humidity and temperature exceeding manufacturers’ recommendations, particularly in storerooms (88.6% and 97.3% respectively), and premature readings of RDT output (56.0%) were common. False‐HIV‐negative cases, including interpretation errors, occurred despite staff training and good algorithm compliance, and were not reduced by existing external or internal quality assurance procedures. PPA was l

Journal article

Gregson S, Nyamukapa C, 2021, Did sexual behaviour differences between HIV infection and treatment groups offset the biological preventative effects of ART roll-out in Zimbabwe?, Population Studies: a journal of demography, Vol: 75, Pages: 457-476, ISSN: 0032-4728

HIV incidence declines have been slower than expected during the roll-out of antiretroviral treatment (ART) services in subSaharan African populations suffering generalised epidemics. Using data from a general population, open-cohort, HIV serosurvey (2004-2013), we found evidence for initial reductions in sexual activity and multiple sexual partnerships followed byincreases in the period of ART scale-up, in high HIV-prevalence areas in Manicaland, east Zimbabwe. Recent populationlevel increases in condom use were also recorded but reflected largely high use by the rapidly growing proportion of HIVinfected individuals on treatment. Sexual risk behaviour increased in susceptible uninfected individuals and in untreated – andtherefore more infectious – HIV-infected men, which may have slowed the decline in HIV incidence in this population.Intensified primary HIV prevention programmes, together with strengthened risk screening, referral and support servicesfollowing HIV testing, could help to maximise the impact of ‘test-and-treat’ programmes in reducing new infections.

Journal article

Skovdal M, Maswera R, Kadzura N, Nyamukapa C, Rhead R, Wringe A, Gregson Set al., 2020, Parental obligations, care and HIV treatment: How care for others motivates self-care in Zimbabwe, Journal of Health Psychology, Vol: 25, Pages: 2178-2187, ISSN: 1359-1053

This article examines how parental obligations of care intersect with HIV treatment-seeking behaviours and retention. It draws on qualitative data from eastern Zimbabwe, produced from 65 interviews. Drawing on theories of practice and care ethics, our analysis revealed that norms of parental obligation and care acted as key motivators for ongoing engagement with HIV services and treatment. Parents' attentiveness to the future needs of their children ( caring about), and sense of obligation ( taking care of) and improved ability to care ( caregiving) following treatment initiation, emerged as central to understanding their drive for self-care and engagement with HIV services.

Journal article

Schafer R, Thomas R, Robertson L, Eaton J, Mushati P, Nyamukapa C, Hauck K, Gregson Set al., 2020, Spillover HIV prevention effects of a cash transfer trial in East Zimbabwe: evidence from a cluster-randomised trial and general-population survey, BMC Public Health, Vol: 20, ISSN: 1471-2458

BackgroundBenefits of cash transfers (CTs) for HIV prevention have been demonstrated largely in purposively designed trials, commonly focusing on young women. It is less clear if CT interventions not designed for HIV prevention can have HIV-specific effects, including adverse effects. The cluster-randomised Manicaland Cash Transfer Trial (2010–11) evaluated effects of CTs on children’s (2–17 years) development in eastern Zimbabwe. We evaluated whether this CT intervention with no HIV-specific objectives had unintended HIV prevention spillover effects (externalities).MethodsData on 2909 individuals (15–54 years) living in trial households were taken from a general-population survey, conducted simultaneously in the same communities as the Manicaland Trial. Average treatment effects (ATEs) of CTs on sexual behaviour (any recent sex, condom use, multiple partners) and secondary outcomes (mental distress, school enrolment, and alcohol/cigarette/drug consumption) were estimated using mixed-effects logistic regressions (random effects for study site and intervention cluster), by sex and age group (15–29; 30–54 years). Outcomes were also evaluated with a larger synthetic comparison group created through propensity score matching.ResultsCTs did not affect sexual debut but reduced having any recent sex (past 30 days) among young males (ATE: − 11.7 percentage points [PP] [95% confidence interval: -26.0PP, 2.61PP]) and females (− 5.68PP [− 15.7PP, 4.34PP]), with similar but less uncertain estimates when compared against the synthetic comparison group (males: -9.68PP [− 13.1PP, − 6.30PP]; females: -8.77PP [− 16.3PP, − 1.23PP]). There were no effects among older individuals. Young (but not older) males receiving CTs reported increased multiple partnerships (8.49PP [− 5.40PP, 22.4PP]; synthetic comparison: 10.3PP (1

Journal article

Davis K, Guzman PP, Gregson S, Smit Met al., 2020, Comparing the prevalence of hypertension by HIV status in sub-Saharan African adults: a systematic review and meta-analyses of cross-sectional studies, HIV Glasgow, Publisher: JOHN WILEY & SONS LTD, Pages: 70-70

