High-risk sexual behaviour among HIV–negative MSM in England: behavioural data to inform HIV prevention

This thesis would not have been possible without Fiona Burns and Anthony Nardone, my two main supervisors. They have been there every step of the way, always patient and always ready to read another draft of the thesis chapters. I have learnt so much from them. They have contributed hours of reading and somehow managed to always come back with constructive and supportive feedback. I also cannot thank them enough for their moral support. They have understood the challenges associated with meeting the demands of the PhD and raising a young family and have helped me get through those moments where it all felt too challenging. I would also like to thank Graham Hart and Noel Gill, my other supervisors. They have both been there to ask the right questions including the “so what?” question, to challenge me and ensure the PhD was on the right track. Their combined guidance and oversight has been invaluable to this thesis. It has been a pleasure to work with them. I would like to thank all of my collaborators and colleagues for their insights and contributions over the years. It has been my privilege to work with all these individuals and teams both within UCL and Public Health England but also those beyond. The HIV team have been patient with my part-time working arrangements while the GUMCAD team have had to endure endless questions about the surveillance system. I also want to thank those who participated in the behavioural study. It was not an easy endeavour but thank you for being enthusiastic and persevering. Special thanks go to Menelaos Pavlou for his support and patience with all my questions about risk predictions models. Thanks also go to Carina and Maryam for the joint efforts in the SANTE project and to Maryam for sharing her knowledge of the viva. It has also been a pleasure to share the PhD journey with Sarah, Ellie, Ibi, Jess, Vicky, Meaghan, Sara, Adamma and David. Your inputs and support have enriched my PhD experience! Thank you. I would like to thank my family and friends who have been brilliant with their encouragements, and sometimes much required pep talks. I especially want to thank my family for being there and ungrudgingly providing child care when the PhD took over my life. And finally, to Anil: you have been unwavering, patient and supportive beyond what words can describe. Thank you for taking charge at bath- and bedtimes and keeping me supplied with food and drink. I am grateful (and probably quite a lucky girl!) that you have been by my side through this journey

Does community-based point of care HIV testing reduce late HIV diagnosis? A retrospective study in England and Wales.

The objective of this study was to investigate if patients diagnosed in community clinics have higher baseline CD4 cell counts than those diagnosed in Genitourinary medicine (GUM)/HIV clinics. We undertook a retrospective review of baseline CD4 cell counts for patients receiving a reactive HIV test in community-testing clinics. Eleven local HIV clinics were contacted to determine the baseline CD4 cell counts of these patients. Baseline CD4 cell counts of those diagnosed in the community were compared with mean local GUM/HIV clinic and median national baseline CD4 cell count for their year of diagnosis. Clients diagnosed in community settings had a mean baseline CD4 cell count of 481 cells/mm3 (SD 236 cells/mm3) and median baseline of 483 cells/mm3 (interquartile range 311-657 cells/mm3). This was significantly higher than those diagnosed in the GUM/HIV clinic local to the community-testing site (mean baseline CD4 397 cells/mm3, p = 0.014) and the national median for that year (336 cells/mm3, p < 0.001). HIV testing in community settings identifies patients at an earlier stage of infection than testing in clinical settings

Economic evaluation of HIV pre-exposure prophylaxis among men-who-have-sex-with-men in England in 2016.

Clinical effectiveness of pre-exposure prophylaxis (PrEP) for preventing HIV acquisition in men who have sex with men (MSM) at high HIV risk is established. A static decision analytical model was constructed to inform policy prioritisation in England around cost-effectiveness and budgetary impact of a PrEP programme covering 5,000 MSM during an initial high-risk period. National genitourinary medicine clinic surveillance data informed key HIV risk assumptions. Pragmatic large-scale implementation scenarios were explored. At 86% effectiveness, PrEP given to 5,000 MSM at 3.3 per 100 person-years annual HIV incidence, assuming risk compensation (20% HIV incidence increase), averted 118 HIV infections over remaining lifetimes and was cost saving. Lower effectiveness (64%) gave an incremental cost-effectiveness ratio of + GBP 23,500 (EUR 32,000) per quality-adjusted life year (QALY) gained. Investment of GBP 26.9 million (EUR 36.6 million) in year-1 breaks even anywhere from year-23 (86% effectiveness) to year-33 (64% effectiveness). PrEP cost-effectiveness was highly sensitive to year-1 HIV incidence, PrEP adherence/effectiveness, and antiretroviral drug costs. There is much uncertainty around HIV incidence in those given PrEP and adherence/effectiveness, especially under programme scale-up. Substantially reduced PrEP drug costs are needed to give the necessary assurance of cost-effectiveness, and for an affordable public health programme of sufficient size

