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April 2003 Public Health HIV/AIDS Journal Club
Judith King. HIVAN Media Office
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Two presentations were featured at the April 2003 HIV/AIDS Public Health Journal Club held at the University of KwaZulu-Natal's Nelson R Mandela School of Medicine: "Reviewing the HSRC Report on HIV" presented by Professor Jerry Coovadia, followed by "Spinal TB in the era of HIV - clinical and basic science investigations" presented by Dr Suresh Kumar of the School's Department of Orthopaedic Surgery.
Based on saliva testing of 8 428 people from households throughout South Africa, the Human Sciences Research Council's survey is one of the largest studies of its kind and the first nationally representative study of HIV prevalence in the population aged two years and older. It also contains relative data from other developing countries and purports to include rural and urban homesteads in their correct proportions.
Professor Coovadia, who holds the Victor Daitz Chair of HIV/AIDS Research and is Biomedical Director of HIVAN, took the audience through the key findings of the survey, with a particular focus on those results of importance to public health practitioners, and on some of the limitations of the study.
The report indicates that 11.4% of South Africa's population is HIV-positive. The initial sample covered 40 450 participants but this figure was reduced to 9 263 by the refusal of many to be interviewed and tested, and was further reduced by the exclusion of "special institutions" such as hospitals, universities and prisons.
Professor Coovadia noted that the finding of 5,6% of South African children being HIV-positive covered a very broad age range of 2 to 14 years, which was problematic in that no speculations could be made as to the reasons for HIV transmission amongst this sample. It appeared that the provinces of KwaZulu-Natal, Gauteng and the Western Cape had been over-represented, as had certain race groups.
The report confirms that age is a risk factor in the spread of HIV, with females being more vulnerable. It emerged that there was no significant relationship between poverty-stricken households and a high profile of HIV prevalence: although those households with access to luxuries had lower prevalence ratings, they were not much lower than those without such advantages.
Other noteworthy findings included those pertaining to race groups; for example, no other white or Indian populations worldwide have as high an HIV prevalence as South Africa does. Overall prevalence across the provinces is shown to be highest in the Free State, followed by Gauteng, Mpumalanga and KwaZulu-Natal, with the highest ratings being reflected in informal urban samples (shanty-towns and squatter settlements) as opposed to formal urban areas. The highest HIV prevalence amongst youth was found in the Northern Cape, with lowest being recorded in Limpopo and the North West Provinces.
Comparative ratings of HIV prevalence according to education levels were not significant; in fact, the survey reflects that there is higher prevalence amongst those with access to education as opposed to those without. It appears, then, that high HIV prevalence cannot be attributed to either poverty or low education levels. Rather, high-risk sexual activity and pre-existing sexually transmitted infections have a greater impact, and labour migration, mobility and relocation are also significant driving factors in the spread of HIV.
Professor Alan Smith from the Department of Virology at the University's medical school observed that in studies of this nature, the size of the sample itself has great bearing on the outcome - the smaller the sample, the less confident one could be about the results and analysis thereof. He felt that the survey's drop-out rates across provinces should be more closely examined.
He also noted that there were many variations in the techniques used for sampling, testing and quality assurance, and that in this study, there was only one medical doctor on the investigative team, the other specialists being social and behavioural scientists. He felt that this fact might have had some influence on the extrapolations made from the results of the survey.
One example of improbable data evident in this survey was the finding of 70% HIV prevalence amongst females in the age-group of 15 to 19 years with no sexual partner.
Professor Smith concluded that although the HSRC survey constitutes a useful addition to the existing empirical data on HIV prevalence in South Africa, it should be used as a benchmark for further investigations that would involve anonymous testing in private sector hospital labour wards and ante-natal clinics.
Professor Paulus Zulu asked which households were more infected than others, and whether rural areas showed a greater impact than urban shack settlements. Although the leader of the HSRC survey, Dr Olive Shisana, is quoted as having said: "As you move away from the main roads, the HIV prevalence in KZN starts decreasing?…", Professor Coovadia pointed out that studies conducted in the Hlabisa projects in northern KwaZulu-Natal show a 40% prevalence.
In the second presentation, Dr Suresh Kumar gave an overview of the presenting factors, diagnostic methods and treatment regimes involved in tuberculosis of the spine, a disease that results in greater morbidity than other types of TB. The progression of this disease is characterised by pain, deformity and severe compression of the spine leading to paralysis. MRI scans are used to diagnose the condition, and anti-TB chemotherapy, braces and surgery are the treatment methods deployed in these cases.
A Zambian study (Jellis, J., Journal of Clinical Orthopaedics and Related Research, No 398 pp. 27-31) of HIV in association with spinal TB yielded more questions than answers, so Dr Kumar is conducting a study based on a blood and tissue analysis of HIV-positive patients presenting with spinal TB. Dr Kumar said that this investigation provides researchers with a better understanding of the histology and clinical background typical in such patients, and that there were indicators of the HI virus bringing forth more rare conditions of this kind. However, so far, the results could not confirm that TB of the spine is increasing because of the immunological breakdown associated with HIV.
To download the PowerPoint presentation, click on the links in the right-hand column.
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Dr Suresh Kumar (left) and Prof Jerry Coovadia
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