SACEMA has been very active in refining the use of laboratory tests for identifying recent infection (in particular of HIV) for the purpose of estimating disease incidence. We have just published a conceptual analysis of the notion of ‘test optimisation’ in a surveillance context, which should help clarify some persistent confusion that has hindered discourse in this area for years.
Eastern and southern Africa remains the region most affected by the HIV epidemic in the world and accounts for more than 50% of the global burden of HIV. Significant progress has been made in recent years in the response to the epidemic in the region: new HIV infections and AIDS deaths have fallen while prevention and treatment services for HIV have increased substantially. While several challenges still remain, there is renewed optimism that the elimination of HIV and AIDS is not an impossible goal.
Using a catalytic model no significant reduction of HIV incidence was found despite increasing ART coverage.
SACEMA presented modelling work on e.g. incidence and prevalence of HIV at the two recent HIV and AIDS conference.
The headline-grabber at the 20th Conference for Retroviruses and Opportunistic Infections (CROI) was the ‘functional cure’ of an HIV-infected child. A key success of the ‘Mississippi miracle’ is that no latent reservoir of replication-competent HIV developed in the infant. The study of latent reservoirs, and prospects for eliminating these through treatment, in adults and infants, was the topic of many sessions. Apart from the laboratory science, a number of results from studies and modelling exercises were presented, assessing a number of risk factors and interventions for various conditions. Of particular relevance to the work of SACEMA is the topic of HIV incidence estimation. CEPHIA hosted a satellite session, focussed on the first independent assessments of incidence assays for HIV incidence estimation in cross-sectional studies.
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.
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.
In contrast with the other regions, HIV infection in sub-Saharan Africa (SSA) is prevalent in the general population with low levels of reported sexual risk behaviours. SSA bears also the highest burden of infectious diseases other than HIV such as malaria, tuberculosis, herpes simplex virus type 2, among other infectious diseases. The drivers of the Read More
Accurate HIV incidence estimates are essential for monitoring the HIV epidemic, determining public health priorities and assessing the impact of interventions. There are many approaches to estimating incidence. The “gold standard” approach is through observational studies, in which subjects are periodically monitored for HIV infection. However, such studies are time consuming, expensive and may provide Read More
At the end of September 2012 an article was published in AIDS with the title Modelling the global competing risks of a potential interaction between injectable hormonal contraception and HIV risk. As some, but not all, observational studies have suggested an increase in risk of HIV acquisition for women using injectable hormonal contraception (IHC), this Read More