Measuring and modelling concurrency

This article explores three critical topics discussed in the recent debate over concurrency (overlapping sexual partnerships): measurement of the prevalence of concurrency, mathematical modelling of concurrency and HIV epidemic dynamics, and measuring the correlation between HIV and concurrency. The focus of the article is the concurrency hypothesis – the proposition that presumed high prevalence of concurrency explains sub-Saharan Africa's exceptionally high HIV prevalence. Recent surveys using improved questionnaire design show reported concurrency ranging from 0.8% to 7.6% in the region. Even after adjusting for plausible levels of reporting errors, appropriately parameterized sexual network models of HIV epidemics do not generate sustainable epidemic trajectories (avoid epidemic extinction) at levels of concurrency found in recent surveys in sub-Saharan Africa. Efforts to support the concurrency hypothesis with a statistical correlation between HIV incidence and concurrency prevalence are not yet successful. Two decades of efforts to find evidence in support of the concurrency hypothesis have failed to build a convincing case

Exploring the demand‐side factors associated with the use of implants in Kenya

We explore the demand‐side factors associated with the use of implants in Kenya given the notable rapid increase in uptake of the method in the country. Data are from a longitudinal study conducted among married or cohabiting women aged 15–39 years at the time of recruitment in one rural (2,424 women) and one urban (2,812 women) site. Analysis entails descriptive statistics and estimation of multivariate logistic regression models. The results show that the key demand‐side factors associated with the use of implants were low discontinuation of the method compared with alternatives and strong motivation on the part of the women for long‐term spacing of births. However, implants had no perceived advantages over the main alternative methods in terms of beliefs about possible damage to health or unpleasant side effects or in terms of satisfaction with use. The findings suggest that addressing concerns about safety for long‐term use and for health may increase demand for implants in particular and long‐acting reversible contraceptives in general in the study settings or in similar contexts, especially among women who desire long‐term spacing of births