Background: Some evidence from high-income countries (HICs) suggests that PLHIV experience a higher hypertension prevalence thanHIV-negative individuals. It is unclear whether this is the case in subSaharan Africa (SSA), where large-scale integration of hypertensionservices into HIV programmes is being considered. We examined thehypothesis that living with HIV is associated with higher hypertensionprevalence among adults in SSA.Materials and methods: A systematic review of MEDLINE, EMBASE,Global Health, Cochrane Database of Systematic Reviews, CochraneCentral Register of Controlled Trials and African Journals Online wasperformed, following PRISMA guidelines, to identify cross-sectionalstudies assessing hypertension prevalence in PLHIV and HIV-negativeindividuals >15 years, in SSA. Only studies defining hypertension as“study-ascertained blood pressure ≥140/90 mmHg”, or as “studyascertained blood pressure ≥140/90 mmHg and/or history of antihypertensive medication usage”, were included. Risk of bias assessmentsaddressed adequacy of sample sizes, participant selection and HIV andhypertension status measurement. Random effects models were usedto pool odds ratios (ORs) for prevalent hypertension.Results: We identified 1431 unique studies, of which 12 wereselected for quantitative analysis, providing data on 107 425 participants (49.4% to 69.6% female). The 12 studies collected data between2003 and 2015, in South Africa, Tanzania and Uganda. Risk of biaswas low to moderate, with participant selection a key source of bias.Hypertension prevalence ranged from 5.3% to 51.7% among PLHIVand 8.2% to 65.4% in HIV-negative individuals. Overall, hypertensionprevalence was 41% lower among PLHIV than HIV-negative individuals when using the ≥140/90 mmHg definition (n = 5, OR 0.59, 95%CI 0.55 to 0.64) and 34% lower when using the definition thatincluded medication (n = 7, OR 0.66, 95% CI 0.47 to 0.99).Conclusions: Robust studies comparing hypertension

Conference paper

Davis K, Moorhouse L, Maswera R, Nyamukapa C, Smit M, Gregson Set al., 2020, Examining associations between HIV status and high blood pressure (hypertension) in a high HIV prevalence population in Manicaland, east Zimbabwe: a cross-sectional study of adults, HIV Glasgow, Publisher: JOHN WILEY & SONS LTD, Pages: 69-69

Background: Evidence from high‐income countries indicates that PLHIV experience a higher hypertension prevalence than HIV‐negative individuals. However, it is unclear whether this applies in sub‐Saharan Africa, where behaviour and healthcare access differ. It is also unclear whether reported differences in hypertension prevalence result from socio‐demographic differences between PLHIV and HIV‐negative individuals or from HIV infection and treatment. We analysed data from Manicaland, Zimbabwe, to test the hypothesis that PLHIV had a higher hypertension prevalence than HIV‐negative individuals and assess whether controlling for socio‐demographic factors affected this relationship.Materials and methods: A cross‐sectional study, including interviews and HIV testing, was performed at two urban sites, a town and a roadside trading area (07/2018 to 03/2019). All young women (15 to 24 years) and men (15 to 29 years), and a random sample of 2/3 of older adults were eligible. Individuals were considered hypertensive if they reported ever being diagnosed with hypertension by a doctor/nurse. Logistic regression was used to estimate odds ratios (ORs) for prevalent hypertension, controlling for socio‐demographic confounders. Weights were used in all analyses to compensate for unequal selection probabilities.Results: Among 3404 participants (2169 men; 1235 women), the weighted HIV prevalence was 10.8% (95% CI 9.7 to 11.9%). There were more women among PLHIV (PLHIV: 62.5%, 57.2 to 67.8%; HIV‐negative: 53.2%, 52.2% to 54.2%) and PLHIV were older (>45 years: PLHIV: 40%, 31.8% to 48.2%; HIV‐negative: 25.3%, 23.9% to 26.6%). Hypertension prevalence was higher among PLHIV (20.6%, 16.3% to 25.0%) than HIV‐negative individuals (16.4%, 15.1% to 17.6%; OR 1.33, 1.01 to 1.76, p = 0.048). However, hypertension prevalence was higher in older individuals and women, so after adjusting for age and gender the difference in hypertension between PLHIV and HIV‐negative individuals was non‐signific

Conference paper

Skovdal M, Pickles MR, Hallett TB, Nyamukapa C, Gregson Set al., 2020, Complexities to consider when communicating risk of COVID-19, Public Health, Vol: 186, Pages: 283-285, ISSN: 0033-3506

Journal article

Skovdal M, Beckmann N, Maswera R, Nyamukapa C, Gregson Set al., 2020, Uncertainties, work conditions and testing biases: Potential pathways to misdiagnosis in point-of-care rapid HIV testing in Zimbabwe, PLoS One, Vol: 15, Pages: 1-17, ISSN: 1932-6203

Disconcerting levels of misdiagnosis are common in point-of-care rapid HIV testing programmes in sub-Saharan Africa. To investigate potential pathways to misdiagnosis, we interviewed 28 HIV testers in Zimbabwe and conducted weeklong observations at four testing facilities. Approaching adherence to national HIV testing algorithms as a social and scripted practice, dependent on the integration of certain competences, materials and meanings, our thematic analysis revealed three underlying causes of misdiagnosis: One, a lack of confidence in using certain test-kits, coupled with changes in testing algorithms and inadequate training, fed uncertainties with some testing practices. Two, difficult work conditions, including high workloads and resource-depleted facilities, compounded these uncertainties, and meant testers got distracted or resorted to testing short-cuts. Three, power struggles between HIV testers, and specific client-tester encounters created social interactions that challenged the testing process. We conclude that these contexts contribute to deviances from official and recommended testing procedures, as well as testing and interpretation biases, which may explain cases of misdiagnoses. We caution against user-error explanations to misdiagnosis in the absence of a broader recognition of how broader structural determinants affect HIV testing practices.

