November 2011

Published on November 28, 2011 by

Editorial: Looking back at 2011 and into the future

The year is rushing to a close. World Aids Day is around the corner, and from our vantage point at SACEMA, 2011 is likely to be remembered as the year in which the concept of Treatment as Prevention (TasP) stopped being controversial. Few now seriously express doubt that effective ARV treatment cuts transmission, and debate has moved on to grapple with the questions of the extent, and over what time scale, this can translate into ‘game changing’ or ‘paradigm shifting’ scenarios.

Published on November 28, 2011 by

Testing for Recent Infection to Estimate HIV Incidence from Single Cross-Sectional Surveys

There are a number of approaches for estimating HIV incidence, with varying tractability, complexity and limitations. In recent years, there has been considerable interest in estimating HIV incidence from single cross-sectional surveys testing for ‘recent infection’ through laboratory-measured host or viral biomarkers. In a survey, the sizes of the HIV-negative, ‘recently infected’ and ‘non-recently infected’ populations can be measured, and incidence estimated using knowledge of the dynamics of the ‘recent infection’ biomarker. However, two key obstacles to cross-sectional biomarker-based incidence surveillance remain: the lack of standardisation of terminology and methodology, and poor characteristics, and characterisation, of currently available tests.

Published on November 28, 2011 by

An investigation into the statistical properties of TB episodes in a South African community with a high HIV prevalence

There are few students in epidemiological modeling and analysis who can resist the temptation to fit a theoretical disease model to real epidemic data. A recent DNA fingerprinting project from Masiphumelele, a township near Cape Town, offered such a temptation. The result is a short journey into the world of statistically rare events, in this case brought about by the relatively small size of Masiphumele and by the slow reactivation rates of TB.

Published on November 28, 2011 by

Joint Mapping Modelling for Multiple Health Problems in South Africa

Disease mapping models are used in spatial epidemiologic studies to investigate the causes and distributions of diseases. Most of the studies looking at mapping of health problems in the Sub-Saharan African region have concentrated on using univariate spatial models. However, there is a need to use and apply joint mapping models to measure co-morbidities of common illnesses in the region. This article aims to show the utility of joint mapping models in estimating co-morbidities in two important health problems in South Africa: HIV and Syphilis, and vascular diseases.

Short item Published on November 28, 2011

Modelling the potential impact of an antiretroviral microbicide gel on the HIV epidemic in South Africa

One of the major obstacles to preventing HIV-transmission has been the lack of an effective, female controlled method of prevention. Now, for the first time, a vaginal microbicide has been shown to reduce the risk of infection in women. CAPRISA 004 was a randomized placebo-controlled trial to assess the effectiveness and safety of a 1% Read More

Short item Published on November 28, 2011

Sexual connectedness and HIV infection in disadvantaged communities around Cape Town

The sexual network structure and the distribution of HIV remain inadequately understood, especially with regard to the role of concurrency and age disparity in relationships, and how these network characteristics correlate with each other and other risk factors. Additionally, sources of bias, such as social desirability bias and inaccurate recall, make it difficult to obtain Read More

Short item Published on November 28, 2011

HIV Disease Progression in South Africa using Multistate Markov Models

An understanding of HIV progression and factors that influence disease progression can have great value in the development of new treatment strategies. Although Sub-Saharan Africa is noted for its high HIV prevalence there is an absence of research on HIV progression and factors affecting it. In patients who do not receive antiretroviral therapy, a decreasing Read More