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HIV prevention through HAART: a victim of its own success?

28 Feb, 17 | by Leslie Goode, Blogmaster

A recent study (Kalichman & Allen (K&A)) involving a series of four cross-sectional surveys (1996-2016) at a Gay Pride event in US Atlanta Georgia adds to the mounting body of evidence that substantial changes have occurred in community-held beliefs about the safety of certain sexual behaviours in the era of HIV treatment as prevention.

It might seem surprising, in view of the known effectiveness of ART as a preventative tool, that its deployment has generally failed to deliver the preventative benefits that might have been anticipated.  It is essential to achieve progress right along the ‘treatment cascade’, including, not only access to testing, but integration into treatment and viral suppression, for those benefits to be realized.  The fact remains that levels of infection amongst MSM, even in countries that have scaled up testing and treatment, have remained stable or are actually rising.

The obvious hypotheses, tested by K&A in this study, are that, 1., the perception of safety on the part of MSM has led to an increase in condomless anal sex, and that, 2., the growing incidence of STIs resulting from these sexual practices has itself had a direct impact in reducing the protective effects of ART.  (Of course, this is not to deny that sizeable proportion of the MSM community in the US – as in Australia (Mao & de Wit) – be successfully engaged in deliberate HIV risk-reduction strategies.)  The four surveys adopted identical measures and procedures, and involved ascertaining proportion of condom use during anal intercourse and number partners over the previous six months as well as assessment of beliefs regarding the preventive effectivess of ART (nine items of the questionnaire).

Results were as follows.  For HIV negative men: condomless anal sex (CAS) increased from 43% (1997) to 61% (2015); reporting two or more condomless sex partners from 9% to 33%.  For HIV positive men:  CAS from 25% to 67%; reporting two or more condomless sex partners from 9% to 57%.  As regards beliefs that ART was protective, comparisons across survey times indicate a main effect for year of survey, F(3, 1829) = 6.3,p<0.01, with an effect across survey year for men who engaged in CAS, F(1,1829) = 9.3,p<0.01.  Most evident from figures is a precipitous drop in perception of risk amongst both groups between the third and fourth survey (2006 and 2016).

K&A’s hypotheses (one or both) would seem to be corroborated from another quarter by the observed association with the introduction of HAART of an increased infection rate of gonorrhoea and syphilis (Stolte & Coutinho (STIs)) and of viral STIs (de Laar & Richel (STIs)).  Indeed rates of MSM syphilis increase coinciding with HAART introduction have been so dramatic in some places (e.g. Buenos Aires (Bissio & Cassetti (STIs)) as to lead to a hypothesis that HAART agents may actually be impairing immunity to the virus (Rekart & Cameron (STIs); Tuddenham & Ghanem (STIs)).  Whatever the validity of the latter hypothesis, evidence of STI epidemics is consistent with evidence of attitudinal and behavioural changes, such as those proposed by K&A.

Where next for HIV prevention in New Zealand?

29 Jan, 16 | by Leslie Goode, Blogmaster

A recent issue of the New Zealand Medical Journal (NZMJ) (128: vol. 1426) gives pride of place to a series of papers that reconsider the way forward for HIV prevention in New Zealand (NZ) against the background of the past thirty years.  Recent contributions to STI journal by these authors analyse the behavioural surveillance data from NZ (Saxton & Hughes (STIs); Lachowsky & Summerlee (STIs); Lachowsky & Dewey (STIs)); the papers in NZMJ set these findings against a broader background (Saxton & Giola; Hughes & Saxton; Dickson & Saxton; Saxton & Ludlam).

Broadly speaking, the situation in NZ resembles, both in nature and scale, what we find in Western European countries: namely, persistent but relatively low-level epidemics concentrated in the MSM population (above all, in Auckland), and among heterosexual individuals of foreign extraction (Dickson & Saxton).

The distinctiveness of the NZ epidemics, as against those of Western Europe, lies primarily in geo-political factors: such as migration from sub-Saharan Africa, which reached a peak in 2006 before abruptly declining – or the changing demography of Auckland with its large populations of South Asians and people of Pacific origin (Dickson & Saxton: Lachowsky & Summerlee (STIs)).  The main emphasis of the NZMJ papers, however, is on issues that will have a familiar ring to West European readers – such as the importance of achieving a balance between public health and clinic-based approaches to HIV control.

