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Abstract Background Structural interventions are endorsed to enhance biomedical and behavioural HIV prevention programmes for adolescents. Aiming to inform future interventions, we evaluated longitudinal associations between six protective factors that link closely to existing structural HIV prevention interventions, and five sexual risk behaviours for HIV transmission in a cohort of adolescents in South Africa. Methods We used three rounds of data between 2014–2018 on 1046 adolescents living with HIV and 473 age-matched community peers in South Africa’s Eastern Cape (Observations = 4402). We estimated sex-specific associations between six time-varying protective factors − number of social grants, education enrolment, days with enough food, caregiver supervision, positive caregiving, and adolescent-caregiver communication; and five HIV risk behaviours − multiple sexual partners, transactional sex, age-disparate sex, condomless sex, and sex on substances. HIV risk behaviours were analysed separately in multivariable random effects within-between logistic regression models that accounted for correlation of repeated observations on the same individual. We calculated prevalence ratios (PR), contrasting adjusted probabilities of HIV risk behaviours at ‘No’ and ‘Yes’ for education enrolment, and average and maximum values for the other five protective factors. Results The sample mean age was 15.29 (SD: 3.23) years and 58% were girls. Among girls, within-individuals, increases from mean to maximum scores in positive caregiving were associated with lower probability of transactional sex (PR = 0.79; 95%CI = 0.67–0.91); in caregiver supervision were associated with lower probability of transactional sex (PR = 0.75; 95%CI = 0.66–0.84), and age-disparate sex (PR = 0.84; 95%CI = 0.73–0.95); in adolescent-caregiver communication were associated with higher probability of transactional sex (PR = 1.70; 95%CI = 1.08–2.32); and in days with enough food at home were associated with lower probability of multiple sexual partners (PR = 0.89; 95%CI = 0.81–0.97), and transactional sex (PR = 0.82; 95%CI = 0.72–0.92). Change from non-enrolment in education to enrolment was associated with lower probability of age-disparate sex (PR = 0.49; 95%CI = 0.26–0.73). Between-individuals, relative to mean caregiver supervision scores, maximum scores were associated with lower probability of multiple sexual partners (PR = 0.59; 95%CI = 0.46–0.72), condomless sex (PR = 0.80; 95%CI = 0.69–0.91), and sex on substances (PR = 0.42; 95%CI = 0.26–0.59); and relative to non-enrolment, education enrolment was associated with lower probability of condomless sex (PR = 0.59; 95%CI = 0.39–0.78). Among boys, within-individuals, increases from mean to maximum scores in positive caregiving were associated with lower probability of transactional sex (PR = 0.77; 95%CI = 0.59–0.96), and higher probability of condomless sex (PR = 1.26; 95%CI = 1.08–1.43); in caregiver supervision were associated with lower probability of multiple sexual partners (PR = 0.73; 95%CI = 0.64–0.82), transactional sex (PR = 0.63; 95%CI = 0.50–0.76), age-disparate sex (PR = 0.67; 95%CI = 0.49–0.85), and sex on substances (PR = 0.61; 95%CI = 0.45–0.78), and in days with enough food at home were associated with lower probability of transactional sex (PR = 0.91; 95%CI = 0.84–0.98). Conclusion Effective structural interventions to improve food security and education enrolment among adolescent girls, and positive and supervisory caregiving among adolescent girls and boys are likely to translate into crucial reductions in sexual risk behaviours linked to HIV transmission in this population.

Abstract Background Accelerating declines in tuberculosis (TB) incidence is paramount for achieving global goals set for 2030 by the Sustainable Development Goals and the End TB Strategy. The aim of this study was to identify key country-level social determinants of national TB incidence trends. Methods This longitudinal ecological study used country-level data extracted from online databases from the period 2005–2015. We used multivariable Poisson regression models allowing for distinct within- and between-country effects to estimate associations between national TB incidence rates and 13 social determinants of health. The analysis was stratified by country income status. Results The study sample included 48 low- and lower-middle-income countries (LLMICs) and 68 high- and upper-middle income countries (HUMICs), with a total of 528 and 748 observations between 2005–2015, respectively. National TB incidence rates declined in 108/116 countries between 2005–2015, with an average drop of 12.95% in LLMICs and 14.09% in HUMICs. Between LLMICs, higher Human Development Index (HDI), social protection spending, TB case detection, and TB treatment success were associated with lower TB incidence. Higher prevalence of HIV/AIDS was associated with higher TB incidence. Within LLMICs, increases in HDI over time were associated with lower TB incidence rates. Between HUMICs, higher HDI, health spending, and diabetes prevalence were associated with lower TB incidence, whereas higher prevalence of HIV/AIDS and alcohol-use were associated with higher TB incidence. Within HUMICs, increases in HIV/AIDS and diabetes prevalence over time were associated with higher TB incidence. Conclusions In LLMICs, TB incidence rates remain highest in countries with low human development, social protection spending and TB programme performance, and high rates of HIV/AIDS. Strengthening human development is likely to accelerate declines in TB incidence. In HUMICs, TB incidence rates remain highest in countries with low human development, health spending and diabetes prevalence, and high rates of HIV/AIDS and alcohol use. Here, slowing rising rates of HIV/AIDS and diabetes is likely to accelerate declines in TB incidence.

Abstract Background The World Health Organization prioritises a more holistic global response to end the tuberculosis (TB) epidemic by 2030. Based on experiences in the HIV response, social protection, and in particular cash transfers, show promise for contributing to this. Currently, individual-level evidence for the potential of cash transfers to prevent TB by addressing the structural social determinants of disease is lacking. To identify priority actions for the TB research agenda, we appraised efforts by the HIV response to establish the role of cash transfers in preventing HIV infection. Main body The HIV response has evaluated the effects of cash transfers on risky sexual behaviours and HIV incidence. Work has also evaluated the added effects of supplementing cash transfers with psychosocial support. The HIV response has focused research on populations with disproportionate HIV risk, and used a mix of explanatory evaluations, which use ideal conditions, and pragmatic evaluations, which use operational conditions, to generate evidence that is both causally valid and applicable to the real world. It has always collaborated with multiple stakeholders in funding and evaluating projects. Learning from the HIV response, priority actions for the TB response should be to investigate the effect of cash transfers on intermediary social determinants of active TB disease, and TB incidence, as well as the added effects of supplementing cash transfers with psychosocial support. Work should be focused on key groups in high burden settings, and look to build a combination of explanatory and pragmatic evidence to inform policy decisions in this field. To achieve this, there is an urgent need to facilitate collaborations between groups interested in evaluating the impact of cash transfers on TB risk. Conclusions The HIV response highlights several priority actions necessary for the TB response to establish the potential of cash transfers to prevent TB by addresing the structural social determinants of disease.