Archive for the ‘Treatment for prevention’ Category

Empirical evidence that achievement of UNAIDS 90-90-90 can deliver promised HIV elimination?

Friday, December 15th, 2017

The achievement of the UNAIDS 90-90-90 targets would reduce levels of viral suppression amongst HIV+ people to 73% by 2020. The target is set at this ambitious level because, modelers suggest, it would bring about the elimination of HIV by 2030. In sub-Saharan Africa the challenge seems so great – especially in regard to the element of engagement and retention in treatment (Mountainous Challenge/STI/blogs; Wringe & Skovdal/STI) that the question of whether the necessary interventions would really bring about the proposed goal of the elimination of HIV – of whether the modelers are right – disappears off the horizon.

Results of the recent Rakai Community Cohort Study (Grabowski & Chang (G&C) from 30 communities (17,879 persons) in Uganda, over the course of 12 surveys undertaken between 1999 and 2016, show the following trends. First, an increase in viral load suppression amongst HIV+ individuals since ART scale-up from 42% (2009) to 75% (2016), and in voluntary male circumcision since the beginning of the study from 15% (1999) to 59% (2016). But also – apparently as a result of these interventions – a decline in HIV incidence from 1.17 cases per 100 person-years in the period before scale-up to 0.66 cases per 100 person-years in 2016. Some indication of how much this may be due to ART as against circumcision is suggested by difference between the decline amongst men (who have benefited from both interventions), which reached 0.46 in 2016, and women (who have benefited – at this stage – largely from ART), which reached 0.68. The contribution of consistent condom use has evidently had little to do with the decline, since it has remained largely unchanged since the inception of the study.

As regards viral load suppression, this population has met the UNAIDS target and is presumably on course. However, incidence per 100 person-years needs to reach 0.1, according to the modelers, for elimination to be achieved. The working-through of the epidemiological effects of already achieved levels of circumcision to the female population should further help things on their way. Moreover, the UNAIDS target of 80% circumcision may be achieved in the coming years.

The authors claim this is the first study to demonstrate the population level effect of the combination strategy for HIV prevention. How far are its encouraging conclusions generalizable? It is true that with high coverage of testing services (98%) the conditions in Rakai are favourable; yet data from the National AIDS Control Programme of Uganda indicate that the dramatic scale-up of the combination strategy has been replicated more widely, with ART coverage of 68% and circumcision at 54% (as opposed to 69% and 59% respectively for Rakai). In other sub-Saharan countries, the picture may be rather different (Wringe & Skovdal/STI) – though data from the Swaziland HIV incidence measurement survey 2017 shows a comparable relationship between relatively steep increase in viral suppression and a decline in incidence (Achieving UNAIDS 90-90-90: More haste, less speed/STI/blogs; SHIMS 2).

What is the potential of ‘Treatment for Prevention’ in fighting HIV/AIDS?

Thursday, November 9th, 2017

UNAIDS 90:90:90 appears to have set the course for a global ‘treatment as prevention’ strategy. In 2015 the US revised its National HIV/AIDS Strategy (NHAS) to harmonize its goals with UNAIDS 90% targets for testing, engagement in care, and virological suppression. Though the HIV/AIDS community have been nervous about the impact of the recent change of administration, the expenditure underpinning the NHAS has been retained despite 18% cuts to the Department of Health and Human Services budget (Trump and HIV/AIDS spending).

It is no doubt with a view to maintaining this political course that Borre & Walensky have recently sought to quantify the benefits of the revised goals as against ‘current pace’ by using mathematical simulation to project five- and twenty-year outcomes. Given the disproportionate implication of black MSM in these effects (they face a 50% lifetime risk of infection), outcomes are given for this group as well as for the US at large.

These outcomes are impressive. Achieving NHAS targets, as against current pace, will cause rates of transmission over twenty years to decline: across the general population, from 2.8 to 1.7 per 100 person years (PY); among blacks MSM from 4.3 to 2.7. This will result in a decrease in deaths from 750,000 to 551,000. Cost-effectiveness, as against current pace, is estimated at $68,000 per Quality Adjusted Life Year (QALY) over the whole population, and at $38,300 per QALY for black MSM – though the authors point to the high proportion of costs represented by the ART drugs, and the potential for improvement in cost-effectiveness, if there were a significant reduction in ART cost. As for affordability, NHAS revised targets would require only a 3% per year increase in budgetary allocation.

UNAIDS 90:90:90 represents an altogether more ambitious – and, arguably, less realistic – target in medium- or limited-resource settings. Some have cautioned against the advocacy of ‘treatment for prevention’ (TfP) as a global single plank intervention strategy – and on two counts. First, Kielmann & Cataldo/STI and Wringe & Renju/STI warn that the evaluation of success in terms of TfP targets can result in the adoption of short term or culturally inappropriate measures that could have long-term implications for public attitudes towards care providers. For example, the greater status often accorded to patient-experts in inadequately resourced contexts can result in the promotion of culturally regressive attitudes that may be counter-productive in the long-term business of establishing proper engagement in care (see ‘More haste less speed’/STI/blogs).

Griensven & Lo/STI oppose TfP on altogether more radical grounds. With the MSM populations of the cities of the Asia-Pacific region, they argue, infection is so acute and transmission so rapid that any TfP-based intervention is doomed to be ineffective: HIV will have been widely disseminated before linkage-to-care can take place. Needless to say, this critique of TfP goes along with advocacy in the case of these populations of an approach that ‘widens the cascade with a preventive extention’ – that is to say, PrEP.