Journal article

Marston M, Gregson S, 2020, HIV, ART and fertility in sub-Saharan Africa: pieces still missing in the jigsaw puzzle, Journal of Infectious Diseases, Vol: 221, Pages: 1919-1921, ISSN: 0022-1899

Journal article

Hargreaves JR, Auerbach JD, Hensen B, Johnson S, Gregson Set al., 2020, Strengthening primary HIV prevention: better use of data to improve programmes, develop strategies and evaluate progress, Journal of the International AIDS Society, Vol: 23, Pages: 1-3, ISSN: 1758-2652

Journal article

Schafer R, Thomas R, Rufurwokuda M, Kadzura N, Nyamukapa C, Gregson Set al., 2020, Relationships between changes in HIV risk perception and condom use in east Zimbabwe 2003-2013: Population-based longitudinal analyses, BMC Public Health, Vol: 20, ISSN: 1471-2458

BackgroundPerceiving a personal risk for HIV infection is considered important for engaging in HIV prevention behaviour and often targeted in HIV prevention interventions. However, there is limited evidence for assumed causal relationships between risk perception and prevention behaviour and the degree to which change in behaviour is attributable to change in risk perception is poorly understood. This study examines longitudinal relationships between changes in HIV risk perception and in condom use and the public health importance of changing risk perception.MethodsData on sexually active, HIV-negative adults (15–54 years) were taken from four surveys of a general-population open-cohort study in Manicaland, Zimbabwe (2003–2013). Increasing condom use between surveys was modelled in generalised estimating equations dependent on change in risk perception between surveys. Accounting for changes in other socio-demographic and behavioural factors, regression models examined the bi-directional relationship between risk perception and condom use, testing whether increasing risk perception is associated with increasing condom use and whether increasing condom use is associated with decreasing risk perception. Population attributable fractions (PAFs) were estimated.ResultsOne thousand, nine hundred eighty-eight males and 3715 females participated in ≥2 surveys, contributing 8426 surveys pairs. Increasing risk perception between two surveys was associated with higher odds of increasing condom use (males: adjusted odds ratio [aOR] = 1.39, 95% confidence interval [CI] = 0.85–2.28, PAF = 3.39%; females: aOR = 1.41 [1.06–1.88], PAF = 6.59%), adjusting for changes in other socio-demographic and behavioural factors. Those who decreased risk perception were also more likely to increase condom use (males: aOR = 1.76 [1.12–2.78]; females: aOR = 1.23

Journal article

Davis K, Perez-Guzman P, Hoyer A, Brinks R, Gregg E, Althoff KN, Justice AC, Reiss P, Gregson S, Smit Met al., 2020, Comparing the prevalence of hypertension between HIV-positive and HIV-negative adults: a global systematic review and meta-analysis of cross-sectional studies, 22nd International Workshop on Co-morbidities and Adverse Drug Reactions in HIV, Publisher: SAGE PUBLICATIONS LTD, Pages: 45-46, ISSN: 1359-6535

Conference paper

Thomas R, Skovdal M, Gallizzi M, Schaefer R, Moorhouse L, Nyamukapa C, Maswera R, Mandizvidza P, Hallett T, Gregson Set al., 2020, Improving risk perception and uptake of voluntary medical male circumcision with peer-education sessions and incentives, in Manicaland, East Zimbabwe: study protocol for a pilot randomised trial, Trials, Vol: 21, ISSN: 1745-6215

BackgroundVoluntary medical male circumcision (VMMC) is a key component of combination HIV-prevention programmes. Several high-HIV-prevalence countries in sub-Saharan Africa, including Zimbabwe, are looking to scale up VMMC activities. There is limited evidence on how a combination of social learning from peer education by a role model with different behavioural incentives influences demand for VMMC in such settings.Methods/DesignThis matched-cluster randomised controlled trial with 1740 participants will compare two behavioural incentives against a control with no intervention. In the intervention clusters, participants will participate in an education session delivered by a circumcised young male (“role model”) on the risks of HIV infection and the benefits from medical male circumcision. All participants will receive contributions towards transport costs to access medical male circumcision at participating clinics. Via blocked randomisation, in the intervention clusters participants will be randomly assigned to receive one of two types of incentives – fixed cash payment or lottery payment – both conditional on undergoing surgical VMMC. In two sites, a community-led intervention will also be implemented to address social obstacles and to increase support from peers, families and social structures. Baseline measures of endpoints will be gathered in surveys. Follow-up assessment at 6 months will include self-reported uptake of VMMC triangulated with clinic data.DiscussionThis is the first trial to pilot-test social learning to improve risk perception and self-efficacy and to address the fear of pain associated with VMMC and possible present-biased preferences with front-loaded compensations as well as fixed or lottery-based cash payments. This study will generate important knowledge to inform HIV-prevention policies about the effectiveness of behavioural interventions and incentives, which could be easily scaled-up.Trial registrationThis tria

