To some extent, the Mosaic study may have provided some of this analysis. However, the study could not possibly account for all of the costs of scaling up screening and treatment to the level of universal treatment.
For example, the cost of providing treatment through existing infrastructure may be relatively inexpensive, but once that infrastructure is fully utilised, the cost of scaling up could increase the cost of care substantially. New laboratory and treatment facilities would need to be built, often in remote settings. The healthcare workers to staff these facilities would have to come from somewhere — and be trained. Millions of asymptomatic people with HIV would have to be identified and screened. Logistics, supply chain and quality control costs could grow dramatically.
An advantage of the more simplified WHO guidance is that it is scaleable to the primary health level — while introducing the composite approach to the primary care level could be significantly more difficult. After his talk, Dr Mazonson was asked about this.
“They [the WHO guidelines] might be 'scaleable' but one of our key take home points is that you really don't get at the transmission component through the CD4 count. Because the people that are really the sickest, aren't really transmitting the disease that much because they're not that sexually active. It's the people with high viral loads who you're completely missing. So, basically the 3 by 5 programme makes sense from an equity point of view on treating the sickest patients first. But in terms of getting an economic [handle] on the disease, you never do that because your are kind of 'bottom feeding'. At the top you keep cycling the disease and keep creating more and more transmission which you don't pick up unless you're monitoring the viral load.”
And yet, at least one other study by Baggaley et al has concluded that ART will only have a limited impact upon transmission. Some of the paper’s conclusions are partly the result of some rather bleak assumptions about the efficacy of treatment, the likelihood of resistance developing and/or being transmitted, and the ability of African countries to scale up. “In reality, scaling up programmes is likely to compromise quality, meaning higher dropout rates and mortality and treatment failure, negating the beneficial impacts of ART and increasing the rate of drug resistance emergence,” Baggaley wrote.
So far, there are few data on ART programmes in Africa to support the paper’s more pessimistic predictions. However, the paper raises at least one interesting point: that the coverage of the ART programme may need to be quite high in order to have a significant impact upon HIV transmission at the population level.
And to approach anything near universal treatment won’t only take more money up front, it require political will that has thus far been lacking in the country examined in the Mosaic paper. In the discussion session after Dr Mazonson’s talk, one audience member asked whether he had presented his results to the South African Government, and what their response had been.
“The answer is no,” said Dr Mazonson, “but we'd love to do so.”
The irony is of course that while Dr Mazonson was presenting this study, South Africa’s exhibition booth at the World AIDS Conference featured baskets of lemons, beetroot, African potatoes and clumps of garlic which the Minister of Health proposed as a being a equally valid choice for treatment of HIV (see http://www.health-e.org.za/news/article.php?uid=20031487).
Even were South Africa to adopt something like the composite guidelines or any of its aspects, such as a higher CD4 threshold for starting treating, there would have to be a major change in the leadership to reach anywhere near the coverage required for the Mosaic model. As for viral load, at present South Africa’s programme only pays for the test after someone’s CD4 cell count has fallen below 200.
Botswana, on the other hand, has the progressive leadership in abundance — and perhaps, eventually, the capacity to demonstrate the accuracy of the Mosaic’s study’s predictions. After all, data have recently shown that the government’s ARV programme has lead to a reduction in the national adult mortality (see http://www.aidsmap.com/en/news/FA96D301-87C5-43E5-BB63-6F6921A12F7A.asp)
“In the end analysis, they’ll say it [changing the CD4 threshold to 350] is expensive, but by the same token, all these will eventually end up on treatment,” said Dr Gaolathe at the Botswana conference.
Furthermore, they may be in more immediate need of treatment than previously thought. Data now suggest that people with 200-350 CD4 cells are much more likely to die or progress to serious illness than people with over 200 CD4 cells in the UK, Europe or America (http://www.aidsmap.com/en/news/37AEC801-171D-4C0F-B95F-413F922CE4CD.asp).
In that South African study, 52% of people followed after HIV diagnosis in the Cape Town HIV Cohort died before they reached WHO stage 4 (AIDS), and the study found that South African patients with a CD4 count between 200 and 350 with WHO stage 3 disease were 1.9 times more likely to die during a median 16 months of follow-up than their counterparts in high-income country cohort studies, presumably due to higher rates of TB.
However, not every expert in attendance at the Botswana meeting believes the step is advisable.
“You should stop any talk as far as giving antiretroviral care at 350. I think it’s not going to happen in the U.K. It shouldn’t happen here,” said Dr Brian Gazzard of Chelsea Westminster.
Indeed, the BHIVA guidelines in the UK do not make a blanket recommendation for treatment of people with less than 350 CD4 cells. However, they do recommend something somewhat closer to what was investigated by Bogaards et al. Within the range 200 to 350 cells, individuals with a viral load above 100,000 copies/ml or a CD4 cell count falling by more than 80 cells per year may be considered for earlier intervention. In fact, a marked decline in CD4 cell counts within this range could serve as an alternative to viral load measurements where that capacity is not yet available, or too expensive to use routinely.
However, any step that Botswana or any other country takes in the direction of expanding the number of people eligible for ART must not come at the expense of people currently on treatment. There is some truth to the concern that too rapid a scale up could result in a decline in the quality of service. Most countries may first need to focus on streamlining patient management and decentralising care in order to prevent overcrowded clinics and preserve the quality of care.