Spatial variability in HIV prevalence declines in several countries in sub-Saharan Africa

AbstractEvidence suggests substantial declines in HIV prevalence in parts of sub-Saharan Africa. However, the observed aggregate declines at the national level may obscure local variations in the temporal dynamics of the infection. Using spatial scan statistics, we identified marked spatial variability in the within-country declines in HIV prevalence in Tanzania, Malawi, Kenya, and Zimbabwe. Our study suggests that the declines in the national HIV prevalence in some of the SSA countries may not be representative of downward trends in prevalence in areas of high HIV prevalence, as much as the result of sharp declines in prevalence in areas of already low HIV prevalence. Our findings provide insights for resource allocation and HIV prevention interventions in these countries

О перспективах рынка станкостроения с позиций анализа мировых тенденций, концепции жизненного цикла оборудования и CALS-технологий

В статье рассматриваются существующие методики выбора и проектирования нового оборудования с позиций анализа наиболее эффективных видах обработки, проводится анализ недостатков "классического" подхода к выбору оборудования. На основании CALS-технологий, принципа агрегатирования и паспортизации оборудования предлагается новая модель проектирования оборудования, позволяющая продлить жизненный цикл станков, уменьшить стоимость и сроки проектирования и изготовления оборудования.This article reviews the existing methods of choice and design of new equipment from the standpoint of analyzing the most effective forms of treatment, an analysis of the shortcomings of "classical" approach to the choice of equipment. Based on CALS-technologies, the principle of aggregation and certification of equipment, a new model for the design of equipment are proposed. This model allows to extend the life cycle of machines, reduce the cost and terms of designing and manufacturing equipment

External infections contribute minimally to HIV incidence among HIV sero-discordant couples in sub-Saharan Africa.

OBJECTIVE: Recent randomised clinical trials among stable HIV sero-discordant couples (SDCs) in sub-Saharan Africa (SSA) have reported that about 20-30% of new HIV infections are acquired from external sexual partners, rather than transmitted from the infected to the uninfected partner within the couple. The aim of this study is to examine whether, and to what extent, these findings are generalisable to SDCs in the wider population in SSA. METHODS: A mathematical model was constructed to calculate the fraction of new HIV-1 infections among SDCs that are due to sources external to the couple. The model was parameterised using empirical and population-based data for 20 countries in SSA. Uncertainty and sensitivity analyses were also conducted. RESULTS: The contribution of external infections among SDCs was generally modest, but it varied widely across SSA. In low HIV prevalence countries (≤ 3.0%), it ranged from 0.6-2.9%. In intermediate prevalence countries (3.0-18.0%), it ranged from 4.9-11.7%. In Swaziland and Lesotho, the world's most-intense epidemics, sizable levels of 27.9% and 27.3% were found, respectively. CONCLUSIONS: In most countries in SSA, nearly all HIV acquisitions by the uninfected partners in SDCs appear to be due to transmissions from the HIV infected partners in the SDCs. The contribution of externally acquired infections varies with HIV population prevalence, but rarely exceeds 10% in the majority of countries. Only in hyperendemic HIV epidemics the contribution of external infections is substantial and may reach the levels reported in recent randomised clinical trials involving SDCs

The emerging face of the HIV epidemic in the Middle East and North Africa.

PURPOSE OF REVIEW: A volume of quality HIV data has materialized recently in the Middle East and North Africa (MENA). This review provides a thematic narrative of the patterns of HIV infection transmission in this region in light of these data. RECENT FINDINGS: Tens of integrated bio-behavioral surveillance surveys among hard-to-reach key populations at higher risk have been conducted in MENA in the recent years. Many of the studies reported appreciable and growing HIV prevalence. A few studies found alarming prevalence of as much as 87.2% HIV prevalence among people who inject drugs in Tripoli, Libya. The discovery of these hitherto hidden epidemics was unsettling to some authorities after years in which the importance of a focus on HIV prevention among key populations was not recognized. SUMMARY: The new data from MENA indicate growing HIV epidemics among key populations across the region. There is heterogeneity, however, as to which key populations are affected and in what proportions in different countries. In a few countries, HIV appears to affect only one key population and often there is substantial geographical heterogeneity in HIV transmission. Data are indicative of a growing HIV disease burden in this part of the globe, in contrast with the declining epidemics in most other regions

Epidemiological impact of public health interventions against diabetes in Qatar: mathematical modeling analyses

