Model fitting data: Baseline values, sensitivity analysis ranges, and sources.

<p>Model fitting data: Baseline values, sensitivity analysis ranges, and sources.</p

Sensitivity analysis—ART dropouts reinitiate ART only at CD4<200 cells/μl.

<p><b>A)</b> The fraction of HIV infections averted and <b>B)</b> The fraction of HIV-related deaths averted over the 10 year period when ART initiation rate is increased or ART dropout rate is decreased to achieve a final ART coverage of 55% or 62%. HIV-attributable mortality and disease progression rates in assumption A reduced by 50% on ART vs. off ART instead of 90%: <b>C)</b> The fraction of HIV infections averted and <b>D)</b> The fraction of HIV-related deaths averted over the 10 year period when ART initiation rate is increased or ART dropout rate is decreased to achieve a final ART coverage of 55% or 90%.</p

Assumption-specific parameter symbols, definitions, baseline values, and sources.

<p>Assumption-specific parameter symbols, definitions, baseline values, and sources.</p

General parameter symbols, definitions, baseline values, sensitivity analysis ranges, and sources.

<p>General parameter symbols, definitions, baseline values, sensitivity analysis ranges, and sources.</p

Model diagrams.

<p><b>X)</b> General model structure showing only what is consistent across all progression assumptions, A, B, C, and D. The following model diagrams show only the ART compartments (A_i) and ART dropout compartments (D_i) and do not show mortality. Key differences are highlighted in red. <b>A)</b> <i>Progression assumption A</i>: ART reduces disease progression rate (<i>σ</i>_i) by a factor <b><i>τ</i></b> while ART dropouts progress at the same rate as ART-naive individuals (<i>δ</i> = 1). <b>B)</b> <i>Progression assumption B</i>: There is no movement between ART compartments; prognosis depends on CD4 at ART initiation. <b>C)</b> <i>Progression assumption C</i>: ART patients progress to higher CD4 categories over time at a per-capita rate <i>ψ</i>_i and the rest is as in progression assumption A. <b>D)</b> <i>Progression assumption D</i>: As in assumption B, there is no movement between ART compartments. However, upon dropping out of ART, individuals move to a higher CD4 category (reflecting improvement in CD4 count on ART) but then progress at an increased rate compared to ART-naive individuals (<i>δ</i>>1; reflecting the rapid CD4 decline which occurs after dropping out of ART).</p

Projections from progression assumptions A-D.

<p><b>A)</b> The fraction of HIV infections averted and <b>B)</b> The fraction of HIV-related deaths averted over the 10 year period when increasing ART uptake rate (<i>ε</i>, solid lines) or decreasing ART dropout rate (<b><i>θ</i></b>, dashed lines) to obtain final ART coverage shown.</p

Dynamics of protective antibody and egg output during and after treatment, by immune decay rate.

<p>Results are shown for the situation where there is no reduction in transmission. Treatment was applied at yearly intervals for 5 years to school-aged children (6–15 years old) with 75% coverage. Treatment was applied the day after surveys marked *. (a) Antibody levels and (b) egg output are shown relative to pre-treatment levels for selected parameter sets which reproduced cross-sectional and post-treatment patterns in previous analyses. Results are shown separately for parameter sets with different rates of immune decay: 0.008, 0.08 and 0.8 year⁻¹; for all parameter sets, worm life span is 6.5 years.</p

Overtreatment and treatment efficiency in model 3 at different intervention coverage.

<p>(<b>A</b>)% of treatments administered over the last month which were correct (i.e.% of those treated that have current infection rather than previous infection) over the course of a 5-year intervention using a rapid test with 87% sensitivity with a testing interval of 1 or 4 years as indicated, using model structure 3 (heterogeneous FSW population, incoming syphilis infection, no regular partners), (<b>B</b>) efficiency of treatment (total number of infections averted in FSWs and clients per treatment administered) over the last month, over this same period.</p

Timing and height of peak rebound in infectious syphilis for different FSW syphilis prevalence levels.

<p>Results are shown for model 3 using the best fit parameter set and varying (transmission probability per act) between 0.01 and 1 to produce different epidemic settings. A 5-year intervention with yearly testing of all FSWs, using a rapid test of 87% sensitivity, was simulated. The x-axis shows overall pre-intervention syphilis prevalence (all infected stages) in the FSW population (high risk+low risk), and the rebound statistics shown are for infectious syphilis (primary, secondary and recurrent secondary stages) in the total FSW population (high risk+low risk).</p

Impact of intervention on prevalence and percentage of infections averted for different model structures.

<p>Impact is shown at three different time points for FSWs (<b>A,C</b>) and clients (<b>B,D</b>). Impact is presented as relative change in prevalence (compared to pre-intervention levels) (<b>A,B</b>) and percentage infections averted since the start of the intervention (compared with the situation where there was no intervention) (<b>C,D</b>). Simulated intervention assumed FSW were screened once per year with a rapid test of 87% sensitivity, with all individuals testing positive receiving immediate treatment. The thick horizontal line in each box is the median, with the box limits denoting the 25^th and 75^th percentiles and the whiskers denoting the 2.5^th and 97.5^th percentiles. Impact is shown at 6 months, 5 years and 10 years after the start of a 5-year intervention (so that 10 years is 5 years after the end of the intervention). The different population models are: (<b>1</b>) baseline-homogeneous FSW population with no syphilis infection among FSWs and clients; (<b>2</b>) heterogeneous FSW population with no infection in new FSWs and clients; (<b>3</b>) heterogeneous FSW population with syphilis infection in both new FSWs and new clients; (<b>4</b>) heterogeneous FSW population with incoming syphilis infection and regular partners of FSW included.</p