ADOPTING ARTIFICIAL NEURAL NETWORK FOR WEAR INVESTIGATION OF BALL BEARING MATERIALS UNDER PURE SLIDING CONDITION

In the industry, ball bearings are the most widely used machine element. The ball materials may differ in various bearing applications. Wear of the ball and recess after a period of use is the most common cause of ball bearing failure. The present study aims to develop the artificial neural network model for assessing the wear of different ball bearing materials. A wear test method has been followed as suggested by the ASTM-G99 standard. The pin on disc apparatus was selected to conduct numerous trials. L9 array was considered to design the experiments. The factors considered for this study were load, time, and sliding speed. Based on the results obtained, ANN code was proposed to evaluate wear using numerous test parameters. The results obtained from the proposed model are nearly similar to experimental results, which would be evidence for the correctness of the model. The proposed neural network model can be used in numerous applications with given parameters

HIV incidence in men who have sex with men in England and Wales 2001-10: a nationwide population study.

BACKGROUND: Control of HIV transmission could be achievable through an expansion of HIV testing of at-risk populations together with ready access and adherence to antiretroviral therapy. To examine whether increases in testing rates and antiretroviral therapy coverage correspond to the control of HIV transmission, we estimated HIV incidence in men who have sex with men (MSM) in England and Wales since 2001. METHODS: A CD4-staged back-calculation model of HIV incidence was used to disentangle the competing contributions of time-varying rates of diagnosis and HIV incidence to observed HIV diagnoses. Estimated trends in time to diagnosis, incidence, and undiagnosed infection in MSM were interpreted against a backdrop of increased HIV testing rates and antiretroviral-therapy coverage over the period 2001-10. FINDINGS: The observed 3·7 fold expansion in HIV testing in MSM was mirrored by a decline in the estimated mean time-to-diagnosis interval from 4·0 years (95% credible interval [CrI] 3·8-4·2) in 2001 to 3·2 years (2·6-3·8) by the end of 2010. However, neither HIV incidence (2300-2500 annual infections) nor the number of undiagnosed HIV infections (7370, 95% CrI 6990-7800, in 2001, and 7690, 5460-10 580, in 2010) changed throughout the decade, despite an increase in antiretroviral uptake from 69% in 2001 to 80% in 2010. INTERPRETATION: CD4 cell counts at HIV diagnosis are fundamental to the production of robust estimates of incidence based on HIV diagnosis data. Improved frequency and targeting of HIV testing, as well as the introduction of ART at higher CD4 counts than is currently recommended, could begin a decline in HIV transmission among MSM in England and Wales. FUNDING: UK Medical Research Council, UK Health Protection Agency

Healthcare provider and service user perspectives on STI risk reduction interventions for young people and MSM in the UK

Objective Behavioural interventions have been shown to reduce sexual behaviours associated with increased risk of sexually transmitted infections in young people (<25 years) and men who have sex with men (MSM) internationally, but evidence from England is limited. We aimed to explore service provider and user experiences and perspectives on behavioural interventions to reduce sexual behaviour risks, and the use of automated methods to triage individuals to these services. Methods We conducted a sequential mixed methods study with sexual health service providers and users in 2015/2016. Qualitative interviews with providers and service users (heterosexual young people and MSM) in London and Brighton allowed us to explore a range of experiences and expectations. A subsequent national web-survey of service providers measured the feasibility of delivery within existing resources and preferences for intervention attributes. Results We conducted 35 service user (15 heterosexual young people; 20 MSM), and 26 provider interviews, and had 100 web-survey responses. We found considerable heterogeneity in prevention services offered. Service users and providers were broadly supportive of tailoring interventions offered, but service users raised concerns about automated, data-driven triage, particularly around equity and fairness of service delivery. Digital technologies, including social media or apps, were appealing to providers, being less resource intensive. However, one-to-one talking interventions remained popular with both service users and providers, being familiar, trust-worthy, and personal. Key tensions between desirability of interventions and availability of resources to deliver them was acknowledged/recognised by providers and users. Conclusion Overall, behavioural interventions to reduce sexual behaviour risks were viewed favourably by service providers and users, with key considerations including: privacy, personalisation and convenience. However, introducing desirable targeted interventions within heterogeneous sexual health settings will require resources to adapt interventions and research to fully understand the barriers and facilitators to use within routine services

Preparing for PrEP: estimating the size of the population eligible for HIV pre-exposure prophylaxis among men who have sex with men in England.

