SACEMA Quarterly

Update on epidemiology for health professionals and policy makers.
SACEMA Quarterly is an online magazine produced by SACEMA. The aim is to provide articles reviewing developments in quantitative epidemiology. The intention of the magazine is to present this work in a way that it is accessible to the interested health professional and policy-maker.
Monday 20th of May 2013
Wim Delva, Cari van Schalkwyk

Editorial: Statistical and epidemiological modelling towards Maximizing ART for Better Health and Zero New HIV Infections

The contributions in this issue of the SACEMA Quarterly focus on different aspects related to TB and incidence of HIV. This editorial focuses on HIV treatment as prevention by presenting the MaxART project (Maximizing ART for Better Health and Zero New HIV Infections). This project pursues the dream of reaching all people in Swaziland who are in need of treatment with an ultimate goal of preparing the country for the possibility of ending the HIV epidemic. SACEMA is one of the members of the MaxART consortium and is involved in various modelling and analysis activities that are presented here.

→ continue reading
Florian M. Marx

Sputum smear-positive tuberculosis among previously treated individuals in the Western Cape Province, South Africa

A considerable share of South Africa’s tuberculosis burden affects those people who have previously been treated for tuberculosis – many of them successfully. In a retrospective cohort study that was conducted using tuberculosis treatment register data from two communities in suburban Cape Town, it was found that the hazard rate of re-treatment for smear-positive tuberculosis was between 3- and 5.26-times higher in tuberculosis cases who had defaulted from treatment compared to successfully treated cases. But although the rate of re-treatment was substantially higher among defaulters, cases after treatment success account for the vast majority of smear-positive re-treatment cases due to the fact that far more tuberculosis cases were successfully treated than had defaulted.

→ continue reading
Rod Bennett, Brian Williams

Oscillating Migration Driving HIV and TB in sub-Saharan Africa

The system of oscillating labour migration, especially to the gold mines in South Africa, has helped to spread TB throughout southern Africa and it now helps to spread HIV. This article illustrates this link by reporting on a study on the impact of migrant labour in the mines in South Africa on the burden of HIV and TB in Mozambique. Furthermore, modelling studies have shown that even if we maintain the same patterns of sexual behaviour the presence or absence of migration can lead to dramatically different outcomes. Unless a comprehensive and fully coordinated multi-country and multi-sectoral programme is implemented and followed through, we may find that the HIV and TB epidemics are far more resilient than consideration of the epidemics in each country suggests.

→ continue reading
Cari van Schalkwyk

Different ways to estimate the mean duration of “recent HIV infection” as measured by the BED assay

Robust affordable means for estimating HIV incidence at the population level continue to be elusive and much desired. As resources are invested in developing more appropriate tests for recent infection, the methods for evaluating and optimising the performance of candidate tests need to be further refined. We have recently explored a range of statistical methods for estimating the mean duration of recent infection (MDRI) by investigating a data set from Harare, Zimbabwe. We investigated whether there is an optimum way of estimating the mean recency duration for this dataset. We also ask how estimates of the mean recency duration and incidence are affected by our choice of cut-off and whether these effects differ with our choice of estimation method.

→ continue reading
Logo SACEMA Logo Stellenbosch University