Journal article

Thomas R, Skovdal M, Galizzi MM, Schaefer R, Moorhouse L, Nyamukapa C, Maswera R, Mandizvidza P, Hallett T, Gregson Set al., 2019, Improving risk perception and uptake of pre-exposure prophylaxis (PrEP) through interactive feedback-based counselling with and without community engagement in young women in Manicaland, East Zimbabwe: study protocol for a pilot randomized trial, Trials, Vol: 20, ISSN: 1745-6215

BackgroundHIV incidence in adolescent girls and young women remains high in sub-Saharan Africa. Progresstowards uptake of HIV prevention methods remains low. Studies of oral PrEP have shown that uptakeand adherence may be low due to low risk perception and ambivalence around using antiretroviralsfor prevention. No evidence exists on whether an interactive intervention aimed at adjusting riskperception and addressing the uncertainty around PrEP will improve uptake. This pilot research trialaims to provide an initial evaluation of the impact of an interactive digital tablet-based counsellingsession, correcting risk perception and addressing ambiguity around availability, usability andeffectiveness of PrEP.Methods/DesignThis is a matched-cluster randomised controlled trial which will compare an interactive tablet-basededucation intervention against a control with no intervention. The study will be implemented in eightsites. In each site, two matched clusters of villages will be created. One cluster will be randomlyallocated to intervention. In two sites a community engagement intervention will also be implementedto address social obstacles and to increase support from peers, families and social structures. 1,200HIV-negative young women 18-24 years, not on PrEP at baseline will be eligible. Baseline measures ofendpoints will be gathered in surveys. Follow-up assessment at six months will include bio-markers ofPrEP uptake and surveys.DiscussionThis will be the first randomized controlled trial to determine whether interactive feedbackcounselling leads to uptake of HIV prevention methods such as PrEP and reduces risky sexualbehaviour. If successful, policymakers could consider such an intervention in school-based educationcampaigns or as post- HIV-testing counselling for young people.Trial RegistrationThis trial has been registered on clinicaltrials.gov on 21/06/2018 (identifier: NCT03565575).https://clinicaltrials.gov/ct2/show/NCT03565575

Journal article

Moran M, Skovdal M, Mpandaguta E, Maswera R, Kadzura N, Dzamatira F, Nyamukapa C, Gregson S, Tlhajoane Met al., 2019, The temporalities of policymaking: The case of HIV test-and-treat policy adoption in Zimbabwe, Health & Place, ISSN: 1353-8292

Despite calls for “rapid adoption” of global health policies and treatment guidelines; there is little understanding of the factors that help accelerate their adoption and implementation. Drawing on in-depth interviews with sixteen Zimbabwean policymakers, we unpack how different factors, rhythmic experiences and epochal practices come together to shape the speeding up and slowing down of test-and-treat implementation in Zimbabwe. We present an empirically derived framework for the temporal analysis of policy adoption and argue that such analysis can help highlight the multiple and messy realities of policy adoption and implementation - supporting future calls for ‘rapid’ policy adoption.

Journal article

Schaefer R, Thomas R, Nyamukapa C, Maswera R, Kadzura N, Gregson Set al., 2019, Accuracy of HIV risk perception in east Zimbabwe 2003-2013, AIDS and Behavior, Vol: 23, Pages: 2199-2209, ISSN: 1090-7165

Risk perception for HIV infection is an important determinant for engaging in HIV prevention behaviour. We investigate the degree to which HIV risk perception is accurate, i.e. corresponds to actual HIV infection risks, in a general-population open-cohort study in Zimbabwe (2003–2013) including 7201 individuals over 31,326 person-years. Risk perception for future infection (no/yes) at the beginning of periods between two surveys was associated with increased risk of HIV infection (Cox regression hazard ratio = 1.38 [1.07–1.79], adjusting for socio-demographic characteristics, sexual behaviour, and partner behaviour). The association was stronger among older people (25+ years). This suggests that HIV risk perception can be accurate but the higher HIV incidence (1.27 per 100 person-years) illustrates that individuals may face barriers to HIV prevention behaviour even when they perceive their risks. Gaps in risk perception are underlined by the high incidence among those not perceiving a risk (0.96%), low risk perception even among those reporting potentially risky sexual behaviour, and, particularly, lack of accuracy of risk perception among young people. Innovative interventions are needed to improve accuracy of risk perception but barriers to HIV prevention behaviours need to be addressed too, which may relate to the partner, community, or structural factors.

