Table 2:
South Africa and Zambia’s proposed PrEP initiation and follow-up timeline with routine data collected from hypothetical client examples showing the proposed metric for PrEP success outcomes
| PrEP client 1* | PrEP client 2† | PrEP client 3‡ | PrEP client 4§ | PrEP client 5¶ | PrEP client 6∥ | PrEP client 7** | |
|---|---|---|---|---|---|---|---|
| PrEP initiation visit | |||||||
| Month 0 | |||||||
| HIV status | Negative | Negative | Negative | Negative | Negative | Negative | Negative |
| At risk of infection†† | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| PrEP dispensed | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| PrEP follow-up visits | |||||||
| Month 1 | |||||||
| Returned‡‡ | 1 | 0 | 1 | 0 | 1 | 1 | 1 |
| HIV status | Negative | Unknown | Negative | Unknown | Negative | Negative | Negative |
| At risk of infection†† | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
| PrEP dispensed‡‡ | 1 | 0 | 1 | 0 | 1 | 1 | 1 |
| Month 3 | |||||||
| Returned‡‡ | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
| HIV status | Negative | Unknown | Negative | Negative | Negative | Negative | Negative |
| At risk of infectiont†† | 1 | 1 | 1 | 1 | 0 | 0 | 0 or 1§§ |
| PrEP dispensed‡‡ | 1 | 0 | 1 | 1 | 0 | 0 | 0 |
| Month 6 | |||||||
| Returned‡‡ | 1 | 1 | 0 | 1 | NA | NA | 1 |
| HIV status | Negative | Positive | Unknown | Negative | NA | NA | Negative |
| At risk of infection†† | 1 | NA | 1 | 1 | NA | NA | 0 or1§§ |
| PrEP dispensed‡‡ | 1 | NA | 0 | 1 | NA | NA | 0 |
| Month 9 | |||||||
| Returned‡‡ | 1 | NA | 0 | 1 | NA | NA | 1 |
| HIV status | Negative | NA | Unknown | Negative | NA | NA | Negative |
| At risk of infection†† | 1 | NA | 1 | 1 | NA | NA | 0 or 0§§ |
| PrEP dispensed‡‡ | 1 | NA | 0 | 1 | NA | NA | 0 |
| Month 12 | |||||||
| Returned‡‡ | 1 | NA | 0 | 1 | 1 | NA | 1 |
| HIV status | Negative | NA | Unknown | Negative | Negative | NA | Negative |
| At risk of infection†† | 1 | NA | 1 | 1 | 1 | NA | 0 or 0§§ |
| PrEP dispensed‡‡ | 1 | NA | 0 | 1 | 1 | NA | 0 |
| Individual metrics | |||||||
| Engaged-in-care score | 1 | 0 | 0 | 1 | 1 | 1 | 1 |
| HIV seroconversion score | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
| Appropriately on PrEP score (South Africa’s assumption of risk) | 1 | 0 | 0 | 1 | 1 | 1 | 1 |
| Appropriately on PrEP score (Zambian risk assessment) | 1 | 0 | 0 | 1 | 1 | 1 | 0 |
| PrEP success score | |||||||
| South Africa | 1 | 0 | 0 | 1 | 1 | 1 | 1 |
| Zambia | 1 | 0 | 0 | 1 | 1 | 1 | 0 |
Success ratios can range from 0 to 1. The success ratio is 0·71 (5 of 7 PrEP clients) for the South African programme and 0·57 (4 of 7 PrEP clients) for the Zambian programme. PrEP=pre-exposure prophylaxis. NA=not applicable (because the patient discontinued PrEP in consultation with a provider, or seroconverted).
Client 1 was at risk and on PrEP for the duration of follow-up and never seroconverted (success).
Client 2 seroconverted at the 6-month visit (unsuccessful).
Client 3 was lost to follow-up after 3 months without indication of risk reduction (unsuccessful).
Client 4 missed the PrEP follow-up visit at month 1, but was otherwise on PrEP for the rest of the follow-up period (success).
Client 5 went through seasons of risk and was on PrEP when at risk (success).
Client 6 stopped PrEP after 3 months in consultation with a health provider and is assumed to no longer be at risk of infection (success).
Client 7 was at risk of infection according to the Zambian risk assessment, but was not prescribed PrEP at months 3 and 6 (unsuccessful). The South African metric assumed the client was not at risk because they were not prescribed PrEP (success). At months 9 and 12 the risk assessment in Zambia established the client was not at risk and they were not prescribed PrEP (success). As with the South African metric, this client continued to be a success because they were not prescribed PrEP and were therefore assumed to be at low risk.
If a client had a visit with a health-care provider (initiation or follow-up) and was prescribed or dispensed PrEP in that visit, the client was considered to be at risk. If a client missed a visit and as a result was not prescribed PrEP, they were assumed to still be at risk.
If a client visited a health-care provider and was not prescribed or dispensed PrEP (stopping PrEP) they were considered no longer at risk of HIV acquisition.
The risk score for client 7 differs for the Zambian and South African programmes because of the way risk of infection is measured with routinely-collected data from each country. Zambia documents risk through formal risk assessments, whereas South Africa relies on healthcare counselling to establish risk and this data is not currently recorded. As such, this metric assumes that if a client is prescribed PrEP the health-care provider believes they are at risk of infection