Overall, their account suggests some considerable degree of success on the part of health interventions – but in the face of a public health challenge that is constantly evolving and may yet prove intractable.  As regards the success, some behavioural surveillance data indicate levels of condom use with casual partners of 85% (Hughes & Saxton; Saxton & Hughes (STIs));  The challenge is represented by the growing minority who do not perceive HIV as a threat on account of new treatments (Hughes & Saxton; Saxton & Ludlam). There also remain, as elsewhere, the problems of high levels of undiagnosed HIV (c. 20%) and relatively late presentation to health services (over a third of MSM at CD4=<350/mm3).  A things stand, the worst kind of scenarios seen amongst gay communities in Thailand or the US would appear to have been averted.  Nevertheless, the epidemics show every sign of persisting, and, given a level of diagnosis that it is marginally higher than seen hitherto, may still turn out to be on an upward trajectory.

A key focus of the NZMJ editorial (Saxton & Giola) is on the continued importance of behaviour-based interventions in a world where the momentum seems to have shifted to clinic based control involving pharmaceuticals.  They highlight the danger that the medicalization of HIV prevention could lead to a disinvestment in behaviour-based interventions, which, they imply, would not be conducive to controlling the epidemic.   In this regard, the authors cite Phillips & Cambiano who argue that a mere 10% reduction in condom use would, without improvements in testing levels and ART initiation, result in a doubling of HIV incidence over 15 years.

The real-life STI prevention potential of the male condom: hard to fulfil, hard to evaluate

23 Mar, 12 | by Leslie Goode, Blogmaster

In the face of 340 million incident cases of STI worldwide each year, UNAIDS in a recent statement deemed the male latex condom “… the single most efficient, available technology to reduce the sexual transmission of HIV and other sexually transmitted infections”.  Sadly, though the condom may be effective in vitro, this potential proves hard to realize use in real life.  Sustained condom use requires levels of commitment such that, even in the case of discordant heterosexual HIV couples, studies indicate fewer than half of participants report regular use.  In the light of this, the Australian journal Sexual Health has devoted a special issue to condom use – recognizing it to be a “complex behaviour embedded in the fabric” of social relationships.  Attention is given both to data regarding the behaviour itself (including errors and problems of condom use), and to the methodological problems affecting its evaluation by recent research.

Individual reviews cover China, Central and Eastern Europe and Sub-Saharan African.  There are also papers on the female condom and on the issue of “risk compensation” – i.e. where the introduction of one preventative method (e.g. vaginal microbicides) impacts on the use of another (e.g. condoms).

Two systematic review papers, reflecting the two-fold concern of this special issue with the behaviour itself and methodological issues around its evaluation, offer a global perspective on condom use.  The first of these – a review of the literature regarding condom use errors and problems (Stephanie A. Sanders et al.) – leaves the reader with a bewildering sense of the disparity in the importance assigned by studies to the various causes of “condom failure”.  Statements abound such as that “breakage rates ranged from 0.8% to 40.7% of participants across 15 studies”.  The reader may wonder what there is to learn from such data, other than that condom use is indeed a complex behaviour and difficult to evaluate scientifically.

The other systematic review paper (Richard A. Crosby & Sarah Bounse) is complementary to this.  It deals specifically with the methodological problems of evaluating the link between condom use and STI, focussing exclusively on prospective studies.  Forms of misclassification bias are rife, the authors claim.  The most serious derive from the difficulty of determining, when infection takes place within the recall period, whether events of condom-protected sex occurred before infection, or after infection.  Other sources of misclassification bias involve failing, where figures are given for number of infections for a given level of condom use, to control for “use errors” such as breakage, slipping, or incomplete use.

Ultimately the critical question facing policy formers is this: whether protective effect of condom use warrants the full support of public health efforts to keep condoms to the forefront of STI prevention?  It should be borne in mind that all the potential forms of study bias regarding condom use tend towards the nul hypothesis (i.e. they underestimate the effectiveness of condoms).  In the light of this, the authors affirm that the threshold for sufficient protective effect has probably already been crossed.  Yet clearly more definitive findings would greatly assist the cause of deploying condoms as part of public health efforts.  To this end, the paper seeks to explain, and thereby avert, the causes of “error variance” between studies of condom effectiveness (variance not determined by real differences of the relation between condom use and STI).

Sexual Health 9: 1, 2012

Stephanie A. Sanders, Robin R. Milhausen et al., Condom Use Errors and Problems: A Global View, pp.81-95

Richard A. Crosby and Sarah Bounse, Condom Effectiveness: Where are we Now, pp.10-17



R. Crosby, W.L. Yarber et al.,  “Two heads are better than one: the association between condom decision-making andcondom use errors and problems”, Sex Transm Infect 2008;84:198-201 doi:10.1136/sti.2007.027755

And for a perspective on promoting condoms through religious leadership, Willms et al in Sex Transm Infect 2011;87:611-615 doi:10.1136/sextrans-2011-050045





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