AimsTo predict the epidemiological impact of specific, and primarily structural public health interventions that address lifestyle, dietary, and commuting behaviors of Qataris as well as subsidies and legislation to reduce type 2 diabetes mellitus (T2DM) burden among Qataris.MethodsA deterministic population-based mathematical model was used to investigate the impact of public health interventions on the epidemiology of T2DM among Qataris aged 20–79 years, which is the age range typically used by the International Diabetes Federation for adults. The study evaluated the impact of interventions up to 2050, a three-decade time horizon, to allow for the long-term effects of different types of interventions to materialize. The impact of each intervention was evaluated by comparing the predicted T2DM incidence and prevalence with the intervention to a counterfactual scenario without intervention. The model was parameterized using representative data and stratified by sex, age, T2DM risk factors, T2DM status, and intervention status.ResultsAll intervention scenarios had an appreciable impact on reducing T2DM incidence and prevalence. A lifestyle management intervention approach, specifically applied to those who are categorized as obese and ≥35 years old, averted 9.5% of new T2DM cases by 2050. An active commuting intervention approach, specifically increasing cycling and walking, averted 8.5% of new T2DM cases by 2050. Enhancing consumption of healthy diets including fruits and vegetables, specifically a workplace intervention involving dietary modifications and an educational intervention, averted 23.2% of new T2DM cases by 2050. A subsidy and legislative intervention approach, implementing subsidies on fruits and vegetables and taxation on sugar-sweetened beverages, averted 7.4% of new T2DM cases by 2050. A least to most optimistic combination of interventions averted 22.8–46.9% of new T2DM cases by 2050, respectively.ConclusionsImplementing a combination of individual-level and structural public health interventions is critical to prevent T2DM onset and to slow the growing T2DM epidemic in Qatar

Vertical transmission of hepatitis C virus: systematic review and meta-analysis.

BACKGROUND: We conducted a systematic review of estimates of hepatitis C virus (HCV) vertical transmission risk to update current estimates published more than a decade ago. METHODS: PubMed and Embase were searched and 109 articles were included. Pooled estimates of risk were generated for children born to HCV antibody-positive and viremic women, aged ≥18 months, separately by maternal human immunodeficiency virus (HIV) coinfection. RESULTS: Meta-analysis of the risk of vertical HCV infection to children of HCV antibody-positive and RNA-positive women was 5.8% (95% confidence interval [CI], 4.2%-7.8%) for children of HIV-negative women and 10.8% (95% CI, 7.6%-15.2%) for children of HIV-positive women. The adjusted meta-regression model explained 51% of the between-study variation in the 25 included risk estimates. Maternal HIV coinfection was the most important determinant of vertical transmission risk (adjusted odds ratio, 2.56 [95% CI, 1.50-4.43]). Additional methodological (follow-up rate and definition of infection in children) and risk factors independently predicted HCV infection and need to be captured and reported by future studies of vertical transmission. Studies assessing the contribution of nonvertical exposures in early childhood to HCV prevalence among children at risk of vertical transmission are needed. CONCLUSIONS: More than 1 in every 20 children delivered by HCV chronically infected women are infected, highlighting that vertical transmission likely constitutes the primary transmission route among children. These updated estimates are a basis for decision making in prioritization of research into risk-reducing measures, and inform case management in clinical settings, especially for HIV-positive women in reproductive age

Dynamics of non-cohabiting sex partnering in sub-Saharan Africa: a modelling study with implications for HIV transmission.

OBJECTIVE: To develop an analytical understanding of non-cohabiting sex partnering in sub-Saharan Africa (SSA) using nationally representative sexual behaviour data. METHOD: A non-homogenous Poisson stochastic process model was used to describe the dynamics of non-cohabiting sex. The model was applied to 25 countries in SSA and was fitted to Demographic and Health Survey data. The country-specific mean values and variances of the distributions of number of non-cohabiting partners were estimated. RESULTS: The model yielded overall robust fits to the empirical distributions stratified by marital status and sex. The median across all country-specific mean values was highest for unmarried men at 0.574 non-cohabiting partners over the last 12 months, followed by that of unmarried women at 0.337, married men at 0.192 and married women at 0.038. The median of variances was highest for unmarried men at 0.127, followed by married men at 0.057, unmarried women at 0.003 and married women at 0.000. The largest variability in mean values across countries was for unmarried men (0.103-1.206), and the largest variability in variances was among unmarried women (0.000-1.994). CONCLUSIONS: Non-cohabiting sex appears to be a random 'opportunistic' phenomenon linked to situations that may facilitate it. The mean values and variances of number of partners in SSA show wide variation by country, marital status and sex. Unmarried individuals have larger mean values than their married counterparts, and men have larger mean values than women. Unmarried individuals appear to play a disproportionate role in driving heterogeneity in sexual networks and possibly epidemiology of sexually transmitted infections

Epidemiology of herpes simplex virus type 2 in sub-Saharan Africa:systematic review, meta-analyses, and meta-regressions

