Estimates of 96% for the preventative efficacy of ART against HIV transmission, reported in 2011 by Myron & Cohen (M&C), appeared at last to place long-term containment of the epidemic in our hands. In the wake of this, UNAIDS: 90-90-90 proposed ambitious targets: 90% of those living with HIV to know their status; 90% of known HIV+ individuals to undergo ART initiation; 90% of ART initiated to achieve viral suppression. Yet – for all the promise of known ART efficacy – the question remains how easy it will be to realize these targets in practice, especially in those settings (e.g. sub-Saharan Africa) where the impact of the epidemic is at its most severe.
Perhaps less easily than one might imagine, suggest Hayes & Fidler (H&F) – a first (one year in) report of results from HPTN-071. This is a large cluster-randomized study of home-based HIV testing and treatment in 21 Zambian and S. African communities. The results derive specifically from four of the seven ‘intervention’ communities situated in Zambia. Of the c.100,000 consenting to the intervention, and visited by pairs of Community HIV Care Providers (CHiPs), 77% of men and 85% of women ended up knowing their status. (The rest were presumably not reached, or refused testing.) The estimated proportion of known HIV positive individuals who then went on to initiate ART was 42% within six months and 53% within 12 months. Over the first year, the estimated overall percentage of HIV+ adults in the four communities who were on ART rose from 44% to 61%. Obviously, these results reflect only the first year of the intervention, and CHiPs will revisit participants. At this stage no estimate of the third UNAIDS target (viral suppression) is possible. Nevertheless, the results reported by this paper give us a sense of the very considerable challenge that the achievement of the UNAIDS target represents in practice. Among the difficulties, H&F refer specifically to the difficulty of accessing male participants at their homes, and the very slow rates of initiation to ART.
There are various ways of delivering testing. Home-based testing has been trialled in populations that would otherwise be very difficult to access – e.g. in indigenous Amazonia (Ribeiro & Benzaken (STIs) (R&B); Benzaken & Peeling (STIs) (B&P). In the case of HPTN-071, its attraction seems to be the possibility of most easily achieving quasi universal coverage. At 90-90-90, achieved rates of viral suppression would be 73%; at 80-80-80, they would only be 43% – and the preventive efficacy of ART would be correspondingly reduced. Yet even the latter target seems ambitious. So far as the testing is concerned, however, the 90% is within reach – at least in Zambia. The real challenge will be second (and probably also the third) stage of the cascade. Other studies indicate that HPTN-071 is not unique in seeing large fall out at this point (see Schwartz & Baral (STIs)). R&B and B&P point to further problem likely to arise at the stage of rolling out this kind of preventative ART intervention – namely that of maintaining the quality of POCT testing (Benzaken & Peeling (STIs)).