This is a letter commenting on a previous article in the same journal [Smith, R. J. et al.: Evaluating the potential impact of vaginal microbicides to reduce the risk of acquiring HIV in female sex workers. AIDS (2005) 19 (4) pp. 413-421]. The authors of the letter, who have also done work on this subject, agree with most of the conclusions of Smith et al., but argue that they did not pay enough attention to situations where condom use is high, that such situations are not uncommon and that in these cases microbicide use can lead to reductions in condom use and increases in HIV risk.
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. AIDS (2006) 20 (2) 303-305.