Journal article

Moorhouse L, Schaefer R, Thomas R, Nyamukapa C, Skovdal M, Hallett T, Gregson Set al., 2019, Application of the HIV prevention cascade to identify, develop,and evaluate interventions to improve use of prevention methods:Examples from a study in east Zimbabwe, Journal of the International AIDS Society, Vol: 22, Pages: 86-92, ISSN: 1758-2652

Introduction: The HIV prevention cascade could be used in developing interventions to strengthen implementation of efficacious HIV prevention methods but its practical utility needs to be demonstrated. We propose a standardised approach to using the cascade to guide identification and evaluation of interventions and demonstrate its feasibility through a project to develop interventions to improve use of HIV prevention methods by adolescent girls and young women (AGYW) and potential male partners in east Zimbabwe.Discussion: We propose a six-step approach to using a published generic HIV prevention cascade formulation to develop interventions to increase motivation to use, access to and effective use of an HIV prevention method. The six steps are: (1) measure the HIV prevention cascade for the chosen population and method; (2) identify gaps in the cascade; (3) identify explanatory factors (barriers) contributing to observed gaps; (4) review literature to identify relevant theoretical frameworks and interventions; (5) tailor interventions to the local context; and (6) implement and evaluate the interventions using the cascade steps and explanatory factors as outcome indicators in the evaluation design. In the Zimbabwe example, steps 1-5 aided development of four interventions to overcome barriers to effective use of PrEP in AGYW (15-24 years) and VMMC in male partners (15-29). For young men, prevention cascade analyses identified gaps in motivation and access (due to transport costs/lost income) as barriers to VMMC uptake, so an intervention was designed including financial incentives and an education session. For AGYW, gaps in motivation (particularly lack of risk perception) and access were identified as barriers to PrEP uptake: an interactive counselling game was developed addressing these barriers. A text messaging intervention was developed to improve adherence to PrEP among AGYW, addressing reasons underlying lack of effective PrEP use through improving the capa

Journal article

Schaefer R, Gregson S, Benedikt C, 2019, Widespread changes in sexual behaviour in eastern and southern Africa: Challenges to achieving global HIV targets? Longitudinal analyses of nationally representative surveys, Journal of the International AIDS Society, Vol: 22, ISSN: 1758-2652

Introduction: Sexual behaviour change contributed to reductions in HIV incidence in eastern and southern Africa between 1990 and 2010. More recently, there are indications that non-regular partnerships have increased. However, the effect of these increases on population-level risks for HIV and other sexually transmitted infections could have been reduced by simultaneous increases in condom use. We describe recent trends in sexual behaviour and condom use within the region and assess their combined effects on population levels of sexual risk.Methods: Nationally representative Demographic and Health Survey data on sexually active males and females (15-49 years) were used for 11 eastern and southern African countries (≥3 surveys for each country; 1999-2016) to describe trends in sexual behaviour (multiple, non-regular, and casual sexual partnerships; condom use; age at first sex). Logistic regressions tested for statistical significance of changes. Analyses were stratified by sex.Results: Recent increases in multiple, non-regular, and/or casual partnerships can be found for males in ten countries and, for females, in nine countries; five countries exhibited recent decreases in age of sexual debut. Reduction in sex without condoms with non-regular partners was observed in six countries for males and eight for females. Changes in the proportion of the overall population reporting condomless sex with non-regular partners varied between countries, with declines in six countries and increases in three.Conclusions: Extensive change in sexual behaviour occurred across eastern and southern Africa during the period of scale-up of antiretroviral therapy programmes. This includes increasing multiple and non-regular partnerships, but their potential effects on population-level sexual risks were often offset by parallel increases in condom use. Strengthening condom programmes and reintegrating communication about behavioural dimensions into combination prevention programmes coul

Journal article

Rhead R, Skovdal M, Takaruza A, Maswera R, Nyamukapa C, Gregson Set al., 2019, The multidimensionality of masculine norms in east Zimbabwe: implications for HIV prevention, testing and treatment, AIDS, Vol: 33, Pages: 537-546, ISSN: 0269-9370

Background: Research and intervention studies suggest that men face challenges in using HIV services in sub-Saharan Africa. To address these challenges, quantitative measurements are needed to establish the individual-level determinants of masculine norms and their implications for HIV prevention and treatment programmes. Methods: Survey questions for four masculine norms identified in qualitative research were included in a general-population survey of 3116 men in east Zimbabwe, 2012-2013. Two sets of regression analyses were conducted in an SEM framework to examine: 1) which socio-demographic characteristics were associated with high scores on each masculinity factor; and 2) how high scores on these masculinity factors differed in their associations with sexual risk behaviour and use of HIV services. Findings: Socio-demographic characteristics associated with high factor scores differed between masculine norms. In HIV-negative men, more men with scores exceeding one standard deviation above the mean (high scorers) for Anti-femininity than men with scores under one standard deviation below the mean (low scorers) took steps to avoid infection (61% versus 54%, p<0.01). Fewer high than low scorers on Social status reported a recent HIV test (69% versus 74%, p=0.04). In HIV-positive men, more high scorers on Sex drive had been diagnosed (85% versus 61%, p=0.02), were on antiretroviral treatment (91% versus 62%, p=0.04), and were in AIDS groups (77% versus 46% p=0.03).Conclusions: HIV treatment, prevention programmes looking to engage men must consider the multi-dimensionality of masculine norms. The scale developed in this study is robust and can be used by other large multi-purpose surveys to examine masculine social norms.

