Couples' preferences for a dual-purpose product to prevent both HIV and pregnancy: results of a discrete choice experiment (DCE) in Uganda and Zimbabwe

BACKGROUND: End-user input at early-stage development of biomedical prevention strategies may optimize their design to ensure high uptake and adherence. Male partners are key influencers in women's product use yet seldom are included in woman-centered prevention research. In MTN-045/CUPID, we interviewed couples to assess their preferences for hypothetical dual-purpose, HIV and pregnancy, prevention (DPP) products.
METHODS: Between January-November 2020 we enrolled 400 couples (self-reported HIV-negative women aged 18-40 and their male partners) in Kampala, Uganda and Chitungwiza, Zimbabwe. Using an experimental design, the DCE asked couples to choose between two hypothetical DPP products in a series of 9 choice questions assessing the following attributes: form (oral tablet, vaginal film/insert, vaginal ring); dosing (precoital, daily, weekly, monthly); menstruation (heavier bleeding, spotting, unchanged); side effects (stomach cramps/nausea: rarely, frequently); return to fertility (immediate, 3-, 6-months); vaginal environment (wetter, drier, unchanged). Random-parameters logit models estimated preference weights and relative importance [RI].
RESULTS: Couples' average relationship duration was 5 years (range 0.25 ' 21 years); females were younger than males (mean: 26 vs. 31). Most couples cohabitated, with Zimbabwean couples more commonly married (88% vs. 20%). DPP product preferences differed significantly by country. Ugandan couples highly valued effect on the vaginal environment, showing a strong preference for increased vaginal wetness (RI=2.5, 95% CI: 1.8, 3.2). Zimbabwean couples' choices were influenced by menstruation and side effects (RIs=1.3, 95% CI: 0.9, 1.6) as well as dosing frequency (RI=1.2, 95% CI: 0.8, 1.6). Couples in both countries strongly preferred monthly over daily dosing. Ugandan couples also showed interest in precoital dosing. While product form was relatively less important, on average, couples preferred an oral tablet over a vaginal ring.
CONCLUSIONS: Preferred characteristics of DPP products varied substantially by country. Effects of the product on the body (e.g., side effects, vaginal environment) were relatively more important than product form or dosing frequency, signaling an openness to new product forms and more frequent dosing if preferred characteristics of other attributes were achieved. Differing tolerances for product side effects should be considered during development, alongside leveraging cultural preferences to increase the attractiveness of a DPP product.