Participants and procedures
We conducted two separate three-arm cluster randomized trials of HIV self-testing delivery models for FSWs in three Zambian transit towns (ClinicalTrials.gov NCT02827240) [25] and urban Uganda (ClinicalTrials.gov NCT02846402) [26]. The two trials followed identical protocols and measured identical outcomes at each time point [27]. The present analysis is a pre-specified secondary analysis from each parent trial.
Trained peer educators each recruited 6 participants in Zambia and 8 in Uganda. In Zambia, participants were recruited in Livingstone, Kapiri Mposhi, and Chirundu, all transit towns. In Uganda, participants were recruited in Kampala, the capital city. In each country, individuals were eligible for participation if they were at least 18 years of age, reported exchanging sex for money or goods at least once in the previous month, self-reported an HIV negative status and no recent (< 3 months) HIV test or an unknown HIV serostatus, and were permanent residence in their town/city of recruitment.
All participants completed four peer educator visits at weeks 0, 2, 6, and 10, and three study visits at baseline prior to randomization and 4 and 16 weeks after the first peer educator visit. We restricted our analysis to participants who self-reported that the results of their most recent HIV test were negative at the 4-week study visit. PrEP-related outcomes were only measured at the 4-week study visit, and thus no 16-week data were included in this analysis.
Randomization
Participants were randomized in groups of one peer educator and 6 participants in Zambia and 8 participants in Uganda. Groups were randomized in a 1:1:1 fashion to one of three randomization arms: 1) direct distribution of the HIV self-test kit from the peer educator to the participant (direct delivery), 2) distribution of a coupon from the peer educator to the participant that could be used to collect the HIV self-test from an existing health facility (coupon delivery), or 3) referral from the peer educator to existing and free of charge standard HIV testing facilities (standard of care). The randomization list was generated in R (Version 3.3.1, The R Foundation for Statistical Computing, Vienna, Austria) in random blocks of size 3, 6, and 9. A separate randomization list was generated for the Zambia and Uganda studies. In both countries, the randomized study assignments were placed in opaque envelopes that were opened by a peer educator and a study staff member once each peer educator group enrolled its target number of participants.
Interventions
All participants completed four peer educator visits, at weeks 0, 2, 6, and 10. At baseline, the peer educator visit was done in a group setting and consisted of HIV prevention counseling, distribution of male condoms, and discussion of where participants could go for HIV testing. In the HIV self-testing arms, participants were additionally given either an HIV self-test kit (direct delivery arm) or coupon that could be used for collection of an HIV self-test at a participating pharmacy or health clinic (coupon delivery). We used the OraQuick Rapid HIV-1/2 Antibody Test (OraSure Technologies, Bethlehem, PA), which has been shown to have a sensitivity of 98.7% and specificity of 99.8% in Zambia under field conditions [28]. Subsequent peer educator visits were one-on-one, and consisted of screening for adverse events, distribution of male condoms, and additional discussion related to HIV testing. Participants in the HIV self-testing arms were also able to ask their peer educator if they needed any help with HIV self-testing. At the fourth peer educator visit (week 10), participants in the HIV self-testing arms received a second HIV self-test or coupon for collection of an HIV self-test at a health clinic.
Measures
Participants completed three surveys using computer-assisted personal interview with a trained research assistant. Interviews occurred at baseline prior to randomization and weeks 4 and 16 following the first peer educator visit.
Demographic characteristics
At baseline, participants were asked their age, literacy (if they could read and write), if they owned a mobile phone, monthly income (Kwacha in Zambia or Ugandan Shillings in Uganda), and if they had a primary partner (e.g., husband or boyfriend who is not a client). Participants were also asked the age at which they began working in sex work. The number of years participants engaged in sex work was calculated as the difference in their current age and the age at which they reported starting working in sex work. Participants were additionally asked to report the number of clients they had on an average working night, and how many of these they used a condom (male or female) with on average. Participants were categorized as inconsistently using condoms (male or female) with clients if the number of clients with whom they used a condom (male or female) on an average night was less than their average number of clients per night. Finally, participants were asked to estimate how likely it was, on a 10-point ladder scale, that they would acquire HIV in the next year.
PrEP acceptability
At the 4-week visit, research assistants read a brief script to participants that introduced daily oral PrEP. The script described daily oral PrEP as a new method for preventing HIV for people who do not have HIV but are at risk of getting it. Participants were told by the research assistant that PrEP has been shown to reduce the risk of HIV infection when taken consistently. Participants were asked how interested they were in taking daily oral PrEP, and their responses were categorized either as “very interested” or less. Injectable PrEP, PrEP in the form of a vaginal microbicide, and a vaginal ring were then introduced to participants as forms of PrEP that were being studied. Injectable PrEP was described as a shot that is given every 3 months. Vaginal microbicides were described as gels or lubricants that were inserted into the participant’s vagina. Vaginal rings were described as rings that are inserted into the vagina that lasts for one month. Participants were asked how interested they were in taking each PrEP modality, interest was again categorized as “very interested” or less.
Acceptability of HIV self-testing during PrEP use
Participants were told by the research assistant that individuals taking PrEP should be tested for HIV every 3 months. Participants were then asked if they would be willing to test for HIV every three months. This question did not specify which type of testing (e.g., self-test or standard facility-based testing). Finally, participants were asked if they would prefer standard HIV testing at a clinic or HIV self-testing for testing while taking PrEP.
Statistical analysis
Descriptive characteristics were calculated with proportions for categorical variables and medians and interquartile ranges (IQR) for continuous variables. We calculated the proportion of participants who responded that they would be “very willing” to use each PrEP modality across all study arms. To determine whether exposure to the HIV self-testing intervention led to increased willingness to test for HIV as part of a PrEP program or preference for HIV self-testing versus standard testing, we used mixed effects logistic regression model with a fixed effect for study arm and a random effect for peer educator group. All analyses were conducted separately for the Uganda and Zambia studies. All P-values were two-sided and analyses were run in Stata 14.1 (StataCorp, College Station, TX).