Journal article

Skovdal M, Ssekubugu R, Nyamukapa C, Seeley J, Renju J, Wamoyi J, Moshabela M, Ondenge K, Wringe A, Gregson S, Zaba Bet al., 2019, The rebellious man: next-of-kin accounts of the death of a male relative on antiretroviral therapy in sub-Saharan Africa, Global Public Health, Vol: 14, Pages: 1252-1263, ISSN: 1744-1692

The HIV response is hampered by many obstacles to progression along the HIV care cascade, with men, in particular, experiencing different forms of disruption. One group of men, whose stories remain untold, are those who have succumbed to HIV-related illness. In this paper, we explore how next-of-kin account for the death of a male relative. We conducted 26 qualitative after-death interviews with family members of male PLHIV who had recently died from HIV in health and demographic surveillance sites in Malawi, Tanzania, Kenya, Uganda, Zimbabwe and South Africa. The next-of-kin expressed frustration about the defiance of their male relative to disclose his HIV status and ask for support, and attributed this to shame, fear and a lack of self-acceptance of HIV diagnosis. Next-of-kin painted a picture of their male relative as rebellious. Some claimed that their deceased relative deliberately ignored instructions received by the health worker. Others described their male relatives as unable to maintain caring relationships that would avail day-to-day treatment partners, and give purpose to their lives. Through these accounts, next-of-kin vocalised the perceived rebellious behaviour of these men, and in the process of doing so neutralised their responsibility for the premature death of their relative.

Journal article

Schaefer R, Gregson S, Fearon E, Hensen B, Hallett T, Hargreaves JRet al., 2019, HIV prevention cascades: A unifying framework to replicate the successes of treatment cascades, The Lancet HIV, Vol: 6, ISSN: 2405-4704

Many countries are off track to meet targets for reduction of new HIV infections. HIV prevention cascades have been proposed to assist in the implementation and monitoring of HIV prevention programmes by identifying gaps in the steps required for effective use of prevention methods, similar to HIV treatment cascades. However, absence of a unifying framework impedes widespread use of prevention cascades. Building on a series of consultations, we propose an HIV prevention cascade that consists of three key domains of motivation, access, and effective use in a priority population. This three step cascade can be used for routine monitoring and advocacy, particularly by attaching 90-90-90-style targets. Further characterisation of reasons for gaps across motivation, access, or effective use allows for a comprehensive framework that guides identification of relevant responses and platforms for interventions. Linkage of the prevention cascade, reasons for gaps, and interventions reconciles the different requirements of prevention cascades, providing a unifying framework.

Journal article

Tlhajoane M, Masoka T, Mpandaguta E, Rhead R, Church K, Wringe A, Kadzura N, Arinaminpathy N, Nyamukapa C, Schur N, Mugurungi O, Skovdal M, Eaton J, Gregson Set al., 2018, A longitudinal review of national HIV policy and progress made in health facility implementation in eastern Zimbabwe, Health Research Policy and Systems, Vol: 16, ISSN: 1478-4505

BackgroundIn recent years, WHO has made major changes to its guidance on the provision of HIV care and treatment services. We conducted a longitudinal study from 2013 to 2015 to establish how these changes have been translated into national policy in Zimbabwe and to measure progress in implementation within local health facilities.MethodsNational HIV programme policy guidelines published between 2003 and 2013 (n = 9) and 2014 and 2015 (n = 5) were reviewed to assess adoption of WHO recommendations on HIV testing services, prevention of mother-to-child transmission (PMTCT) of HIV, and provision of antiretroviral therapy (ART). Changes in local implementation of these policies over time were measured in two rounds of a survey conducted at 36 health facilities in Eastern Zimbabwe in 2013 and 2015.ResultsHigh levels of adoption of WHO guidance into national policy were recorded, including adoption of new recommendations made in 2013–2015 to introduce PMTCT Option B+ and to increase the threshold for ART initiation from CD4 ≤ 350 cells/mm3 to ≤ 500 cells/mm3. New strategies to implement national HIV policies were introduced such as the decentralisation of ART services from hospitals to clinics and task-shifting of care from doctors to nurses. The proportions of health facilities offering free HIV testing and counselling, PMTCT (including Option B+) and ART services increased substantially from 2013 to 2015, despite reductions in numbers of health workers. Provision of provider-initiated HIV testing remained consistently high. At least one test-kit stock-out in the prior year was reported in most facilities (2013: 69%; 2015: 61%; p = 0.44). Stock-outs of first-line ART and prophylactic drugs for opportunistic infections remained low. Repeat testing for HIV-negative individuals within 3 months decreased (2013: 97%; 2015: 72%; p = 0.01). Laboratory testing remained low across both surve

Journal article

Tlhajoane M, Eaton JW, Takaruza A, Rhead R, Maswera R, Schur N, Sherr L, Nyamukapa C, Gregson Set al., 2018, Prevalence and associations of psychological distress, HIV infection and HIV care service utilization in East Zimbabwe, AIDS and Behavior, Vol: 22, Pages: 1485-1495, ISSN: 1090-7165

