UNAIDS 2016 Report: How a ‘life-cycle’ approach can help the world ‘get on the fast track’ to HIV prevention

‘Get on the Fast Track: a Life-cycle Approach to HIV’ is the latest UNAIDS report, following on from the UN Assembly’s 2016 declaration of commitment to ‘Fast Track’ goals for ending the HIV/AIDS epidemic. The major theme of the ‘life-cycle’ appears to owe much to the findings of the South African CAPRISA study – above all, the idea of a transmission cycle between younger (25 year-old) women and older (>25 year-old) men.  Broadly, phylogenetic analysis reveals that the prevailing pattern of transmission is as follows.  Younger women appear to get infected through casual relationships with considerably older men, who have, in turn, been infected by their longer-term partners; in time, the younger women grow up and form longer-term relationships – and the cycle is repeated.  The former group – younger (≤25 year-old) women – appear to be more vulnerable to infection than men of the equivalent age due to complex social factors, and have recently seen only c. 6% declines in annual incidence; older (>25 year-old) men have incidence rates that have remained obstinately high despite all recent efforts to reduce them.  These are best explained by poor rates of testing, integration into treatment, and viral suppression making them a potential risk to non-HIV-infected partners.

Diagnosing a problem is one thing; framing the solution quite another.  In case of the younger women, the dominant factors appear to be structural and societal – e.g. gender inequalities.  These are difficult to address without major social and political change.  The authors suggest a number of prevention tools, including sexual education in schools, the introduction of pre-exposure prophylaxis (PrEP), and social transfers.  However, recent trials of PrEP in sub-Saharan Africa do not bode well for this intervention (STI/blogs/’Failed PrEP trial’; STI/blogs/‘Another failed PrEP trial’); while the evidence for the effectiveness of sexuality education and ‘social transfers’ is far from conclusive (School-based Sexuality Programmes/STI/blogs; STI/Galarraga & Sosa-Rubi; STI/Minnis & Padian; STI/Khan & Khan).  However, in the case of the other group – i.e. older men – the obstacles to HIV prevention (poor rates of testing and viral suppression) may be less intractable, and the report proposes a number of very practical measures that could help, including: distribution of self-test kits through female partners attending ante-natal clinics (STI/blogs/’Partner-delivered STI testing’); simplifying ART regimens so individuals have to take just one tablet a day; shifting from CD4 count testing to viral load testing.

The report also has much to say about other phases of the life-cycle, as well as about ‘key populations’ (estimated 45% of new infections).  Regarding the latter, the authors report the stability, or even rise, in new infections amongst sex-workers, drug-users and MSM. They emphasize the negative impact of criminalization of key populations and same-sex relations (73 countries) (see STI/blog/’HIV criminalization’/; STI/blog/’Health workers violate human rights’), the very low levels of domestic funding (on average, only 12% of total spending on MSM prevention), and the relatively young age of many in the ‘key populations’.  The authors recommend ‘comprehensive’ programmes for these populations incorporating access to a range of health care programmes, such as the Red Umbrella programme for sex workers in South African, and the ‘Targeted Strategy Plan’ for the transgender population in Lima, Peru.