Table 1

Model inputs for the PPT model for different settings

Input name		Model variable (supplementary material contains equations)	Johannesburg4 7	Cotono,15–17	Laos1	Free State2	Comments/range and source for biological parameters
NG biological parameters:^†
Duration of NG with existing treatment in months	Males	1/μⁿ₀	2.6	1.5	4.3	3.1	3–9 months23
	Females	1/μⁿ₁	2.6	1.5	9.3	5.0
CT biological parameters:
Duration of CT with existing treatment in months	Males	1/μ^c₀	Assumed to be quarter of female CT duration				2–4 months23
	Females	1/μ^c₁	7.7	3.4	22	8.3	6–24 months23 28
HD biological parameters:
Duration of HD with existing treatment in months	Males	1/μ^hd₀	NA	NA	NA	2.1	1–3 months31 32
	Females	1/μ^hd₁	NA	NA	NA	1.2
HIV biological inputs:
Probability of HIV transmission per sex act	Male to female	β^h₀	0.0068	0.0042	0.008	0.0046	33–35but scaled up
	Female to male	β^h₁	0.0061	0.0014	0.007	0.0031
Behavioural parameters:
Number of clients per FSW per month		n₁	32	50	8	6
Number of FSWs per client per month		n₀	5	6	1.3	∼1	Estimated in fitting
% of sex acts where a condom is used		f	87.5%	79.5%	82%	3% to 34% (reached)
Number of FSWs		N₁	3000	1900	660	750
Number of clients		N₀	Estimated by multiplying number of FSWs by factor n_1/n₀				No data
Baseline epidemiological data:
Prevalence of CT in FSWs			14.5%	5%	26%	>14%^‡
Prevalence of NG in FSWs			15%	22%	15%	>17%^‡
Prevalence of HD in FSWs			0%	0%	No data	∼5%^‡
Prevalence of HIV in FSWs			60%	∼40%	<1%	50% (no data)
Prevalence of HIV in CLs			38% (STI clinic clients)	∼9%	0.25% (no data)	23% (no data)
Data on PPT intervention undertaken:
Year PPT intervention started			2000	2001	2004	1996
Coverage of FSWs reached by PPT intervention			280 (∼10%)	136 (∼7%)	∼80%	407 (54%)
Average duration between PPT treatment visits in months (Note: FSWs will still obtain a single PPT dose if they never return for another visit)		1/ω	2	1	1.5–2	1
Follow-up period in months			12	9	3	9
Prevalence of NG among FSWs at follow-up			∼ 5%	13%	7.9%^*	7%^§
Prevalence of CT amongst FSWs at follow-up			∼5%	7.5%	12.3%^*	3%^§
Prevalence of HD amongst FSWs at follow-up			0%	0%	No data	<1%^§

All model inputs that are assumed to be constant across settings are not shown here but can be seen in supplementary table 1.
↵* Post-intervention STI prevalence data included FSWs that had not received PPT before and so the prevalence data was assumed to be a proxy for all FSWs, not just those reached by the PPT intervention.
↵† The STI durations were varied to fit the models to the observed STI prevalences in different settings and is a measure of the background level of STI treatment.
↵‡ No estimate for baseline prevalence and so the prevalence among women coming for their first visit was used as a lower bound because this is averaged over the whole evaluation.
↵§ No estimate at 9 months and so the prevalence among women coming for their third visit (median number of visits per women) was used as an approximation.
CT, Chlamydia trachomatis; FSW, female sex worker; HD, Haemophilus ducreyi; NG, Neisseria gonorrhoeae; PPT, periodic presumptive treatment; STI, sexually transmitted infection.