Background: Herpes simplex virus type 2 (HSV-2) infection is a prevalent, sexually transmitted infection with a sizable disease burden that is highest in sub-Saharan Africa. This study aimed to characterize HSV-2 epidemiology in this region. Methods: Cochrane and PRISMA guidelines were followed to systematically review, synthesize, and report HSV-2 related findings up to August 23, 2020. Meta-analyses and meta-regressions were conducted. Findings: From 218 relevant publications, 451 overall outcome measures and 869 stratified measures were extracted. Pooled incidence rates ranged between 2.4–19.4 per 100 person-years across populations. Pooled seroprevalence was lowest at 37.3% (95% confidence interval (CI): 34.9–39.7%) in general populations and high in female sex workers and HIV-positive individuals at 62.5% (95% CI: 54.8–70.0%) and 71.3% (95% CI: 66.5–75.9%), respectively. In general populations, pooled seroprevalence increased steadily with age. Compared to women, men had a lower seroprevalence with an adjusted risk ratio (ARR) of 0.61 (95% CI: 0.56–0.67). Seroprevalence has decreased in recent decades with an ARR of 0.98 (95% CI: 0.97–0.99) per year. Seroprevalence was highest in Eastern and Southern Africa. Pooled HSV-2 proportion in genital ulcer disease was 50.7% (95% CI: 44.7–56.8%) and in genital herpes it was 97.3% (95% CI: 84.4–100%). Interpretation: Seroprevalence is declining by 2% per year, but a third of the population is infected. Age and geography play profound roles in HSV-2 epidemiology. Temporal declines and geographic distribution of HSV-2 seroprevalence mirror that of HIV prevalence, suggesting sexual risk behavior has been declining for three decades. HSV-2 is the etiological cause of half of genital ulcer disease and nearly all genital herpes cases with limited role for HSV-1. Funding: This work was supported by pilot funding from the Biomedical Research Program at Weill Cornell Medicine in Qatar and by the Qatar National Research Fund [NPRP 9–040–3–008]

Herpes simplex virus type 1 epidemiology in Africa: Systematic review, meta-analyses, and meta-regressions.

OBJECTIVE: To assess herpes simplex virus type 1 (HSV-1) epidemiology in Africa. METHODS: This systematic review was conducted per the Cochrane Collaboration guidelines. Findings were reported following the PRISMA guidelines. Research questions were addressed using random-effects meta-analyses and meta-regressions. RESULTS: Forty-three overall (and 69 stratified) HSV-1 seroprevalence measures, and 18 and eight proportions of HSV-1 viral detection in genital ulcer disease (GUD) and in genital herpes, respectively, were extracted from 37 reports. Pooled mean seroprevalence was 67.1% (95% confidence interval (CI): 54.7-78.5%) in children, and 96.2% (95% CI: 95.0-97.3%) in adults. Across age groups, pooled mean was 44.4% (95% CI: 29.9-59.3%) in ≤5 years-old, 85.6% (95% CI: 81.0-89.6%) in 6-15 years-old, 93.3% (95% CI: 89.2-96.6%) in 16-25 years-old, and 93.8% (95% CI: 84.6-99.4%) in >25 years-old. Age explained 78.8% of seroprevalence variation. Pooled mean proportion of HSV-1 detection was 0.4% (95% CI: 0.0-1.5%) in GUD, and 1.2% (95% CI: 0.0-4.0%) in genital herpes. CONCLUSIONS: HSV-1 is universally prevalent in Africa, at higher levels than other regions, with no evidence for declines in seroprevalence in recent decades. Nearly every person acquires the infection in childhood through oral-to-oral transmission, before sexual debut. Sexual oral-to-genital and genital-to-genital transmission appear very limited

Estimation of hepatitis C virus infections resulting from vertical transmission in Egypt.

UNLABELLED: Despite having the highest hepatitis C virus (HCV) prevalence in the world, the ongoing level of HCV incidence in Egypt and its drivers are poorly understood. Whereas HCV mother-to-child infection is a well-established transmission route, there are no estimates of HCV infections resulting from vertical transmission for any country, including Egypt. The aim of this study was to estimate the absolute number of new HCV infections resulting from vertical transmission in Egypt. We developed a conceptual framework of HCV vertical transmission, expressed in terms of a mathematical model and based on maternal HCV antibody and viremia. The mathematical model estimated the number of HCV vertical infections nationally and for six subnational areas. Applying two vertical transmission risk estimates to the 2008 Egyptian birth cohort, we estimated that between 3,080 and 5,167 HCV infections resulted from vertical transmission among children born in 2008. HCV vertical transmission may account for half of incident cases in the <5-year age group. Disproportionately higher proportions of vertical infections were estimated in Lower Rural and Upper Rural subnational areas. This geographical clustering was a result of higher-area-level HCV prevalence among women and higher fertility rates. CONCLUSION: Vertical transmission is one of the primary HCV infection routes among children<5 years in Egypt. The absolute number of vertical transmissions and the young age at infection highlight a public health concern. These findings also emphasize the need to quantify the relative contributions of other transmission routes to HCV incidence in Egypt