Table 1.
Summary of CAPRISA 004 trial results - HIV protection after 30 months follow-up(5)
| Main analysis | Effectiveness (95%CI) | Adherence | Crude efficacy§ |
|---|---|---|---|
| Intention to treat | 39% (6, 60) | 72% | 54.2% |
| Per protocol | 41% (7, 63) | ||
| Adjusted | 37% (6,58) | ||
| Sub-analysis | |||
| Rural | 43% (5, 67) | NA | |
| Urban | 26% (−59, 67) | NA | |
| High gel adherence | 54% (4,80) | >80% | <67.5% |
| Medium gel adherence | 38% (−67,77) | 50–80% | 47.5–76.0% |
| Low gel adherence | 28% (−40,64) | <50% | >56% |
| at 12 months follow-up | 50% | NA | |
| at 24 months follow-up | 40% | NA | |
§
The observed effectiveness in trials reflect the combination between the real (unmeasured) efficacy of the microbicide and the adherence to the product. Based on the information available, we can crudely estimate the “true” efficacy as the observed effectiveness divided by the observed adherence - The overall adherence during the trial was 72%, which means that the true efficacy could be around 54%, which is similar to the trial effectiveness estimate among high adherers.