Adolescent girls and young women (AGYW) in South Africa remain disproportionately affected by HIV, with prevalence among 15-24-year-olds at 9.4% in 2024 despite expanded access to condoms, HIV testing, and oral PrEP. While oral PrEP is effective, its reliance on daily adherence and regular follow-up has limited impact for many young women. Lenacapavir (LEN), the first long-acting injectable PrEP administered twice yearly, offers a promising alternative that could improve persistence and protection. However, LEN's potential may be undermined by misinformation, particularly around safety and trust, which has been shown in other HIV prevention contexts to reduce uptake and demand. Proactive strategies, such as psychological inoculation, are therefore needed to prebunk misinformation and support future LEN implementation among AGYW. Primary objective: To compare changes in intentions to receive Lenacapavir following misinformation exposure in groups with and without psychological inoculation and behavioural economics boost. Secondary objectives: (1) To compare believability and persuasiveness of misinformation claims and motivational threat associated with misinformation in groups with and without psychological inoculation and behavioural economics boost. (2) To explore subgroup effects by relevant sociodemographic and behavioural factors including HIV risk, PrEP history, COVID-19 vaccine history, general vaccine hesitancy, and information avoidance. The investigators will conduct a two-arm randomized controlled trial of 2-3 inoculation messages that address emerging myths and misinformation about Lenacapavir in South Africa. Participants will be randomly assigned to a control group or an intervention arm: enhanced inoculation message with insights from behavioural economics.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
1,500
Participants enrolled in the control group will receive unrelated information on diabetes topics of the same length as the inoculation messages. Please see Appendix 6 for an example of how this message will be structured. This will make the control group an attention control group and ensure that findings are not confounded by the intervention group spending more time and attentional resources on participation in the study
Participants enrolled in the enhanced inoculation message arm will receive messages that warn them about impending Lenacapavir misinformation and explains why those claims are false or misleading, the messages will be enhanced with insights from behavioural economics see Appendix 5: "Inoculation message with a BE boost" for an example of the inoculation message. As part of the behavioural economics boost, participants may choose to receive a small token (e.g., sticker, badge, bracelet) with a message promoting vaccination as a consistency and commitment prime.
Health Economics and Epidemiology Research Office, University of the Witwatersrand
Johannesburg, South Africa
Lenacapavir intention, at the end of the baseline assessment
Intention to get the Lenacapavir, measured after inoculation intervention and misinformation exposure The intention to get Lenacapavir will be measured on a 0-10 scale.
Time frame: At the end of the baseline assessment
Lenacapavir intention, follow-up
Intention to get Lenacapavir, measured at follow-up survey following misinformation exposure and intervention. Measured on a 0-10 scale
Time frame: 2-4 weeks
Recommend to friends, at the end of the baseline assessment
Intention to recommend Lenacapavir to friends, measured at survey baseline following misinformation exposure and intervention. Measured on a 0-10 scale.
Time frame: At the end of the baseline assessment
Recommend to friends, follow-up
Intention to recommend Lenacapavir to friends, measured at follow-up survey following misinformation exposure and intervention, controlling for baseline pre-intervention/exposure intention. Measured on a 0-10 scale
Time frame: 2-4 weeks
Credibility of inoculated exposure #1
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Credibility of inoculated exposure #2
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Credibility of inoculated exposure #3
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Credibility of inoculated exposure #4
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Credibility of inoculated exposure #5
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Credibility of inoculated exposure #6
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Credibility of inoculated exposure #7,follow-up
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Credibility of inoculated exposure #8,follow-up
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim ,for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Credibility of inoculated exposure #9,follow-up
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Credibility of inoculated exposure #10,follow-up
Extent to which the claim is credible, extent to which the claim makes you anxious or nervous about Lenacapavir, likelihood of your sharing the claim, for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Anxiousness of inoculated exposure #1
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Anxiousness of inoculated exposure #2
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Anxiousness of inoculated exposure #3
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Anxiousness of inoculated exposure #4
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Anxiousness of inoculated exposure #5
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Anxiousness of inoculated exposure #6
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Anxiousness of inoculated exposure #7,follow-up
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Anxiousness of inoculated exposure #8,follow-up
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Anxiousness of inoculated exposure #9,follow-up
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Anxiousness of inoculated exposure #10,follow-up
Extent to which the claim makes you anxious or nervous about lenacapavir for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Shareability of inoculated exposure #1
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Shareability of inoculated exposure #2
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Shareability of inoculated exposure #3
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Shareability of inoculated exposure #4
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Shareability of inoculated exposure #5
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Shareability of inoculated exposure #6
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: At the end of the baseline assessment
Shareability of inoculated exposure #7,follow-up
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Shareability of inoculated exposure #8,follow-up
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Shareability of inoculated exposure #9,follow-up
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
Shareability of inoculated exposure #10,follow-up
Likelihood of your sharing the claim for for the main lenacapavir claims specifically inoculated against and five new claims. All measured on a 1-7 scale
Time frame: 2-4 weeks
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