New research could bolster arguments for a controversial approach that could eradicate HIV transmission in South Africa within five years, said Dr Brian Williams of the South African Centre for Epidemiological Modelling and Analysis (SACEMA).
The "test and treat" approach is based on mathematical modelling and pairs aggressive HIV testing campaigns with almost immediately putting people found to be HIV positive on treatment. In theory, this model would use early treatment to lower viral load (the amount of virus in the blood), and lower the likelihood of transmission, eventually cutting HIV prevalence rates.
A report published in the current issue of AIDS, the Journal of the International AIDS Society, is based on a study that followed about 14,000 new mothers in Zimbabwe for about two years from 1997 to 2000 after the birth of their children.
The research showed that HIV-positive new mothers were at much greater risk of dying than their HIV-negative peers, even when the positive women had a CD4 count (which measures immune system strength) of 600 to 1,000 and was equal to or higher than that of HIV-negative women.
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Although the research was conducted before antiretrovirals were available in the public sector, the data may have answered a crucial question in the test and treat debate.
"One of the questions around doing [the test and treat model] has been that even if you accept that there is public health benefit of testing and treating everyone, what does that do for the individual?" Williams told IRIN/PlusNews.
"The study's authors showed that even at CD4 counts of up to 1,000, mortality among the HIV-positive women was about 50 times higher, [and] it's in the patient's interest too, to start treatment early," said Williams, who spoke in favour of test and treat at the Conference on Retroviruses and Opportunistic Infections (CROI), and the annual meeting of the American Association for the Advancement of Science, both in the Untied States.
John Hargrove, co-author of the report, said the study was one of a very few that had compared the mortality rate of untreated HIV-positive adults to their HIV-negative peers and had tied this to CD4 counts - the research could never be ethically replicated in today's expanded treatment environment.
However, there are concerns that the approach is unrealistic, given low testing uptake globally, and that putting more people on treatment earlier may lead to poor adherence and contribute to drug resistance.
The approach is being implemented on a trial basis in high HIV prevalence areas of the United States, including the District of Columbia and New York City. The US infection rate is about 0.6 percent, according to UNAIDS.
|The study's authors showed that even at CD4 counts counts of up to 1000, mortality among the HIV-positive women was about 50 times higher...|
Testing and treating, funding and debating
Williams said doing away with specific requirements like the need to verify CD4 counts would reduce costs, but estimated that it would still cost a country like South Africa at least US$2 billion a year to implement the test and treat strategy nationally.
"Costings show that the cost of providing ARVs will be roughly balanced by the costs saved in [relation to] opportunistic infections and hospitalisations," he said. "We need a big investment initially, but in the long term we are going to be saving money. It's the only real prospect for actually stopping the epidemic."
However, in a debate about test and treat in late 2009, Dr Francesca Conradie, deputy director of the University of Witwatersrand Clinical HIV Research Unit, argued that money was not the only issue, and that test and treat models ignored current realities, including low testing uptake.
According to the 2008 South African National HIV Prevalence, Incidence, Behaviour and Communication Survey, only about half the people 15 years and older have been tested for HIV.
Conradie also argued that the US had low HIV prevalence, whereas South Africa's HIV population was simply too big to meet the treatment targets cited by current test and treat models to make the approach affective - the country would have to reach more than eight times the number currently on treatment to meet the targets.
With an HIV prevalence rate of about 18 percent and more than half a million people on treatment, South Africa runs the world's largest ARV treatment programme.