Figure 4

Change in HIV and chlamydia incidence, due to routine chlamydia screening among HIV-infected MSM in-care. Percentage change in the incidence of HIV or chlamydia among MSM, ten years after the introduction of routine chlamydia screening among HIV-infected MSM in care. The percentage change is calculated compared to the current situation, with only opportunistic chlamydia screening. (a) Percentage change in HIV (blue) and chlamydia (red) incidence, with routine chlamydia screening carried out every twelve, six, or four months. The boxes represent the interquartile range of the results; the white segment within the box represents the median of the results; the line segments above and below the boxes show the whole range of the results. (b-d) The percentage change in HIV incidence due to routine chlamydia screening of HIV-infected MSM in care every six months, plotted against three of the uncertain parameters: the number of acts of unprotected anal intercourse (UAI) per year per multiple-acts casual partner; the factor increase in susceptibility to HIV due to chlamydia; the factor increase in HIV infectivity due to co-infection with chlamydia.