This is part of a series of articles written for NATAP by a guest writer--Dr Mike Youle. Other NATAP guest writers for Durban include Mike Norton, a physician's assistant in New York City, and Dr. Graeme Moyle, a physician at Chelsea & Westminster Hospital in London, UK.

DURBAN WORLD AIDS CONFERENCE
Tuesday, July 11
Durban, South Africa
Reported by Mike Youle, MD, Royal Free Hospital in London, UK

Monday 9th

This is a conference where the discussion about how to treat HIV is mainly replaced by that of which strategies are applicable to use in populations that are heavily saturated, but in which the infrastructure to deliver even the basics of care are lacking for the majority. The opening speech by Judge Edwin Cameron was direct and forceful in its message. Realism about the epidemic that rages across Africa, a political will to move forward with at least some action and less diversive rhetoric is what is needed here and now. Money is the key for many of those who cannot access therapies that they would benefit from and it is simplistic to say that treatment is neither appropriate nor sustainable in the African setting. Not laying the blame at one door alone he stated that ëDrug companies and governments have engaged in a colusive paralysisí which has only been exacerbated by many international agencies.

Several presentations today highlighted aspects of the epidemiology that reflect the complexities discussed by Professor Roy Anderson in his overview plenary. For instance when a vaccine preparedness study was conducted in Kenya [MoOrC128] the risk of HIV acquisition dropped significantly over the period of follow-up as did other sexually transmitted diseases. This suggests that within a cohort there may be time- related alterations in HIV incidence that may impact on the ability of the group to show significant reduction in seroconversions when the vaccine is introduced. There appears to be a correlation in several studies between circumcision and lowered rates of HIV transmission although the cultural and religious confounding factors that exist may require randomized studies to determine the true benefit of this as a prevention strategy. One study in the Luo people of Kenya revealed a willingness to consider the use of circumcision for this end [MoOrC196]. There was a perception that cleanliness may be improved and sexual satisfaction increased as well as a reduction in HIV and STDís. Finally the link between oral sex and transmission of HIV in men who have sex with men (MSM) was evaluated in the Montreal omega cohort study [MoPpC1100]. Through 1546 person years of follow-up in 981 subjects seroconversion occurred in 12 men. The odds ration for unprotected anal sex ranged from 3.8 with any partner to 8.3 with a casual partner, whilst unprotected oral sex with a known HIV positive casual partner was 6.1; p=0.058 (2/35 versus 9/922). The public health implications of these findings remain to be determined.

For the first time at a major AIDS conference there was a plethora of data on resource use and cost. This reflects the increasing awareness of the issue of money in the epidemic since effective therapy is available but is either perceived to be too expensive to use or not cost effective (although all available evidence for the developed setting suggests otherwise). What is clear is that the total cost of care is rising as numbers of HIV infected individuals increase. Modeling studies included, the cost-effectiveness of the female condom in commercial sex workers in South Africa that showed cost savings of around $9,000 for a one year program for 1000 participants [MoOr131] and an economic model of mother to child transmission in Canada which showed a cost-saving of $0.5million per case averted [MoPeC2473]. The cost of viral load testing was potentially reduced in a study validating a modified p24 antigen test which was 77% cheaper that the standard PCR test and gave comparable sensitivity [MoOrA107], whilst the experience of the physician was a factor in cheaper care in a study from Boston [MoOrB119]. Those patients cared for in the HIV clinic were approximately 50% cheaper than those cared for in a similar manner but in a non-HIV specialist clinic. These data continue to support the concept of HIV care as a specialty. Finally the economic issues around vaccine acceptance were studied in 900 randomly selected Kenyans [MoOrC127]. Four out of 10 were not willing to receive a vaccine that was less than 50% effective whilst the majority would not or could not pay more than $2 for the vaccine were it available. This suggest more economic acceptability research needs to be conducted in this area.

With regard to novel treatments there was not a lot presented. In a study from Baltimore the subjects from AVEG vaccine protocols 022 and 022A were examined using an assay for R5 resistance in PBMCís [MoOrA220]. Subjects who had received 2-6 vaccinations with ALVAC vCp205 canary-pox vector vaccine and then were boosted with 0-2 boosts using SF2 rgp120 showed env and gag CTL specificities associated with 1-2 fold resistance to R5. The fact that X4 virus derived vaccines can induce R5 resistance has encouraging implications for vaccine development.

Bentwich and co-workers supplied further data regarding the importance of suppressing antigenic challenge due to co-infections. Data from Ethiopian Jews infected with helminthic worms were treated and showed commensurate falls in HIV viral load which were not seen over time in those who were not infested. This expands on the increasing body of data that argues that upregulation of the immune system by co-infections causes viral load increases and may lead to more rapid disease progression. The converse of this is that effectiove suppression of HIV allows a reduction in infections associated with immune deterioration. Several studies added to the body of evidence that with HAART there is a reduced necessity for porphylaxis against PCP and toxoplasmosis  [MoPeB2278, MoPeC2283]whilst a reduction has now been reported in invasive aspergillosis after HAART therapy [MoPeC2492].