This correspondence comments on the results of Smith et al (AIDS. 2005 Mar 4;19(4):413-21) compared to their own earlier work. The two analyses use mathematical modelling to explore the issue of condom migration, or 'condom replacement', on the potential impact of microbicide use by female sex workers and yield similar conclusions. In particular, both concluded that condom migration/replacement is not a substantial concern in populations that have low levels of condom use. However the authors go on to voice their concerns that only the positive policy conclusions are presented by Smith et al. with regard to condom replacement among sex workers. They are concerned that Smith et al. claim that 'For low/moderate efficacy microbicides, the risk of HIV acquisition in FSWs will be reduced - even if complete condom abandonment occurs - if prior condom use was low'. The authors state that this conclusion ignores the fact that, with proper counselling and support, sex workers can achieve a high rate of consistent condom use with their paying clients. The authors further present evidence that replacement of condoms by microbiocides among sex workers can increase the risk of HIV acquisition. Both condoms and microbiocides should be available to sex workers, microbiocides to be used when the sex worker cannot negotiate use of a condom with her client. They call for further research to explore the issue of microbicide introduction to sex workers and that such studies as Smith et al 'raise important programmatic challenges about how best to promote microbicide use in a way that does not undermine consistent condom use.'
Foss, A. M.;Watts, C. H.;Vickerman, P. T.;Heise, L. Care should be taken when promoting microbicide use among sex workers who are able to use condoms consistently: response to Smith et al (2005). AIDS (2006) 20 (2) 303-5.