One of the best ways to determine if HIV prevention activities are effective among female sex workers is to see if prevalence is decreasing among young sex workers. Please look at the attachment with data from sentinel surveillance in 2007 and 2008. There is not a clear trend here. If sampling was performed in the same way during both rounds then this is not good news. If sampling was performed differently then no conclusions can be drawn. Will any readers tell us whether sampling in 2007 and 2008 was the same? Any other comments? …