Table 2.
Model parameters for PrEP implementation scenarios
| Parameter | Value | Range | Notes |
|---|---|---|---|
| PrEP programme effectiveness | 75% | 50% to 95% | The variation in programme effectiveness reflects uncertainty in both drug efficacy and adherence/retention. |
| Baseline ART coverage among MSM in 2017/18 | 30% | 7% to 60% | ART coverage among MSM in 2014 was reported at 7% 18 (likely to be underestimated as this only includes ART clients who self‐reported as MSM). ART coverage was approximately 60% among the total population 24. We used a default value of 30% and allowed coverage to vary between the estimates for MSM and for the total population. |
| ART scale‐up relative to baseline | 10 ppts increase | 0 to 20 ppts increase | We set ART coverage among MSM in 2021/22 relative to the value in 2017/18. Our default assumption is for a slight scale‐up relative to baseline; we contrast this with maintenance of baseline levels and a larger increase. Since our baseline ART coverage assumptions range up to 60%, an assumption of a 20 percentage point scale‐up encompasses the accomplishment of the UNAIDS 90‐90‐90 targets. |
| PrEP uptake among high‐risk MSM | 10 ppts lower than ART coverage levels | From 0% up to ART coverage levels | As a baseline, we assume that PrEP uptake will be 10 percentage points lower than ART coverage levels. We consider uptake values ranging from 0% up to ART coverage levels. |
| PrEP uptake among low‐risk MSM | |||
| Scenario: PrEP is provided to all HIV‐negative MSM | 10 ppts lower than ART coverage levels | From 0% up to ART coverage levels | |
| Scenario: PrEP is provided to HIV‐negative high‐risk MSM | 0% | No range | No uptake among low‐risk MSM |
| Percentage reduction in condom use for those receiving PrEP | 10% | 0% to 20% | Moderate reduction in condom use in the moderate scenario, no reduction in the ambitious scenario and 20% reduction in the conservative scenario. |
| PrEP unit cost ppy | US$222.18 | US$180 to US$310 | |
| Annual discounting rate | 3% | 1.5% to 4.5% | |
MSM, men having sex with men; PrEP, pre‐exposure prophylaxis; ART, antiretroviral therapy; ppy, per‐person‐per‐year; ppts, percentage points.