The correlation between mental health and sexual risk behaviours for HIV infection remains largely unknown in low and middle income settings. The present study determined the prevalence of psychological distress (PD) in a sub-Saharan African population with a generalized HIV epidemic, and investigated associations with HIV acquisition risk and uptake of HIV services using data from a cross-sectional survey of 13,252 adults. PD was measured using the Shona Symptom Questionnaire. Logistic regression was used to measure associations between PD and hypothesized covariates. The prevalence of PD was 4.5% (95% CI 3.9-5.1%) among men, and 12.9% (95% CI 12.2-13.6%) among women. PD was associated with sexual risk behaviours for HIV infection and HIV-infected individuals were more likely to suffer from PD. Amongst those initiated on anti-retroviral therapy, individuals with PD were less likely to adhere to treatment (91 vs. 96%; age- and site-type-adjusted odds ratio = 0.38; 95% CI 0.15, 0.99). Integrated HIV and mental health services may enhance HIV care and treatment outcomes in high HIV-prevalence populations in sub-Saharan Africa.

Journal article

Smit M, Olney J, Ford NP, Vitoria M, Gregson S, Vassall A, Hallett TBet al., 2018, The growing burden of non-communicable disease among persons living with HIV in Zimbabwe, AIDS, Vol: 32, Pages: 773-782, ISSN: 0269-9370

Objectives:We aim to characterize the future noncommunicable disease (NCD)burden in Zimbabwe to identify future health system priorities.Methods:We developed an individual-based multidisease model for Zimbabwe,simulating births, deaths, infection with HIV and progression and key NCD [asthma,chronic kidney disease (CKD), depression, diabetes, hypertension, stroke, breast,cervical, colorectal, liver, oesophageal, prostate and all other cancers]. The modelwas parameterized using national and regional surveillance and epidemiological data.Demographic and NCD burden projections were generated for 2015 to 2035.Results:The model predicts that mean age of PLHIV will increase from 31 to 45 yearsbetween 2015 and 2035 (compared with 20 –26 in uninfected individuals). Conse-quently, the proportion suffering from at least one key NCD in 2035 will increase by26% in PLHIV and 6% in uninfected. Adult PLHIV will be twice as likely to suffer from atleast one key NCD in 2035 compared with uninfected adults; with 15.2% of all keyNCDs diagnosed in adult PLHIV, whereas contributing only 5% of the Zimbabweanpopulation. The most prevalent NCDs will be hypertension, CKD, depression andcancers. This demographic and disease shift in PLHIV is mainly because of reductions inincidence and the success of ART scale-up leading to longer life expectancy, and to alesser extent, the cumulative exposure to HIV and ART.Conclusion:NCD services will need to be expanded in Zimbabwe. They will need tobe integrated into HIV care programmes, although the growing NCD burden amongstuninfected individuals presenting opportunities for additional services developedwithin HIV care to benefit HIV-negative persons.

Journal article

Rhead R, Elmes J, Otobo E, Nhongo K, Takaruza A, White P, Nyamukapa C, Gregson Set al., 2018, Do female sex workers have lower uptake of HIV treatment services than non-sex-workers? A cross-sectional study from East Zimbabwe, BMJ Open, Vol: 8, ISSN: 2044-6055

Objective Globally, HIV disproportionately affects female sex workers (FSWs) yet HIV treatment coverage is suboptimal. To improve uptake of HIV services by FSWs, it is important to identify potential inequalities in access and use of care and their determinants. Our aim is to investigate HIV treatment cascades for FSWs and non-sex workers (NSWs) in Manicaland province, Zimbabwe, and to examine the socio-demographic characteristics and intermediate determinants that might explain differences in service uptake.Methods Data from a household survey conducted in 2009–2011 and a parallel snowball sample survey of FSWs were matched using probability methods to reduce under-reporting of FSWs. HIV treatment cascades were constructed and compared for FSWs (n=174) and NSWs (n=2555). Determinants of service uptake were identified a priori in a theoretical framework and tested using logistic regression.Results HIV prevalence was higher in FSWs than in NSWs (52.6% vs 19.8%; age-adjusted OR (AOR) 4.0; 95% CI 2.9 to 5.5). In HIV-positive women, FSWs were more likely to have been diagnosed (58.2% vs 42.6%; AOR 1.62; 1.02–2.59) and HIV-diagnosed FSWs were more likely to initiate ART (84.9% vs 64.0%; AOR 2.33; 1.03–5.28). No difference was found for antiretroviral treatment (ART) adherence (91.1% vs 90.5%; P=0.9). FSWs’ greater uptake of HIV treatment services became non-significant after adjusting for intermediate factors including HIV knowledge and risk perception, travel time to services, physical and mental health, and recent pregnancy.Conclusion FSWs are more likely to take up testing and treatment services and were closer to achieving optimal outcomes along the cascade compared with NSWs. However, ART coverage was low in all women at the time of the survey. FSWs’ need for, knowledge of and proximity to HIV testing and treatment facilities appear to increase uptake.

