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

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