Manicaland PrEP Uptake Through Interactive Counselling Trial

Overview

Primary Objective: The purpose of this trial is to evaluate the impact of an interactive tablet based counselling session correcting risk perception and addressing ambiguity around availability, usability and effectiveness of PrEP on PrEP uptake within 6 months in adolescent girls and young women (AGYW) aged 18-24 years. Hypothesis: Correcting misperceptions of risks of HIV infection and off-setting ambiguity effects about the availability, usability and efficacy of PrEP, through localized, interactive, tablet-based counselling, will increase uptake of PrEP in HIV-negative AGYW. Study outcomes: The primary outcomes for the study will be risk perception measured in a follow-up survey at 6 months and proportion of women taking up PrEP within 6 months measured with biomarkers of plasma antiretroviral (ARV) drug presence.

With 6 clusters per arm, mean cluster size of 48 individuals, with co-efficient of variation in outcomes between 0.15 to 0.55, the trial will have 80% power to detect difference of 5 - 9 percentage points when baseline PrEP uptake is assumed to be 1%. Primary analysis: A two-stage intention-to-treat (ITT) analysis of cluster level summaries will be used. The parameter of interest is the adjusted risk difference in primary and secondary outcomes. In the first stage, Logistic regression will be used to adjust for confounding variables at the individual level. The model will be fitted using data from both trial arms. The regression model will include terms for the covariates of interest and pair but not trial arm. Adjustment variables will include age group (\<20, 20-24), highest level of education completed, marital status and baseline measures of outcomes. In the second stage, a formal statistical comparison for differences in observed versus expected uptake by arm will be conducted using a two-sided paired significance test with α=0.05. Secondary analysis: In secondary analysis, the complier average causal effect (CACE) will be estimated using an instrumental variables approach. The parameter of interest is the adjusted risk difference in primary and secondary outcomes. Heterogeneity by age and baseline levels of risk and time preferences will also be estimated.