Journal article

Gregson S, Mugurungi O, Eaton J, Takaruza A, Rhead R, Maswera R, Mutsangwa J, Mayini J, Skovdal M, Schaefer R, Hallett T, Sherr L, Munyati S, Mason P, Campbell C, Garnett G, Nyamukapa Cet al., 2017, Documenting and explaining the HIV decline in east Zimbabwe: the Manicaland General Population Cohort, BMJ Open, Vol: 7, ISSN: 2044-6055

Purpose: The Manicaland Cohort was established to provide robust scientific data on HIV prevalence and incidence, patterns of sexual risk behaviour, and the demographic impact of HIV in a sub-Saharan African population subject to a generalised HIV epidemic. The aims were later broadened to include provision of data on the coverage and effectiveness of national HIV control programmes including antiretroviral treatment (ART).Participants: General population open cohort located in 12 sites in Manicaland, east Zimbabwe, representing 4 major socio-economic strata (small towns, agricultural estates, roadside settlements, and subsistence farming areas). 9,109 of 11,453 (79.5%) eligible adults (men 17-54 years; women 15-44 years) were recruited in a phased household census between July 1998 and January 2000. Five rounds of follow-up of the prospective household census and the open cohort were conducted at 2 or 3 year intervals between July 2001 and November 2013. Follow-up rates among surviving residents ranged between 77.0% (over 3 years) and 96.4% (2 years). Findings to date: HIV prevalence was 25.1% at baseline and had a substantial demographic impact with 10-fold higher mortality in HIV-infected adults than in uninfected adults and a reduction in the growth rate in the worst affected areas (towns) from 2.9% to 1.0%pa. HIV infection rates have been highest in young adults with earlier commencement of sexual activity and in those with older sexual partners and larger numbers of lifetime partners. HIV prevalence has since fallen to 15.8% and HIV incidence has also declined from 2.1% (1998-2003) to 0.63% (2009-2013) largely due to reduced sexual risk behaviour. HIV-associated mortality fell substantially after 2009 with increased availability of ART

Journal article

Pufall E, Eaton JW, Robertson L, Mushati P, Nyamukapa C, Gregson Set al., 2017, Education, substance use, and HIV risk among orphaned adolescents in Eastern Zimbabwe, Vulnerable Children and Youth Studies, Vol: 12, Pages: 360-374, ISSN: 1745-0136

There is a growing interest in education as a means to reduce HIV infection in vulnerable children in sub-Saharan Africa; however, the mechanisms by which education reduces HIV infection remain uncertain. Substance use has been associated with high-risk sexual behaviour and could lie on the causal pathway between education and HIV risk. Therefore, we used multivariable regression to measure associations between: (i) orphanhood and substance use (alcohol, recreational drugs, and smoking), (ii) substance use and sexual risk behaviours, and (iii) school enrolment and substance use, in adolescents aged 15–19 years, in Eastern Zimbabwe. We found substance use to be low overall (6.4%, 3.2%, and 0.9% of males reported alcohol, drug, and cigarette use; <1% of females reported any substance use), but was more common in male maternal and double orphans than non-orphans. Substance use was positively associated with early sexual debut, number of sexual partners, and engaging in transactional sex, while school enrolment was associated with lower substance use in males. We conclude that education may reduce sexual risk behaviours and HIV infection rates among male adolescents in sub-Saharan Africa, in part, by reducing substance abuse.

Journal article

Schaefer R, Gregson S, Eaton JW, Mugurungi O, Rhead R, Takaruza A, Maswera R, Nyamukapa Cet al., 2017, Age-disparate relationships and HIV incidence in adolescent girls and young women: evidence from a general-population cohort in Zimbabwe, AIDS, Vol: 31, Pages: 1461-1470, ISSN: 0269-9370

Objective: Age-disparate sexual relationships with older men may drive high rates of HIV acquisition in young women in sub-Saharan Africa but evidence is limited. We investigate the association between age-disparate relationships and HIV incidence in Manicaland, Zimbabwe.Design: A general-population open-cohort study (six surveys) (1998-2013).Methods: 3746 young women aged 15-24 years participated in consecutive surveys and were HIV-negative at the beginning of inter-survey periods. Last sexual partner age difference and age-disparate relationships (inter-generational [≥10 years age difference] and intra-generational [5-9 years] versus age-homogeneous [0-4 years]) were tested for associations with HIV incidence in Cox regressions. A proximate determinants framework was used to explore factors possibly explaining variations in the contribution of age-disparate relationships to HIV incidence between populations and over time.Results: 126 HIV infections occurred over 8777 person-years (1.43 per 100 person-years; 95% confidence interval=1.17-1.68). 65% of women reported partner age differences of ≥5 years. Increasing partner age differences were associated with higher HIV incidence (adjusted hazard ratio [aHR]=1.05 [1.01-1.09]). Inter-generational relationships tended to increase HIV incidence (aHR=1.78 [0.96-3.29]) but not intra-generational relationships (aHR=0.91 [0.47-1.76]). Secondary education was associated with reductions in inter-generational relationships (adjusted odds ratio [aOR]=0.49 [0.36-0.68]). Inter-generational relationships were associated with partners having concurrent relationships (aOR=2.59 [1.81-3.70]) which tended to increase HIV incidence (aHR=1.74 [0.96-3.17]). Associations between age-disparity and HIV incidence did not change over time.Conclusions: Sexual relationships with older men expose young women to increased risk of HIV acquisition in Manicaland, which did not change over time, even with introduction of antiretroviral therapy.

Journal article

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