Brussels, 14 March 2006
Two new studies from researchers at Imperial College, London, and the University of Berne, Switzerland, raise difficult questions about whether antiretroviral therapy (ART) is effective in preventing the HIV epidemic from spreading in low resource countries.
ART has been very effective in the West at prolonging the lives of HIV-infected people, decreasing the rates of infection between people and even acting as a preventative in those who may have suffered an infectious encounter. The Highly Active Anti-Retroviral Therapy (HAART) has given people who previously had no hope of recovery an almost-normal life-span and the possibility of living an almost-normal life.
The Swiss study, published in The Lancet, examined HAART programmes in 18 developing countries and compared the results to a network of 12 studies in Europe and North America. They found that 'Antiretroviral therapy is feasible and effective in low income settings, but, compared with industrialised countries, mortality is high in the first months. Eligibility for ART and the need for treatment of tuberculosis should be determined earlier, and HAART should be started before serious comorbidities develop,' said author Dr Matthias Egger.
However, a second new study, published in The Public Library of Science, suggests that while ART undeniably prolongs the lives of those taking it, the use of ART may in fact encourage further infections, rather than preventing them. But the result is a complex one. The model developed shows that in the absence of adequate education in sexual behaviour, those people taking ART will have an improved quality of life and so revert to sexual behaviour and infecting partners.
The team from Imperial College modelled the spread of HIV once ART is introduced. They based their models on southern African countries. While Africa contains only ten per cent of the world's population, it has more than 60 per cent of the HIV-infected population. While some countries, such as Uganda, have recorded falling rates of infection, South Africa, Botswana, Lesotho, Namibia and Swaziland are all still recording 30 per cent or more of pregnant women infected with HIV. The study looked at the effects of introducing widespread ART into such populations, and found that the rates of infection may actually increase.
Because ART can reduce infection rates, it seems logical that if the drugs are distributed widely, then it will reduce the numbers of people being infected. But, 'HIV epidemics in sub-Saharan Africa are not amenable to control through treatment, regardless of the extent of ART roll-out, and must be integrated with prevention methods,' reads the report. Treatments must go hand-in-hand with prophylactic use - specifically condoms.
The use of ART has been the subject of intense pressure in South Africa, where the Treatment Action Campaign (TAC) lobbied for the government to approve its use, which it reluctantly did. In South Africa, ART is now given to the country's six million-strong HIV positive population, who enjoy an improved quality of life as a result.
Rebecca Baggaley from Imperial College was one of the authors of the piece and spoke to CORDIS news. 'When it comes to whether ART is a good thing - it is, but how much will it benefit people? If you increase access, but do not have the infrastructure, then it becomes an ethical decision. So, do you open it up and provide drugs for all, or restrict access but then ensure higher rates of success in those people?'
Dr Baggaley also pointed out that not all ART treatments are the same. HAART regimes may be 'gold standard', and include testing of CD4 counts, checking tuberculosis status, and providing a range of medication. In low-resource settings, however, drug regimes will be standardised and treatment may only start when AIDS symptoms are noticeable, so CD4 counts would be low, which limits ART effectiveness in both prolonging life and reducing infection rates.
If money is ploughed into drug therapies, there is likely to be less money for other approaches, such as counselling for changes in sexual behaviour. 'We need behavioural surveys and to follow what happens,' says Dr Baggaley. 'Success depends upon how prevention initiatives will be affected. We need surveillance of how behaviours change. Resources we expect in 'gold standard' trials, including monitoring, may be absent.'
If drug therapies are favoured, then how are cases prioritised? 'If resources are limited, there can be no guarantees - first and second round treatments may have standard funding. But when those cases move to the third and fourth round of treatment, will this stop new cases from being put on the first round?' asks Dr Baggaley.
In the medium-term, more and more data will build better and better models. 'We need to look at particular initiatives to change behaviour, and as the information comes back, the model will improve,' says Dr Baggaley.
ART, once given, would be unethical to remove, even when the effects could be paradoxical or even damaging. The paradox is that ART is effective, but possibly counterproductive in the absence of enough resources. 'As the pace of ART roll-out across southern Africa quickens, difficult decisions regarding the allocation of finite resources will have to be made,' reads the study.
The EU is funding research into HIV and AIDS under its European and Developing Countries Clinical Trials Partnership (EDCTP). The programme integrates the research and clinical intervention experience of all participating countries within one joint programme to implement extensive, coordinated and in-situ clinical trials for the development of new drugs, vaccines, microbicides and diagnostic tools for the treatment of HIV/AIDS, malaria and tuberculosis. The initiative is long-term, envisaged to run for between ten and 20 years.