OBJECTIVES: The size of the population of men who have sex with men (MSM) who may be eligible for HIV pre-exposure prophylaxis (HIV-PrEP) in England remains unknown. To plan for a national PrEP implementation trial, we estimated the number of MSM attending sexual health clinics (SHCs) that may be eligible for HIV-PrEP in England. METHODS: Sexually transmitted infection (STI) surveillance data from 2010 to 2015 from the GUMCAD surveillance system were used to estimate the annual number of HIV-negative MSM who may be eligible for HIV-PrEP in England. Based on national eligibility criteria, we identified HIV-negative MSM attending SHCs with a HIV-negative test in the past year and used diagnosed bacterial STI (past year) in this group as a proxy for condomless sex and eligibility for HIV-PrEP. We estimated HIV incidence per 100 person-years (py) in these groups in 2014. RESULTS: During 2010-2015, the number of HIV-negative MSM attending SHCs with a HIV-negative test in the past year doubled from 14 643 to 29 023, and HIV incidence in this group was 1.9 (95% CI 1.6 to 2.2) per 100 py in 2014. In the same period, the subgroup with a bacterial STI diagnosis (past year), and therefore considered potentially eligible for HIV-PrEP in this analysis, increased from 4365 (30%) to 10 276 (35%). HIV incidence in this subgroup was 3.3 (95% CI 2.7 to 4.0) per 100 py in 2014. CONCLUSIONS: In 2015, approximately 10 000 HIV-negative MSM were considered potentially eligible for HIV-PrEP based on clinic history in GUMCAD. These data were used to inform the initial recruitment target for the PrEP Impact Trial and will inform future evaluations at a population level

Adolescent transport and unintentional injuries: a systematic analysis using the Global Burden of Disease Study 2019

Background: Globally, transport and unintentional injuries persist as leading preventable causes of mortality and morbidity for adolescents. We sought to report comprehensive trends in injury-related mortality and morbidity for adolescents aged 10–24 years during the past three decades. Methods: Using the Global Burden of Disease, Injuries, and Risk Factors 2019 Study, we analysed mortality and disability-adjusted life-years (DALYs) attributed to transport and unintentional injuries for adolescents in 204 countries. Burden is reported in absolute numbers and age-standardised rates per 100 000 population by sex, age group (10–14, 15–19, and 20–24 years), and sociodemographic index (SDI) with 95% uncertainty intervals (UIs). We report percentage changes in deaths and DALYs between 1990 and 2019. Findings: In 2019, 369 061 deaths (of which 214 337 [58%] were transport related) and 31·1 million DALYs (of which 16·2 million [52%] were transport related) among adolescents aged 10–24 years were caused by transport and unintentional injuries combined. If compared with other causes, transport and unintentional injuries combined accounted for 25% of deaths and 14% of DALYs in 2019, and showed little improvement from 1990 when such injuries accounted for 26% of adolescent deaths and 17% of adolescent DALYs. Throughout adolescence, transport and unintentional injury fatality rates increased by age group. The unintentional injury burden was higher among males than females for all injury types, except for injuries related to fire, heat, and hot substances, or to adverse effects of medical treatment. From 1990 to 2019, global mortality rates declined by 34·4% (from 17·5 to 11·5 per 100 000) for transport injuries, and by 47·7% (from 15·9 to 8·3 per 100 000) for unintentional injuries. However, in low-SDI nations the absolute number of deaths increased (by 80·5% to 42 774 for transport injuries and by 39·4% to 31 961 for unintentional injuries). In the high-SDI quintile in 2010–19, the rate per 100 000 of transport injury DALYs was reduced by 16·7%, from 838 in 2010 to 699 in 2019. This was a substantially slower pace of reduction compared with the 48·5% reduction between 1990 and 2010, from 1626 per 100 000 in 1990 to 838 per 100 000 in 2010. Between 2010 and 2019, the rate of unintentional injury DALYs per 100 000 also remained largely unchanged in high-SDI countries (555 in 2010 vs 554 in 2019; 0·2% reduction). The number and rate of adolescent deaths and DALYs owing to environmental heat and cold exposure increased for the high-SDI quintile during 2010–19. Interpretation: As other causes of mortality are addressed, inadequate progress in reducing transport and unintentional injury mortality as a proportion of adolescent deaths becomes apparent. The relative shift in the burden of injury from high-SDI countries to low and low–middle-SDI countries necessitates focused action, including global donor, government, and industry investment in injury prevention. The persisting burden of DALYs related to transport and unintentional injuries indicates a need to prioritise innovative measures for the primary prevention of adolescent injury. Funding: Bill &amp; Melinda Gates Foundation