Implementing HIV Prevention in Sub-Saharan Africa: A Systematic Review of Interventions Targeting Systems, Communities, and Individuals.

HIV remains a threat to global public health, disproportionately affecting countries across Sub-Saharan Africa. Although treatment and access to care have improved, prevention remains critical to ending new HIV infections by 2030. A variety of prevention strategies exist, yet their effectiveness is difficult to measure and variable due to the nature of the interventions and vulnerability of the intervention during implementation. This systematic review of 51 studies synthesizes data on the implementation and evaluation of evidence-based HIV prevention interventions across Sub-Saharan Africa. Studies were included if they occurred between January 1, 2008, and December 31, 2019, inclusive in Sub-Saharan Africa, were written in English, implemented an HIV prevention intervention in the field, and had reportable results. Using a modified social-ecological model for HIV prevention, we divided studies into three categories: interventions targeting health systems (n = 16), communities (n = 8), and individuals (n = 27). Across all categories, the data emphasized preventing mother-to-child transmission (PMTCT), medical interventions, and psychosocial interventions. The most successful programs bundled several interventions that were integrated into the health system. There is a notable lack of interventions targeting key populations and there are significant rates of loss to follow up (LTFU) across many studies. This review provides insight into the prioritization of evidence-based HIV prevention interventions across Sub-Saharan Africa.

Corpus callosum axon diameter relates to cognitive impairment in multiple sclerosis.

OBJECTIVE: To evaluate alterations in apparent axon diameter and axon density obtained by high-gradient diffusion MRI in the corpus callosum of MS patients and the relationship of these advanced diffusion MRI metrics to neurologic disability and cognitive impairment in MS. METHODS: Thirty people with MS (23 relapsing-remitting MS [RRMS], 7 progressive MS [PMS]) and 23 healthy controls were scanned on a human 3-tesla (3T) MRI scanner equipped with 300 mT/m maximum gradient strength using a comprehensive multishell diffusion MRI protocol. Data were fitted to a three-compartment geometric model of white matter to estimate apparent axon diameter and axon density in the midline corpus callosum. Neurologic disability and cognitive function were measured using the Expanded Disability Status Scale (EDSS), Multiple Sclerosis Functional Composite (MSFC), and Minimal Assessment of Cognitive Function in MS battery. RESULTS: Apparent axon diameter was significantly larger and axon density reduced in the normal-appearing corpus callosum (NACC) of MS patients compared to healthy controls, with similar trends seen in PMS compared to RRMS. Larger apparent axon diameter in the NACC of MS patients correlated with greater disability as measured by the EDSS (r = 0.555, P = 0.007) and poorer performance on the Symbol Digits Modalities Test (r = -0.593, P = 0.008) and Brief Visuospatial Memory Test-Revised (r = -0.632, P < 0.01), tests of interhemispheric processing speed and new learning and memory, respectively. INTERPRETATION: Apparent axon diameter in the corpus callosum obtained from high-gradient diffusion MRI is a potential imaging biomarker that may be used to understand the development and progression of cognitive impairment in MS.